Darwin�s Dogs

Canine genetics papers often contain a reference to Charles Darwin, usually to On the Origin of Species, where he said that it is �almost certain that our dogs are descended from several wild stocks.�  This conclusion remained possible until put to rest by modern genome research.  (E.g., Ostrander and Wayne, 2005; Larson, Karlsson, Perri, et al., 2012) 

Wolf in London Zoological Gardens (Stonehenge, 1859)

It is a testament to Darwin's authority that, a century and a half after his major work, his views must be acknowledged even when not borne out by research, and time must be taken to explain how he got it wrong.  His opinion that dogs descended from more than one species of wild canid had a great deal of longevity, and though Konrad Lorenz rejected the idea before genome results nailed its coffin shut, at the time he wrote Man Meets Dog in 1949, Lorenz was still in agreement with Darwin that jackals were part of the history of dogs. 

Darwin was an acute observer of animals and wrote extensively about dogs beginning with his time on the Beagle in the 1830s until he put down his pen, in both books and correspondence, and it is perhaps worth the time to review what he said about dogs for much of it remains true and some perhaps has still to be adequately considered.

Origins of the Domesticated Dog

Having already mentioned Darwin�s belief that dogs came from several wild canid stocks, it will be easiest to begin with this issue.  Perhaps his most comprehensive statement concerning dog origins was provided in The Variation of Animals and Plants under Domestication, published in 1868, where Darwin said:

�[I]t is highly probable that the domestic dogs of the world are descended from two well-defined species of wolf (viz. C. lupus and C. latrans), and from two or three other doubtful species (namely, the European, Indian, and North African wolves); from at least one or two South American canine species; from several races or species of jackal; and perhaps from one or more extinct species.�

Hare Indian Dog (Stonehenge)

Thus, Darwin saw dogs as being domesticated multiple times in multiple cultures, a far broader domesticating interface than anyone would argue now. (The notion that domestic dogs came solely from wolves was suggested in a letter from Charles Lyell to Darwin, October 22, 1859, Letter 2508f. The primary argument was the identical gestation period of the two species. Although Darwin believed dogs came from multiple species, he stated in a letter to Lyell that "we believe that all canine species have descended from one parent." Letter 2510; see also Darwin's letter to Caroline Wedgwood, November 1859.)

Darwin believed that domestication could happen comparatively easily when humans entered an area and encountered almost any type of wild canid:

�The main argument in favour of the several breeds of the dog being the descendants of distinct wild stocks, is their resemblance in various countries to distinct species still existing there.  It must, however, be admitted that the comparison between the wild and domesticated animal has been made but in few cases with sufficient exactness.  Before entering on details, it will be well to show that there is no a prioridifficulty in the belief that several canine species have been domesticated.  Members of the dog family inhabit nearly the whole world; and several species agree pretty closely in habits and structure with our several domesticated dogs. Mr. Galton has shown how fond savages are of keeping and taming animals of all kinds.  Social animals are the most easily subjugated by man, and several species of Canidaehunt in packs.  It deserves notice, as bearing on other animals as well as on the dog, that at an extremely ancient period, when man first entered any country, the animals living there would have felt no instinctive or inherited fear of him, and would consequently have been tamed far more easily than at present.  For instance, when the Falkland Islands were first visited by man, the large wolf-like dog (Canis antarcticus) fearlessly came to meet Byron�s sailors, who, mistaking this ignorant curiosity for ferocity, ran into the water to avoid them: even recently a man, by holding a piece of meat in one hand and a knife in the other, could sometimes stick them at night.� 

The Falkland Islands dog, no longer considered a canine, but rather a member of a separate canid genus, was the subject of a prior blog.  In his notes from the HMS Beagle, Darwin referred to the animal as a large wolf-like fox.  He was one of the last naturalists to see them before they became extinct.  Two different dogs of North America, in Darwin�s opinion, came from different wild canids.  He cited an account of the Hare Indian dog which said it was similar to the coyote, while the Esquimaux dog was similar to the great grey wolf.    

Quoting an account that Esquimaux dogs, when pulling a sledge, remain in a compact body but diverge and separate when they come to thin ice so that their weight might be more evenly distributed, Darwin speculates that this "instinct may possible have arisen since the time, long ago, when dogs were first employed by the natives in drawing their sledges," but he also suggests an alternative source for this behavior: "Arctic wolves, the parent-stock of the Esquimaux dog, may have acquired an instinct, impelling them not to attack their prey in a close pack, when on thin ice."  

Darwin dismisses the argument that North American dogs came from Asia:

Exquimaux Dog (Stonehenge)

�[I]t might be argued that when man first migrated into America he brought with him from the Asiatic continent dogs which had not learned to bark; but this view does not seem probable, as the natives along the line of their march from the north reclaimed, as we have seen, at least two N. American species of Canidae.� 

Not only did Darwin believe that wild canines were easily domesticated, but he also believed that this was still happening, and that domesticated dogs were sometimes bred with wild canids for specific reasons:

�It is a more important consideration that several canine species evince � no strong repugnance or inability to breed under confinement; and the incapacity to breed under confinement is one of the commonest bars to domestication.  Lastly, savages set the highest value � on dogs: even half-tamed animals are highly useful to them: the Indians of North America cross their half-wild dogs with wolves, and thus render them even wilder than before, but bolder: the savages of Guiana catch and partially tame and use the whelps of two wild species of Canis, as do the savages of Australia those of the wild Dingo.  Mr. Philip King informs me that he once trained a wild Dingo puppy to drive cattle, and found it very useful.  From these several considerations we see that there is no difficulty in believing that man might have domesticated various canine species in different countries.  It would indeed have been a strange fact if one species alone had been domesticated throughout the world.�

Darwin saw domestication as generally a good thing.  In The Descent of Man, he said:

�Our domestic dogs are descended from wolves and jackals, and though they may not have gained in cunning and may have lost in wariness and suspicion, yet they have progressed in certain moral qualities, such as in affection, trust-worthiness, temper, and probably in general intelligence.� 

Dingo (Stonehenge)

As will be discussed further below, Darwin�s opinions on the development of breeds of dogs were connected to his belief that domestic dogs came from a number of wild ancestors.  Darwin included few drawings of dogs outside of a behavioral context, so most of the plates included here are taken from two authors he referred to, Stonehenge and Youatt.

