Part 1

DISEASE IN CAPTIVE WILD MAMMALS AND BIRDS INCIDENCE, DESCRIPTION, COMPARISON

BY HERBERT FOX, M.D.

PATHOLOGIST TO THE ZOOLOGICAL SOCIETY OF PHILADELPHIA, DIRECTOR OF THE WILLIAM PEPPER CLINICAL LABORATORY, UNIVERSITY OF PENNSYLVANIA

WITH A FOREWORD BY CHARLES B. PENROSE, M.D.

PRESIDENT OF THE ZOOLOGICAL SOCIETY OF PHILADELPHIA

PHILADELPHIA, LONDON & CHICAGO J. B. LIPPINCOTT COMPANY

COPYRIGHT, 1923, BY HERBERT FOX

THIS BOOK IS DEDICATED TO CHARLES BINGHAM PENROSE, M.D., PH.D., LL.D. IN GRATEFUL APPRECIATION OF HIS FRIENDSHIP AND OF HIS GUIDANCE AND ENCOURAGEMENT IN ALL MATTERS PERTAINING TO THIS LABORATORY.

CONTENTS

PAGE

FOREWORD—DR. CHARLES B. PENROSE 1

SECTION

I. INTRODUCTION 17

Zoological Classification

Numerical List of Autopsies Upon Which the Work is Based.

II. DISEASES OF THE HEART 48

III. DISEASES OF THE BLOOD VESSELS 66

IV. DISEASES OF THE BLOOD AND BONE MARROW 83

V. DISEASES OF THE LYMPHATIC TISSUES INCLUDING SPLEEN 114

VI. DISEASES OF THE RESPIRATORY TRACT 134

VII. DISEASES OF THE ALIMENTARY TRACT

The Tube Proper 166

The Liver 222

The Pancreas 244

The Peritoneum 260

VIII. DISEASES OF THE URINARY TRACT 263

The Kidney

IX. DISEASES OF THE FEMALE REPRODUCTIVE ORGANS 287

X. DISEASES OF THE MALE REPRODUCTIVE ORGANS 313

XI. DISEASES OF THE DUCTLESS GLANDS.

The Thyroid 316

The Thymus 336

The Suprarenal 336

XII. DISEASES OF THE SKELETON AND ITS JOINTS 343

XIII. DISEASES OF THE CENTRAL NERVOUS SYSTEM AND SPECIAL SENSES 372

The Eye 402

XIV. CONSTITUTIONAL DISEASES 410

XV. THE RELATION OF DIET TO DISEASE BY E. P. CORSON-WHITE, M.D. 415

XVI. NEOPLASMS 462

XVII. THE INFECTIOUS DISEASES.

Tuberculosis 483

Mycosis 558

Streptothricosis 567

Miscellaneous Infections 596

XVIII. ANIMAL PARASITES, THEIR INCIDENCE AND SIGNIFICANCE, BY F. D. WEIDMAN, M.D. 614

LIST OF TABLES

PAGE

1. The incidence of degenerative and inflammatory changes in the heart 51

2. The incidence of hypertrophy and dilatation of the heart with principal associated lesions 57

3. A condensation of the important features of Tables 1 and 2 63

4. The heart-to-body-weight ratios 63

5. The incidence of arteriosclerosis 71

6. The differential percentage of the circulating leucocytes in a number of different animals 84

7. The various types of splenitis 126

8. The incidence of the various types of bronchitis and of pulmonary parasites 142

9. The incidence of the various forms of pneumonia 150

10. An analysis of cases of abscess and gangrene of the lung 156

11. The incidence of gastroenterocolitis, its distribution and an analysis of the causes 182

12. An analysis of the inflammations of the alimentary tract in Ungulata 196

13. An analysis of the inflammations of the alimentary tract in Marsupialia 200

14. An analysis of the cases of pancreatitis, the associated pathology and the details of the anatomy of various orders 252