The HMS Beagle

While on the expedition of the HMS Beagle, Darwin made many notes about dogs.  At an estancia at Berguelo on the Pampas, he wrote down some observations about sheep guarding dogs in the area:

�I saw and heard of the shepherd-dogs of the country.  When riding, it is a common thing to meet a large flock of sheep guarded by one or two dogs, at the distance of some miles from any house or man.  I often wondered how so firm a friendship had been established.  The method of education consists in separating the puppy, while very young, from the bitch, and in accustoming it to its future companions.  A ewe is held three or four times a day for the little thing to suck, and a nest of wool is made for it in the sheep-pen; at no time is it allowed to associate with other dogs, or with the children of the family.  The puppy is, moreover, generally castrated; so that, when grown up, it can scarcely have any feeling in common with the rest of its kind.  From this education it has no wish to leave the flock, and just as another dog will defend its master, man, so will these the sheep.  It is amusing to observe, when approaching a flock, how the dog immediately advances barking, and the sheep all close in his rear, as if round the oldest ram.  These dogs are also easily taught to bring home the flock, at a certain hour in the evening.  Their most troublesome fault, when young, is their desire of playing with the sheep; for in their sport they sometimes gallop their poor subjects most unmercifully.�

An observation published towards the end of Darwin�s life came from his travels around South America aboard the Beagle:

�When the Fuegians are hard pressed by want, they kill their old women for food rather than their dogs; for, as we were assured, �old women no use�dogs catch otters.�� (Letter 203, March 30, 1833, says this information came from what a Fuegian boy told a Sealing Captain.)

The Fuegian dogs were also good at getting "shell-fish":

�In [Tierro del Fuego], so I am informed by Mr. Bridges, the Catechist to the Mission, the dogs turn over the stones on the shore to catch the crustaceans which lie beneath, and they �are clever enough to knock off the shell-fish at a first blow;� for if this be not done, shell-fish are well known to have an almost invincible power of adhesion.�  

The shell-fish may have been limpets.  These dogs were also "excellent swimmers, and ready to bring any bird out of the sea," and made good watchdogs.  (Letter 2643)

Darwin�s Pets

Dog in Humble and Affectionate Frame of Mind (Darwin, Expression of Emotions, 1873)

Darwin makes frequent reference to his own dogs.  In describing a difference in behavior patterns of large and small dogs, he includes observations of a terrier he owned:

�Dogs and jackals take much pleasure in rolling and rubbing their necks and backs on carrion.  The odour seems delightful to them, though dogs at least do not eat carrion.  Mr. Bartlett has observed wolves for me, and has given them carrion, but has never seen them roll on it.  I have heard it remarked, and I believe it to be true, that the larger dogs, which are probably descended from wolves, do not so often roll in carrion as do smaller dogs, which are probably descended from jackals.  When a piece of brown biscuit is offered to a terrier of mine and she is not hungry (and I have heard of similar instances), she first tosses it about and worries it, as if it were a rat or other prey; she then repeatedly rolls on it precisely as if it were a piece of carrion, and at last eats it.  It would appear that an imaginary relish has to be given to the distasteful morsel; and to effect this the dog acts in his habitual manner, as if the biscuit was a live animal or smelt like carrion, though he knows better than we do that this is not the case.  I have seen this same terrier act in the same manner after killing a little bird or mouse.� (See Letter 13782, in which spaniels and a poodle are described as rolling over morsels, such as dried figs.)

In the same book that includes this description, The Expression of the Emotions in Man and Animals (1872), Darwin also mentions a large dog he owned:

�I formerly possessed a large dog, who, like every other dog, was much pleased to go out walking.  He showed his pleasure by trotting gravely before me with high steps, head much raised, moderately erected ears, and tail carried aloft but not stiffly.  Not far from my house a path branches off to the right, leading to the hot-house, which I used often to visit for a few moments, to look at my experimental plants.  This was always a great disappointment to the dog, as he did not know whether I should continue my walk; and the instantaneous and complete change of expression which came over him, as soon as my body swerved in the least towards the path (and I sometimes tried this as an experiment) was laughable.  His book of dejection was known to every member of the family, and was called his hot-house face.  This consisted in the head drooping much, the whole body sinking a little and remaining motionless; the ears and tail falling suddenly down, but the tail was by no means wagged.  With the falling of the ears and his great chaps, the eyes became much changed in appearance, and I fancied that they looked less bright.�

Referring to the terrier, Darwin describes the habitual movement by which she shows her delight, �namely, by licking the air as if it were my hand.�  Noting how common this behavior is, and that dogs will even lick cats with whom they have become friends, he connects the behavior to a possible origin:

�This habit probably originated in the females carefully licking their puppies�the dearest object of their love�for the sake of cleansing them.  They also often give their puppies, after a short absence, a few cursory licks, apparently from affection.�

Dogs in Darwin's Correspondence

Darwin does not name his dogs in his books, but a letter of January 10, 1825, refers to a family pet, Spark. (Sounds like a terrier to me.)  Another mentions Shelah and Spark looking "the pictures of melancholy."  (Letter 17) Spark was lent out when a neighbor needed a watch dog, but Czar had to be given Dr. Parker, "having bit another person," but in the new location "there are a profusion of rats and mice about for her to kill." (Letter 18, December 4, 1825)

When Spark died, after giving birth to one puppy, Marianne Parker wrote to Darwin that she would miss that "poor little black nose." (Letter 23)  Darwin himself reacted emotionally, writing that "I do not know how to express myself clearly."  (Letter 24) A subsequent letter revealed that Spark died because her puppies were too large for her to bear them and none were born alive. (Letter 27)  

Canine Behavior

Dog Approaching Another Dog with Hostile Intention (Darwin, Expression)

As already described, Darwin sought to trace behavior of dogs back to wolves or jackals, but sometimes saw it going only to one of the ancestors:

�Dogs, when they wish to go to sleep on a carpet or other hard surface, generally turn round and round and scratch the ground with their fore-paws in a senseless manner, as if they intended to trample down the grass and scoop out a hollow, as no doubt their wild parents did, when they lived on open grassy plains or in the woods.  Jackals, fennecs, and other allied animals in the Zoological Gardens, treat their straw in this manner; but it is a rather odd circumstance that the keepers, after observing for some months, have never seen the wolves thus behave.  A semi-idiotic dog�and an animal in this condition would be particularly liable to follow a senseless habit�was observed by a friend to turn completely round on a carpet thirteen times before going to sleep.�

Some behaviors went back to both ancestors:

�Dogs after voiding their excrement often make with all four feet a few scratches backwards, even on a bare stone pavement, as if for the purpose of covering up their excrement with earth, in nearly the same manner as do cats.  Wolves and jackals behave in the Zoological Gardens in exactly the same manner, yet, as I am assured by the keepers, neither wolves, jackals, nor foxes, when they have the means of doing so, ever cover up their excrement, any more than do dogs.  All these animals, however, bury superfluous food�. [This is] a purposeless remnant of an habitual movement, which was originally followed by some remote progenitor of the dog-genus for a definite purpose, and which has been retained for a prodigious length of time.�

Aggression and Submission

In the Expression of Emotions, Darwin described a number of contrasting types of behavior, including the considerable difference between preparing to attack and attempting to submit:

Dog Caressing His Master (Darwin, Emotions)

�When a dog approaches a strange dog or man in a savage or hostile frame of mind he walks upright and very stiffly; his head is slightly raised, or not much lowered; the tail is held erect and quite rigid; the hairs bristle, especially along the neck and back; the pricked ears are directed forwards, and the eyes have a fixed stare�. These actions, as will hereafter be explained, follow from the dog�s intention to attack his enemy, and are thus to a large extent intelligible.  As he prepares to spring with a savage growl on his enemy, the canine teeth are uncovered, and the ears are pressed close backwards on the head; but with these latter actions, we are not here concerned.  Let us now suppose that the dog suddenly discovers that the man whom he is approaching, is not a stranger, but his master; and let it be observed how completely and instantaneously his whole bearing is reversed.  Instead of walking upright, the body sinks downwards or even crouches, and is thrown into flexuous movements; his tail, instead of being held stiff and upright, is lowered and wagged from side to side; his hair instantly becomes smooth; his ears are depressed and drawn backwards, but not closely to the head; and his lips hang loosely.  From the drawing back of the ears, the eyelids become elongated, and the eyes no longer appear round and staring.  It should be added that the animal is at such times in an excited condition from joy; and nerve-force will be generated in excess, which naturally leads to action of some kind.�

Here also, he found it expedient to mention his terrier:

�Dogs when approaching a strange dog, may find it useful to show by their movements that they are friendly, and do not wish to fight.  When two young dogs in play are growling and biting each other�s faces and legs, it is obvious that they mutually understand each other�s gestures and manners.  There seems, indeed, some degree of instinctive knowledge in puppies and kittens, that they must not use their sharp little teeth or claws too freely in their play, though this sometimes happens and a squeal is the result; otherwise they would often injure each other�s eyes.  When my terrier bites my hand in play, often snarling at the same time, if he bites too hard and I say gently, gently, he goes on biting, but answers me by a few wags of the tail, which seems to say �Never mind, it is all fun.�  Although dogs do thus express, and may wish to express, to other dogs and to man, that they are in a friendly state of mind, it is incredible that they could ever have deliberately thought of drawing back and depressing their ears, instead of holding them erect,--of lowering and wagging their tails, instead of keeping them stiff and, etc., because they knew that these movements stood in direct opposition to those assumed under an opposite and savage frame of mind.�

Anyone who owns dogs knows that they sometimes have relationships that cannot be explained by relative size or strength.  Darwin was no exception:

�The feeling of affection of a dog towards his master is combined with a strong sense of submission, which is akin to fear.  Hence dogs not only lower their bodies and crouch a little as they approach their masters, but sometimes throw themselves on the ground with their bellies upwards.  This is a movement as completely opposite as is possible to any show of resistance.  I formerly possessed a large dog who was not at all afraid to fight with other dogs; but a wolf-like shepherd-dog in the neighbourhood, though not ferocious and not so powerful as my dog, had a strange influence over him.  When they met on the road, my dog used to run to meet him, with his tail partly tucked in between his legs and hair not erected; and then he would throw himself on the ground, belly upwards.  By this action, he seemed to say more plainly than words, �Behold, I am your slave.'"

That canine submissiveness was understood even in antiquity, see the first plate in Anthropomorphism in Antiquity.  

Barking

Darwin attempted to fathom why dogs bark:

�That the pitch of the voice bears some relation to certain states of feeling is tolerably clear.  A person gently complaining of ill-treatment, or slightly suffering, almost always speaks in a high-pitched voice.  Dogs, when a little impatient, often make a high piping note through their noses, which at once strikes us as plaintive; but how difficult it is to know whether the sound is essentially plaintive, or only appears so in this particular case, from our having learnt by experience what it means!�

He notes that tamed jackals and Canis latrans (coyote) of North America barked, but believed this barking was �a noise not proper to any species of the genus� besides these two.  Here again he sees a difference between some large and some small dogs:

�Under the expectation of any great pleasure, dogs bound and jump about in an extravagant manner, and bark for joy.  The tendency to bark under this state of mind is inherited, or runs in the breed: greyhounds rarely bark, whilst the Spitz-dog barks so incessantly on starting for a walk with his master that he becomes a nuisance.�

In The Descent of Man, Darwin saw barking as having a communicative value with humans: 

�It is a more remarkable fact that the dog, since being domesticated, has learnt to bark in at least four or five distinct tones.  Although barking is a new art, no doubt the wild parent-species of the dog expressed their feelings by cries of various kinds.  With the domesticated dog we have the bark of eagerness, as in the case; that of anger, as well as growling; the yelp or how of despair, as when shut up; the baying at night; the bark of joy, as when starting on a walk with his master; and the very distinct one of demand or supplication, as when wishing for a door or window to be opened.�

Play

Italian Greyhounds (Stonehenge)

Noting that dogs often tuck their tails in play, Darwin wondered if dogs, when chasing foxes, attempt to bite their tails:

�When two young dogs chase each other in play, the one that runs away always keeps his tail tucked inwards.  So it is when a dog, in the highest spirits, careers like a mad creature round and round his master in circles, or in figures of eight.  He then acts as if another dog were chasing him.  This curious kind of play, which must be familiar to every one who has attended to dogs, is particularly apt to be excited, after the animal has been a little startled or frightened, as by his master suddenly jumping out on him in the dusk. In this case, as well as when two young dogs are chasing each other in play, it appears as if the one that runs away was afraid of the other catching him by the tail; but as far as I can find out, dogs very rarely catch each other in this manner. I asked a gentleman, who had kept foxhounds all his life, and he applied to other experienced sportsmen, whether they had ever seen hounds thus seize a fox; but they never had.�

I cannot help but suspect that the passage referring to a master jumping out on a dog at dusk is a description of how Darwin himself sometimes played with his dogs. Celebration is a behavior that Darwin finds across canines:

�Almost all the expressive movements now described, with the exception of the grinning from joy, are innate or instinctive, for they are common to all the individuals, young and old, of all the breeds.  Most of them are likewise common to the aboriginal parents of the dog, namely the wolf and jackal; and some of them to other species of the same group.  Tamed wolves and jackals, when caressed by their masters, jump about for joy, wag their tails, lower their ears, lick their master�s hands, crouch down, and even throw themselves on the ground belly upwards. I have seen a rather fox-like African Jackal, from the Gaboon, depress its ears when caressed.  Wolves and jackals, when frightened, certainly tuck in their tails; and a tamed jackal has been described as careering round his master in circles and figures of eight, like a dog, with his tail between his legs.�   

In a passage from The Descent of Man, Darwin finds that dogs may even have a sense of humor:

Bloodhound (Stonehenge)

�Dogs show what may be fairly called a sense of humour, as distinct from mere play; if a bit of stick or other such object be thrown to one, he will often carry it away for a short distance; and then squatting down with it on the ground close before him, will wait until his master comes quite close to take it away.  The dog will then seize it and rush away in triumph, repeating the same manoeuvre, and evidently enjoying the practical joke.�

Development of Breeds

As already mentioned, Darwin did not believe that the diversity of dogs could be solely explained by breeding choices subsequent to domestication: 