15. The weight of the thyroid body in relation to body weight 318

16. The incidence of the various enlargements of the thyroid body 326

17. The incidence of cases of degenerative bone disease in the various orders 357

18. The weight of the brain and the relation of this to the body weights in 196 animals 388

19. An analysis of pathological conditions in terms of diet 423

20. An analysis of the diets used in the Philadelphia Garden 426

21. The incidence of tumors 464

22. An analysis of the breeding, captivity and visceral distribution of neoplasms, of tumor-bearing animals 466

23. An analysis of the incidence, character and distribution of tuberculosis 486

24. The incidence of parasites in the zoological orders 630

25. The incidence of heterakis in pheasants 635

26. The incidence of various parasitic orders and families 636

27. The visceral distribution of parasites 639

28. The occurrence of blood parasites in zoological classes 651

FOREWORD

BY

CHARLES B. PENROSE

The work on which this book is based was begun in November, 1901. From that date, systematic autopsies were made on animals dying in the Philadelphia Zoological Garden. Previously autopsies had been made very rarely and only on animals of especial importance and interest. Pathological conditions were occasionally noted in animals subjected to anatomical study. The work was strictly volunteer, for there was no one on whom the Society had the right to call. Dr. Henry C. Chapman, a former Director, whose interest was in physiology and comparative anatomy, made nearly all the autopsies that were made before the beginning of the present work. In the annual reports from the foundation of the Garden in 1872, very few such examinations are recorded. In some reports there are lists of important deaths, but no record of the cause of death.

This state of things was not peculiar to the Philadelphia Garden. It existed in every zoological garden in the world. It exists in most of them to-day. When an animal died it had no interest or value except for its hide and bones. Rare specimens were sent to the Academy of Natural Sciences from the Philadelphia Garden. The great majority, however, were immediately destroyed, and thus during the twenty-nine years from the foundation of the Garden, preceding this work, there have been lost many opportunities—some of which will never recur—of increasing our knowledge of pathology.

This book gives results of the study of animals that have not been subjected to experimental procedures and conditions, and though their mode of life has not been that strictly natural to them, yet they have not been influenced by any of the artificial procedures of the laboratory which are usually followed in investigations on animals. Though the object of the work was the pursuit of knowledge for its own sake, yet results of practical value have followed: hygiene has been improved; disinfection has been made scientific; epidemics have been arrested; some diseases, notably tuberculosis in monkeys, and spiropteriasis in parrots, have been practically eliminated.

The value of the work is recognized by the keepers. Their interest has increased and their morale has improved. The frequent deaths in a large collection of animals are discouraging, and a good animal man must have courage and optimism—traits that are stimulated by the knowledge that every animal that dies is studied to determine the cause of death, and to prevent its recurrence.

Some results of this study are to be considered as “raw material,” while others permit cautious or tentative conclusions. The first include— visceral weights, incidence of certain lesions like anemia and hepatic cirrhoses, occurrence of calculi and observations on weak hind quarters, convulsions and constitutional diseases. The second include—eradication of tuberculosis and spiropteriasis, the response of the mammalian and avian heart to strain and disease viruses, the origin of pneumonia in birds, the genesis of bronchiectasis, the nature of osseous degeneration with relation to diet and alimentary tract, the comparative anatomy, physiology and pathology of the female genitalia, the occurrence of lesions in the thyroid comparable to those in man, the character of kangaroo disease.

Great praise is due Dr. Herbert Fox and his assistants Drs. F. D. Weidman and E. P. Corson-White, for the splendid scientific spirit and thoroughness with which they have done this work, with no adequate remuneration, except the intangible reward appreciated only by the real research worker.

It is a mistake to think that all animals in the wild state are healthy. The healthy wild animals that we see are the survivors, the sick and the weaklings having died. Undoubtedly diseases are fewer than in captive animals; but on the other hand wild animals are exposed to dangers to which captive animals are not exposed—such as lack of care in sickness and old age, starvation, and attacks of enemies that feed on them. The maximum longevities in some species are probably in captive animals. It is doubtful if a wild animal ever reaches the greatest age possible to it.

Many kinds of parasites have been found in wild animals captured only a short time before arriving at the Garden, so that they must have existed in the wild. Thirteen wild cats received from South Carolina within a few days after capture were infested with intestinal, muscular, and pulmonary parasites. Several years ago there were received from the Island of Chincoteague, off the coast of Virginia, a number of native birds recently captured, all of which had mould disease of the air sacs. This happened on several occasions, so that it became necessary to reject all birds from this locality. Among the birds were meadow larks and cardinals.

Hunters not infrequently kill animals with disease, and if more hunters knew enough to recognize the disease there would be more recorded cases. Sick animals are not as likely to be killed by the hunter as healthy ones, as sick animals seek seclusion and do not move about. In many localities of the United States white-tailed deer are infested with the liver-fluke. Trout and other fish in remote mountain streams are found with tapeworms. Round worms and other parasites infest the white rhinoceros in the African forest.