�[W]ho will believe that animals closely resembling the Italian greyhound, the blood hound, the bull-dog, pug-dog, or Blenheim spaniel, etc.�so unlike all wild Canidae�ever existed in a state of nature?  It has often been loosely said that all our races of dogs have been produced by the crossing of a few aboriginal species; but by crossing we can only get forms in some degree intermediate between their parents; and if we account for our several domestic races by this process, we must admit the former existence of the most extreme forms, as the Italian greyhound, bloodhound bull-dog, etc., in the wild state.  Moreover, the possibility of making distinct races by crossing has been greatly exaggerated.�

Darwin believed some variation was due to crossing the aboriginal stocks:

Bulldog (Stonehenge)

�[T]he form of the greyhound may be partly accounted for by descent from some such animal as the slim Abyssinian Canis simensis, with its elongated muzzle; that of the larger dogs from the larger wolves, and the small and slighter dogs from the jackals: and thus perhaps we may account for certain constitutional and climatal differences�. The intercrossing of the several aboriginal wild stocks, and of the subsequently formed races, has probably increased the total number of breeds, and, as we shall presently see, has greatly modified some of them. But we cannot explain by crossing the origin of such extreme forms as thoroughbred greyhounds, bloodhounds, bulldogs, Blenheim spaniels, terriers, pugs, etc., unless we believe that forms equally or more strongly characterised in these different respects once existed in nature.�

Egypt

Darwin saw the plates of Rosellini described in a prior piece:

�I have looked through the magnificent works of Lepsius and Rosellini, and on the Egyptian monuments from the fourth to the twelfth dynasties (i.e. from about 3400 B.C. to 2100 B.C.) several varieties of the dog are represented; most of them are allied to greyhounds; at the later of these periods a dog resembling a hound is figured, with drooping ears, but with a longer back and more pointed head than in our hounds.  There is, also, a turnspit, with short and crooked legs, closely resembling the existing variety; but this kind of monstrosity is so common with various animals � that it would be rash to look at the monumental animal as the parent of all our turnspits�.�

He does not fall into the trap of believing that the resemblance of these dogs to modern breeds means that the modern breeds are actually ancient:

Spanish Pointer (Stonehenge)

�We thus see that, at a period between four and five thousand years ago, various breeds, viz. pariah dogs, greyhounds, common hounds, mastiffs, house-dogs, lapdogs, and turnspits, existed, more or less closely resembling our present breeds.  But there is not sufficient evidence that any of these ancient dogs belonged to the same identical sub-varieties with our present dogs.�

Pointers

Darwin must have gone on some hunts, for he watched hunting dogs at work:

�It may be doubted whether any one would have thought of training a dog to point, had not some one dog naturally shown a tendency in this line; and this is known occasionally to happen, as I once saw, in a pure terrier: the act of pointing is probably, as many have thought, only the exaggerated pause of an animal preparing to spring on its prey.  When the first tendency to point was once displayed, methodical selection and the inherited effects of compulsory training in each successive generation would soon complete the work; and unconscious selection is still in progress, as each man tries to procure, without intending to improve the breed, dogs which stand and hunt best.�

He observes that although the English pointer �certainly came from Spain,� the two do not look much alike any more. 

He also found the behavior of dogs in retrieving worthy of consideration:

English Pointer (Stonehenge)

�Mr. Colquhoun winged two wild-ducks, which fell on the further side of a stream; his retriever tried to bring over both at once, but could not succeed; she then, though never before known to ruffle a feather, deliberately killed one, brought over the other, and returned the dead bird.  Col. Hutchinson relates that two partridges were shot at once, one being killed, the other wounded; the latter ran away, and was caught by the retriever, who on her return came across the dead bird; �she stopped evidently greatly puzzled, and after one or two trials, finding she could not take it up without permitting the escape of the winged bird, she considered a moment, then deliberately murdered it by giving it a severe crunch, and afterwards  brought away both together.  This was the only known instance of her ever having wilfully injured any game.� Here we have reason though not quite perfect, for the retriever might have brought the wounded bird first and then returned for the dead one, as in the case of the two wild-ducks.�

Mutations

Curt Stern, whose human genetics course at Berkeley opened many eyes, including mine, said that we must never forget that Darwin was developing his ideas without the benefit of Mendel�s understanding of genetics. (Gregor Mendel did know about Darwin. Richard Dawkins (2009) describes opening a copy of On the Origin in the library of Mendel's monastery in Brno and finding Mendel's margin notes.) 

As far as I know, Darwin never called the sudden appearance of a trait a mutation.  (He did use �mutations� when referring to all the changes in physical conditions and species in a geographic area.)  Instead, he referred to monstrosities:

Pugs (Stonehenge)

�Some of the peculiarities characteristic of the several breeds of the dog have probably arisen suddenly, and, though strictly inherited, may be called monstrosities; for instance, the shape of the legs and body in the turnspit of Europe and India; the shape of the head and the under-hanging jaw in the bull-dog and pug-dog, so alike in this one respect and so unlike in all others.  A peculiarity suddenly arising, and therefore in one sense deserving to be called a monstrosity, may, however, be increased and fixed by man�s selection.  We can hardly doubt that long-continued training, as with the greyhound in coursing hares, as with water-dogs in swimming�and the want of exercise, in the case of lapdogs�must have produced some direct effect on their structure and instincts.�

Breeding as Imitating Natural Selection

Darwin frequently observed that breeding dogs with the certain desirable traits mimicked natural selection:

�We may confidently infer that no man ever selected his water-dogs by the extent to which the skin was developed between their toes; but what he does, is to preserve and breed from those individuals which hunt best in the water, or best retrieve wounded game, and thus he unconsciously selects dogs with feet slightly better webbed. The effects of use from the frequent stretching apart of the toes will likewise aid in the result.  Man thus closely imitates Natural Selection.�

Dogs have altered their relationship to our livestock in the process of domestication:

Poodle (Youatt)

�It is scarcely possible to doubt that the love of man has become instinctive in the dog.  All wolves, foxes, jackals, and species of the cat genus, when kept tame, are most eager to attack poultry, sheep, and pigs; and this tendency has been found incurable in dogs which have been brought home as puppies from countries such as Tierra del Fuego and Australia, where the savages do not keep these domestic animals.  How rarely, on the other hand, do our civilised dogs, even when quite young, require to be taught not to attack poultry, sheep, and pigs! No doubt they occasionally do make an attack, and are then beaten; and if not cured, they are destroyed; so that habit and some degree of selection have probably concurred in civilising by inheritance our dogs.� 

Conclusion

Darwin worked without genetics, without much of a timeline beyond that man must have existed for �incomparably longer� than 6,000 years, and with little paleontology or archeology, though he did have the images brought back from the early British explorers in Egypt and Mesopotamia.  His sources were often letters he received from others, second- and third-hand information that he had no way of validating but which he often felt he could trust. He saw many types of canids aboard the Beagle, but knew wolves and jackals mostly from London�s Zoological Gardens.  Photography was still in its infancy but naturalists were expected to have artistic skills in that age that most of them could not conceive of now. 

Despite such limitations, he fathomed a changing biological world and applied a principle to it that shocks the world to this day.  Given our modern tendency to look to genetics�more narrowly, genome research�before everything else in describing canine evolution, it is refreshing to read someone drawing wisdom from whatever limited sources are available.

Variations in behavior are particularly important to Darwin, with small dog behavior coming from jackals and large dog behavior from wolves.  Although he was not right about this, Darwin presented issues that still bear discussion.  How is the extreme variability in the dog phenotype to be explained?  What mutations have happened more than once?  How similar were dogs depicted on Egyptian tombs to breeds that look much the same now?  How conscious were men of prior ages that they were refining traits for increased utility of the dogs they employed?  Why is barking more common in dogs than wild canids? Do domestic dogs in specific areas resemble wild canids of those areas, and how much interbreeding occurs? What behaviors carry over from wild canids, and what do not?     

There was a time when I thought I would be a biologist, but that world closed for me long ago.  I do not know if I would have made any contribution worthy of anyone�s attention, but I do know that had I pursued such dreams, I would have worked in the shadow of a great figure.  There is no equivalent in the law, or in most disciplines. In the psychology of the ancient world, Darwin might have been made a deity, like Asklepios to medicine.  His fate, from much of the modern spiritual community, has not been nearly as positive. 

My senior advisor at Berkeley, Richard Dawkins, then an Assistant Professor in the Zoology Department, warned me against making casual references without reading what Darwin really said.  Having put Darwin in a box for forty years, it is wonderful to find that turning the pages is still a pleasure, even more than before.

Bibliography:

1. Clutton-Brock, J. (1977). Man-Made Dogs. Science, 197(4311), 1340-1342) (recounting history of classification of Flakland Islands wolf).
2. Darwin, C. (1971). The Descent of Man, and Selection in Relation to Sex.  John Murray, London.
3. Darwin, C. (1873).  The Expression of the Emotions in Man and Animals.  Appleton & Co., New York.
4. Darwin, C. (1859). On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. John Murray, London.
5. Darwin, C. (1868). The Variation of Animals and Plants under Domestication. John Murray, London.
6. Dawkins, R. (2009).  The Greatest Show on Earth: The Evidence for Evolution.  Free Press, New York.   
7. Derr, M. (2009). Darwin's Dogs: Celebrating the Bicentennial of the Father of Evolution. The Bark (February 27, 2009).
8. Larson, G., Karlsson, E.K., Perri, A., et al. (2012). Rethinking Dog Domestication by Integrating Genetics, Archeology, and Biogeography. Proceedings of the Naitonal Academy of Sciences, 109(23), 8878-83.
9. Lorenz, K. (1954). Man Meets Dog. Methuen, London. (Translation of So kam der Mensch auf den Hund (1949), G. Borotha-Schoeler, Vienna); Lorenz's rejection of the jackal ancestry of domestic dogs is found in his introduction to The Wild Canids: Their Systematics, Behavioral Ecology and Evolution (Fox, M.W., ed.) (1975). Litton Educational Publishing "Although the golden jackal has to be excluded from being a possible ancestor of most domestic breeds, I still maintain that the races which I orignally have called 'lupus dogs,' e.g., chow, husky, Greenland dogs etc., have a wild ancestor different from that of most or all other breeds." Thus, although Lorenz rejected jackal ancestry, he continued to believe that dogs could be distinguished by the wolf populations from which they descended. 
10. Ostrander, E.A., and Wayne, R.K. (2005). The Canine Genome.   Genome Research, 15, 1706-1716. Cold Spring Harbor Laboratoery Press. 
11. Stonehenge (John Henry Walsh) (1859). The Dog in Health and Disease.  Longman, Green, Longman, and Roberts, London. 
12. Townshend, E. (2009).  Darwin's Dogs: How Darwin's Pets Helped Form a World-Changing Theory of Evolution.  Frances Lincoln.
13. Youatt, W. (1857). The Dog. Leavitt and Allen. New York. 

Thanks to Richard Hawkins, Brian Duggan, and Eric Krieger for additional sources and corrections. Thanks to Richard Dawkins for a note about limpets and for posting part of an email about a conflict regarding evolution that my father had concerning one of his books.  

Diner Not Like Cheers after Customer Gets a Service Dog, but Is This Discrimination?

Cheryl Krist suffers from hereditary essential tremor, arthritis, and asthma, and has been disabled since at least 2003, when she began to use walking aids and a wheelchair.  She acquired a service dog in 2008.

Krist had been a customer of the Coopertown Diner in New York City for 20 years, beginning about 1988, where she went nearly every day for breakfast and lunch.  She often remained in the restaurant for over five hours, and it became her primary social community.  She knew other customers, the employees, and its owners, Michael Kolombos and Fotios Batas.  She encountered no discrimination when she came with a cane, crutches, or in a wheelchair. 

She was prescribed a service dog in 2008. Before she received the dog, she informed the restaurant owners that she would be getting it and that she would be bringing it to the restaurant.  Fotios Batas told her that this was okay as long as the dog was licensed and was truly a service dog, but if it were not, it would be excluded so that the restaurant would not be in violation of health codes. (Actually no licensing could be required, but there was never any issue that the dog was in fact a service dog.)

Krist testified that when she began to bring the dog to the restaurant in December 2008, her treatment by restaurant employees and regular customers changed radically.  The employees became �very cool,� with no more interaction than was necessary to serve her.  An employee that regularly had lunch with her stopped doing so.  Pleasantries with other customers ceased.  Another customer who used to sit with her every day stopped doing so, and even refused to speak with her. 

The owners sometimes yelled at her, Krist alleged.  Batas, �from behind the counter on the opposite side of the restaurant, started at the dog and made growling sounds.� When the dog responded with a sound that Krist described as �boof,� she testified that Batas ordered her to leave the restaurant.  On another occasion, when she took the dog out from under the table to show it to another customer, Batas complained that she was playing with the dog.

Kolombos told Krist that she should sit in the front of the store with the dog, and that after she had her breakfast, she should leave.  Krist began going less frequently, tried to sit near the front, but then went back to her favorite booth.  Twice in 2009, once in February and once in the summer, Krist testified that the owners yelled at her for having the dog lie beside her chair or her booth, rather than under the table, because they said that the dog was potentially imperiling customers and waiters. The owners acknowledged in their testimony that they had asked Krist to keep the dog out of the aisle. 

Lawsuit Filed Against Diner 

Finally, in September 2009, Krist stopped going to the Coopertown Diner.  In December 2009 she filed a lawsuit seeking compensatory and punitive damages and injunctive relief, alleging violations of federal, state, and city anti-discrimination laws.  The complaint said that the actions of the owners of the restaurant had driven Krist to tears. 

The trial court found that the restaurant owners and employees had had friction with Krist but, rejecting some of Krist's testimony, concluded that neither of the owners had ever ordered her to leave the restaurant.  Krist had not proven that the owners �did not attempt to reasonably accommodate� her use of her service dog. It also found no proof that the restaurant or its employees treated Krist any differently because she was disabled or that they �made her feel that she was not welcome because she had a disability.� 

The court did accept that Krist�s friends were no longer as friendly after she began bringing the dog, that her circle of friends changed, and also accepted that the owners had yelled at her about the dog, her handling of it, and its conduct. The court said that Krist may have thought of the restaurant as being like the one in Cheers, �but the ADA does not guarantee that kind of atmosphere.�

Although the owners had yelled at Krist a few times, these incidents were isolated, not �outrageous� or �demeaning� and did not constitute a �constructive denial of access.�  The ADA, according to the trial court, does not require that owners of a public restaurant �not complain, not ask the dog�s owner to control the dog�s behavior in a way that is not inconsistent with everyone else�s use of the restaurant.�  There was, in sum, �no evidence of any discriminatory intent� on the part of the restaurant�s owners and employees.

Second Circuit Finds No Requirement of Civility

On appeal, the Second Circuit Court of Appeals said that Krist was contending that Title III of the ADA imposes a requirement of civility. The circuit court rejected this contention. Citing the ADA (42 U.S.C. 12181-2), the court said that discrimination does include �a failure to make reasonable modifications in policies, practices, or procedures, when such modifications are necessary to afford � services to individuals with disabilities, unless � such modifications would fundamentally alter the nature of such � services.�  Regulations issued under the ADA require reasonable accommodations for service animals. 

The circuit court agreed that Krist did not need to prove that discrimination, if present, was intended.  Congress, in passing the ADA, noted its findings in 42 U.S.C. 12101(a)(5), that �individuals with disabilities continually encounter various forms of discrimination,� well beyond �outright intentional exclusion.�  The court referred to Krist�s testimony concerning Batas growling at her dog in a manner perhaps calculated to bait the dog into barking, but noted that the trial court�s finding that �Krist failed to establish by a preponderance of the evidence that she was excluded from Coopertown after she acquired her service dog � or that the service dog was excluded; or that her access to Coopertown, with or without the dog, was restricted.�

The Second Circuit continued to summarize the trial court�s determinations:

�The court's contrary finding that Krist frequented the restaurant with the dog in a manner that was �not significantly different� from her prior custom was supported by its findings that, over a period of some 10 months, Krist went to the restaurant with the dog �dozens and dozens� of times. This finding was supported by the testimony of Batas and Michael Kolombos that Krist had come to the restaurant with her dog some 90�100 times � and by the testimony of Krist herself that during that 10�month period, except in January, March, and April, she went to Coopertown every other day�. The district court's finding that Krist was neither ordered to leave Coopertown nor asked not to return cannot, on this record, be termed clearly erroneous.�

Krist argued that there had been a �constructive exclusion� from the restaurant. To this the Second Circuit responded:

�Nor was the court required to accept Krist's assertion that shouted criticisms of her handling of the dog or its conduct were unjustified or any suggestion that they were designed to drive her from the premises. For example, the last two �yelling� incidents described by Krist occurred in February and September 2009 when Batas and Michael Kolombos, respectively, yelled at her across the restaurant for having put the dog in the aisle, potentially impeding customer traffic and waiter movements. One was an occasion when Krist was sitting at a table under which the dog could not comfortably lie because of the configuration of the base of the table. Krist had sat at the table despite the availability of seven booths (i.e., all but her favorite) at which she could have sat and put the dog under a booth table. The other occasion was one in which she was sitting in her favorite booth but put the dog in the aisle because of a previous incident in which the dog had found and eaten some indigestible food on the floor under the booth's table; Krist offered no evidence that there was still�or again�food under the table. Thus, with respect to two of the four occasions as to which she complained of yelling, Krist's own testimony supported an inference that she had placed the dog in the aisle unnecessarily and that the shouted requests concerned her creation of a safety hazard, because someone passing by could trip on the dog either as it lay there or because it might suddenly move.�

The Second Circuit saw �no basis for overturning the district court�s findings that Krist was neither actually nor constructively excluded.�  

As to the civility code argument, the circuit court cited Camarillo v. Carrols Corp., 518 F.3d 153 (2^nd Cir. 2008), that �legislation such as the ADA cannot regulate individuals� conduct so as to ensure that they will never be rude or insensitive to persons with disabilities.�  The circuit court also cited the Eighth Circuit, which had held in Cannice v. Norwest Bank Iowa N.A., 189 F.3d 723 (8^th Cir. 1999), that insensitivity alone does not amount to harassment and neither the ADA nor the Civil Rights Act impose a �general civility code.� 

The circuit court affirmed the federal district court�s dismissal of the discrimination claims.

Significance of the Case 

This is a difficult case, and slightly different facts, or perhaps even a slightly different perspective by the trial or appellate courts involved, could have resulted in a very different decision.  If an owner of a restaurant regularly began barking at a service dog in hopes of baiting it into responsive barking so he could exclude the customer and the dog, I have little doubt that a discrimination claim could succeed.  If the owner decided that the service dog had to sit near the front of a restaurant because the seating was not as nice there and regular customers would not have to see or interact with the dog, there would be discrimination.  Although both these things may have happened on a few occasions, Krist was apparently permitted to sit where she wanted, and keep the dog where she wanted so long as she did not block an aisle, a reasonable request in granting an accommodation and one that could be made of person with a walker or a wheelchair. 

If it could have been shown that the employee who stopped eating with Krist did so at the direction of the owners, her case would have been stronger.  Similarly, if other customers stopped socializing with her because of rumors spread by the owners, this would be a level of discrimination a court could not ignore.  The service became cool, but how much did it change?  Bringing the check sooner after Krist finished eating is a rather subjective assessment, and the diner had the right to be business-like, even if it was not always so.  If the owners did not believe the dog was really a service dog, they had recourse to verify its status, but they do not seem to have had such doubts. Resenting the law that compels a business to admit a service dog may be petulant, but if an attitude does not really alter the accommodation being given, it is not actionable.  

Discrimination is often subtle, but sometimes too subtle to lead to damages or an injunction. The fact an employee no longer sat with Krist after she got the dog may have been annoying and unkind on his part, but it was a decision he could make without elevating the matter to a violation of the ADA.  Krist�s friends were not obligated to stay friends if they do not like dogs. Leaving a dog in an aisle where it might trip other customers or waiters can be a source of frustration, and yelling in frustration must be tolerated on occasion.  Life is often uncivil, both for those with disabilities and those without disabilities. 

Could It Have Been Different?

A friend of mine in Manhattan has a service dog, a calm but aloof Shiba Inu, that he takes just about everywhere.  The dog sits or lies, always alert, head up, ears cocked forward, with eyes that look inside you more than at you.  He finds that the dog makes friends for him even when he explains that Hiro works best without being treated as a pet.  He rarely senses any discrimination and has been told by one restaurant that he is always welcome to bring the dog, which has become a minor attraction to the other patrons. 

I spend winters in Arizona, where a musician in the Phoenix symphony has a service dog, a yellow Labrador, that comes on stage and lies beside her as she plays the violin.  When I first saw this I paid more attention to the dog than the music, wondering if some note might get the Lab to moan if he fell asleep.  After a while I no longer thought about it, but it took me some time to adjust to the idea that a service dog could belong in this environment.   

It is hard to say how human dynamics affects what happens when a service dog comes into a room.  The hostility of one controlling figure might turn the rest of those present against the person with the dog.  The welcoming attitude of others might reverse any hostility.  Such things can never be fully accounted for.  There is a thin line between what is discriminatory and what is not.  Each situation is different, and the complexities of human nature often make the law�s decisions seem arbitrary.  I cannot say the courts here were wrong, and I might not have reached a different result, even with my biases, had I been sitting on such an uncomfortable bench.   

Krist v. Kolombos Restaurant, 2012 WL 3002598 (2^nd Cir. 2012)

Long-Term Psychological Benefits from Companion, Therapy and Service Dogs Questioned in Recent Scientific Papers

Research on the psychological benefits animals provide to us can be assigned to studies of (1) pets, (2) therapy animals, and (3) service animals.  Most of the studies involve dogs, though the second category in particular has some serious equine studies. 

Studies of pets usually refer to them as companion animals.  In some cases a distinction is being made or implied to suggest that the study is of animals to which the owners have an emotional connection, though I often think �companion� is preferred so that scientific papers can have a multisyllabic adjective in the title. 

Therapy animals�as I say, usually therapy dogs�may involve studies of relatively casual interactions with therapy dogs that visit patient or resident populations, often at institutions such as mental health facilities, nursing homes, hospitals, etc.  More often, however, therapy dogs have been studied when their participation in a treatment regimen involves relatively specific time frames and objectives with a specific patient or patient group, which is often called animal-assisted therapy. 

Service animals�again primarily service dogs�have been studied less than the first two groups for their psychological benefits, partly because many of the more traditional service dog categories (guide dogs, hearing dogs) are not designed to have psychological benefits.  With the rapid growth of dogs trained for patients, particularly military patients with PTSD, and with autism service dogs appealing to many parents of autistic children, this category is growing rapidly and is beginning to be the subject of intense scientific analysis. 

Some recent review articles covering these three categories of dogs sound a note of caution, even concern, in that some have found that dogs are not always beneficial psychologically or even physically, despite the fact they are trained or introduced to patients in contexts where they are supposed to be, and in some studies the dogs have even been found to work against treatment objectives.  The review articles also discuss recent research that has taken on some of the long-standing assumptions about dogs, e.g., that people with pets recover more quickly after heart attacks than people without pets.  Particularly disturbing is that much prior research is now being criticized for faulty design and overly subjective interpretation of results.

The review papers discussed below, however, are not against the use of dogs, and do not insist that there are no psychological benefits to dogs. They do suggest that to provide scientific support for certain arguments that have been made�e.g., that soldiers and veterans with PTSD need dogs to reduce psychiatric symptomatology�more rigorous research needs to be conducted. 

Negative Psychological Effects of Pets Noted in Australian Study

Studying companion animal relationships in Australia is made easy by the fact that 40% of the country�s households include a dog and 26% a cat.  A recent paper by Jasmin Peacock, Anna Chur-Hansen, and Helen Winefield (2012), though not a review paper, included a lengthy analysis of prior research on companion animals and mental health and concluded that much of it was characterized by methodological weakness:

�[F]ew controlled studies have been conducted to provide empirical support for positive physical or mental health outcomes gained from interacting with companion animals. Previous research has been largely descriptive and conducted with specific populations of convenience such as the aged.� 

These authors note that some prior studies indicate that companion animals may actually exacerbate psychological symptoms, cause higher levels of depression, and increase emotional distress and psychoticism (a personality pattern typified by aggressiveness and interpersonal hostility).  Threat of separation from a companion animal may lead to rejection of medical advice and failure to move out of inappropriate housing situations.   Both from prior studies and the part of the paper that includes original research, the authors conclude that �strong attachment bonds to a companion animal might not necessarily be beneficial and, in some circumstances, might potentially lead to poor health outcomes.� 

They also make an observation relevant to the issue of the psychological effect of service animals:

�The level of attachment between service animals (such as guide dogs for the vision impaired) has attracted little attention in the scientific literature. Given the important role service animals play, a better understanding of the working animal-human bond would be instructive.�

�Pet Effect� Called an Uncorroborated Hypothesis

Harold Herzog (2011), a professor at Western Carolina University, argues that �a generalized �pet effect� on human mental and physical health is at present not a fact but an unsubstantiated hypothesis.�  Herzog says that in modern America, �the public has come to accept as fact the idea that pets can also serve as substitutes for physicians and clinical psychologists.�  This can be called �the pet effect,� a term Karen Allen (2003) used to describe the popular idea that living with an animal improves human health, psychological well-being, and longevity. 

Herzog makes a crucial observation that has largely escaped other researchers, which is that there has been a strong media bias.  People like to read stories about how good their pets are for them, but �studies in which pet ownership has been found to have no impact or even negative effects on human physical or mental health rarely make headlines.�  He notes a study (Parker et al., 2010) which looked at 425 heart-attack victims and �found pet owners were more likely than non-pet owners to die or suffer remissions within a year of suffering their heart attack (22% vs. 14%).�  This throws into doubt Friedmann et al. (1980), a study on which I made much in Service and Therapy Dogs in American Society (pp. 8, 95). 

The lack of media attention may also explain part of another phenomenon, which Herzog calls the �file drawer effect.�  This is a tendency of researchers not to publish results that are not positive towards animal ownership:

�At a session at a 2009 conference on human�animal interactions, for example, one researcher reported that separation from their pets had no effect on the psychological adjustment of college students, another found that interacting with animals did not reduce depression in psychiatric nursing home residents, and a third found no differences in the loneliness of adult pet owners and non-owners. So far, none of these studies have appeared in print.�

Herzog cites studies finding that pet owners are just as lonely as non-pet owners as determined by a standardized �loneliness scale,� were no happier than non-pet owners, and might even be more depressed if they were highly attached to a dog.  One longitudinal study of nearly 12,000 American adults (Gillum and Obisesan, 2010) found that cat or dog ownership was unrelated to mortality rates. 

Herzog also discusses methodological problems with human-animal interaction studies, noting that self-reporting approaches may not be valid.  One study of people suffering from chronic fatigue syndrome (Wells, 2009) found that pet owners described numerous psychological and physical benefits to having pets, yet their scores on standardized measures �indicated that they were just as tired, depressed, worried, and stressed as chronic fatigue sufferers who did not get a pet.� 

Pet Therapy with Children Shows Positive Results, but Broad Conclusions Are Premature

A paper by Layla Esposito, James A. Griffin, and Valerie Maholmes (2011), begins with a statement on the need for more research �on the physical and psychological health benefits that can accrue to children through their interactions with pets, both in daily life and in therapeutic settings.�  They note that as far back as a 1987 National Institutes of Health conference, there has been a belief that more needs to be done, and that this is still true today. 

�To delve into the mechanisms of HAI [human-animal interaction] effects on health and determine who benefits from pet interaction and under what circumstances, larger, more focused studies that include crossover designs (in which subjects receive a sequence of different treatments) and look at environmental variables and a variety of pet species are needed. Well-controlled experiments and research that extends beyond studies of short-term physiological responses are also needed to provide more conclusive evidence of effects on health. Studies aiming to more precisely detect physiological changes that occur in people in the presence of pets could be more powerful if researchers would agree to use a common model and then conduct path analyses to show causal connections among the variables. The fact that studies have been done independently without common data elements limits the extent to which contradictions in findings can be explained.�

Need for Better Research Methods to Study Benefits of Service Animals

Melissa Winkle, Terry Crowe, and Ingrid Hendrix (2012) begin their recent paper with the observation that �few rigorous studies� exist regarding the utility of dogs as an �assistive technology option.�  The authors searched the literature for service animal studies using keywords and found 432 papers that might have been relevant.  After eliminating studies that were anecdotal, reviews, primarily qualitative, and dissertations, they were left with only 23, and 11 more were eliminated for focusing on issues the authors were not concerned with, leaving only 12. 

Unfortunately, in the opinion of the authors of this overview study, all 12 papers they looked at closely �had research design quality concerns including small participant sizes, poor description of the interventions, outcome measures with minimal psychometrics and lack of power calculations.�  The authors acknowledge that some of the weaknesses in prior studies are difficult to overcome, saying, for instance, that it �is difficult to conduct a blind investigation of the benefits of service dogs, so it is impossible to rule out the contribution of participant expectations.� 

There was also a lack of uniformity in the training of the dogs, making comparisons across studies essentially impossible.  �Without knowing the length and quality of the specialized training of the service dog, criteria for dog or person placement readiness or the content, length and quality of the training for dog or person, it is impossible to replicate these studies.�

The authors concede that service dogs were perceived by users as allowing them to decrease their reliance on other people. The studies reaching such conclusions, however, did not look at the opinions of caregivers independently of users. 

As for psychological benefits, studies reported �significant increases in self-esteem, internal locus of control, well-being, and positive affect.�  Persons with progressive conditions such as multiple sclerosis and Parkinson�s disease demonstrated significantly higher positive affect scores, with service dogs moderating the effects of depression.  Psychosocial characteristics did not differ significantly between those partnered with service dogs and those without.

The authors conclude that in order for occupational therapists to make recommendations for the use of service dogs, �the evidence to support such decisions must be strengthened.�  They note that this is particularly critical because of the limited availability of dogs:

�Given the extreme shortage of trained dogs and the potential cost of the dog/person partnership training and care, predicting positive outcomes based on person and dog characteristics are vital. Finally, if we are to recommend service dogs (or any kind of assistance dog) as an assistive technology option, we must study the dog-person evaluation and matching process, training and placement procedures and content, and outcomes for both the person and the dog, across assistance dog training organizations.�

Conclusions

The authors of these overviews do not say that there are no long-term psychological benefits to dogs, but they do say that claims of such benefits need more scientific support than they have received so far.  It is to be hoped that future research, such as that being conducted by NEADS, a service dog training organization, to determine the benefits of service dogs for veterans with PTSD, will have the sort of scientific objectivity that will withstand the criticisms of the authors of the papers discussed here. 

These studies will not stay in ivory towers.  Lawyers will scrutinize them for arguments about whether a tenant who wants to keep his assistance animal can really establish that the animal is providing him with psychological benefits such that a landlord must make a reasonable accommodation to a no-pets policy.  People wanting to take their service dogs to work will have to be more careful about the benefits they claim to receive from the dog, because if the matter goes to trial the lawyer for the employer is likely to bring up such studies in cross-examining the service dog user�s psychologist or doctor. 

The research should also be reviewed closely by mental health and medical professionals who are asked to sign letters for patients who want to live with service animals or take such them onto airplanes.  Professionals should be particularly careful about adopting draft language for such letters when the language is reverse engineered from regulations or legal decisions in order to convince an airline or a landlord that a service animal is providing concrete psychological benefits.  A letter that says the patient is getting better by having the service animal is more than an airline or a landlord will need and may not be supportable by the research.  Given that airlines are now being given the ability to contact a professional�s licensing authority regarding a service dog support letter, medical and psychological professionals must be increasingly cognizant of what they sign. 

Sources:

1. Allen, K. (2003).  Are Pets a Healthy Pleasure: The Influence of Pets on Blood Pressure. Current Directions in Psychological Science, 12, 236-9.
2. Esposito, L., McCune, S., Griffin, J.A., and Maholmes, V. (2011). Directions in Human-Animal Interaction Research: Child Development, Health, and Therapeutic Interventions.  Child Development Perspectives, 5(3), 205-211.
3. Friedmann, E., Katcher, A. H., Lynch, J. J., and Thomas, S. A. (1980). Animal Companions and One-Year Survival of Patients after Discharge from a Coronary Care Unit. Public Health Reports, 95(4), 307.
4. Gillum, R.F., and Obisesan, T.O. (2010). Living with Companion Animals, Physical Activity and Mortality in a US National Cohort.  International Journal of Environmental Research and Public Health, 7, 2452-9.
5. Herzog, H. (2011). The Impact of Pets on Human Health and Psychological Well-Being: Fact, Fiction, or Hypothesis?  Current Directions in Psychological Science, 20(4), 236-239.
6. Parker, G., Gayed, A., Owen, C., Hyett, M., Hilton, T., and Heruc, G. (2010). Survival Following an Acute Coronary Syndrome: A Pet Theory Put to the Test. Acta Psychiatrica Scandinavica, 121, 65�70.
7. Peacock, J., Chur-Hansen, A., and Winefield, H. (2012). Mental Health Implications of Human Attachment to Companion Animals. Journal of Clinical Psychology, 68(3), 292-303 (March 2012).
8. Wells, D.L. (2009). Associations between Pet Ownership and Self-Reported Health Status in People Suffering from Chronic Fatigue Syndrome. Journal of Alternative and Complementary Medicine, 15, 407-413.
9. Winkle, M., Crowe, T.K., and Hendrix, I. (2012). Service Dogs and People with Physical Disabilities Partnerships: A Systematic Review.  Occupational Therapy International, 19(1), 54-66.