In many instances the parasites and the host, when in health, get on very well together; but when the host weakens the parasites may give him the finishing stroke.

Though some morbid conditions described in this book are peculiar to captivity, yet it seems reasonable to assume that many of the diseases found in captive animals occur also in the wild. Some of the extinct races of animals may have been wiped out by disease.

Captivity causes numerous physical and mental disarrangements. Unaccustomed, unnatural and unvaried food, change of climate and environment, physical and mental degeneration from disuse of muscle and brain, fear, ennui, nostalgia, lack of the exhilaration of chasing and being chased, unsatisfied sexual feeling—all react harmfully on the captive.

No captive animals get their natural food; and though some, like the carnivora, may get approximately their natural food, yet they do not get it in the natural way. They have but little variety and may miss elements important to their well-being. They get only certain cuts— muscle and bone; they do not get blood, guts and glands. The lion’s meat is handed to him. He does not tear down his prey; and one result is that the jaws of the captive-bred lion differ decidedly in shape from the jaws of the wild-bred lion. He gets his food regularly, with awful monotony—twelve pounds of meat at 3.30 p.m. day after day; there is no alternation of feasts and fasts, with consequent change in the balance of the body reserves.

Some animals, such as caribou, the moose, the black cock, the hoatzin, the koala, do not long survive captivity, because it is impracticable to obtain their natural food. Gastrointestinal disease is the commonest disease of wild animals. Twenty-five per cent. of sick humans in civilized communities also suffer from it. On the other hand, many animals become accustomed to the new diet and thrive on it.

Animals also often thrive in a climate very different from that of their natural habitat. Some animals from warm countries, though kept outside without any artificial heat, get on very well during the severe weather of Philadelphia winters, when the temperature often drops to zero Fahrenheit. For the past two years it has been the custom to put outdoors all monkeys—of value—that are suspected of having tuberculosis. The cheap monkeys are killed. The outdoor monkeys are kept in fair sized cages—five feet square and six feet high—usually singly, though sometimes two are together. The vervet, the grivet, the leonine macaque, the yellow baboon, the Hainan gibbon and many others, have not only survived the climatic conditions but have not succumbed to tuberculosis. South American monkeys do not stand cold as well as Old World monkeys, and cannot be kept out in severe winter weather.

The monkeys that are kept indoors during winter have free access to the outside through swinging doors and they often go out voluntarily in the coldest weather. The same is true of other animals. A note made several years ago (February 12, 1914) states: “Temperature last night was 1° F. At 2 P.M. outside temperature 13° F., in carnivora house 25° F., elephant house 38° F., giraffe house 39° F., monkey house 42° F. Two Bengal tigers were voluntarily outside. Monkeys that have been out all winter are: two Barbary apes, Hainan gibbon, lion-tailed macaque, yellow baboon, grivet monkey, pigtailed macaque, and eleven rhesus macaques. All the animals appeared comfortable.”

The physical condition of the animal and the kind of cold—damp or dry— have much to do with its ability to stand low temperatures. Monkeys have passed through very severe winters without damage, and subsequently in a less severe winter have had frozen fingers, toes or tail.

The size of the cage or pen has not as much effect upon the well-being of the animal as might be expected. Reptiles, birds and mammals do as well in cages and pens of medium size as in very large ones. A deer or antelope in a large enclosure does not use all its domain. It usually has a favorite corner near the food, water and shelter, and stays there. Nor has a large enclosure been found perceptibly to diminish mortality from cage-mates. The stronger will follow the weaker until he gets him, no matter what the enclosure. Even in the large flying cage for birds it is necessary to keep out those of a scrappy disposition. From the point of view of the public small enclosures are more satisfactory.

Mental disease in captive animals offers a fascinating field for study— now chiefly speculative. Many conditions are present to produce it—all the conditions that cause prison psychoses in man. And many if not all the insane and perverted acts of animals have their counterpart in the human. Masturbation is very common in mammals. Eating of their own feces, coprophagy, is not infrequent, and is especially notable in one of the highest types—the Chimpanzee. Perhaps occasionally coprophagy may be due to some defect in diet. There is no instinctive disgust at excrement in the lower animals any more than there is in the uneducated child. Nevertheless, eating feces cannot be healthful, and probably does not occur in nature; and occurs only in the human with mental disease.

Some of the insane acts of animals if prevalent in the wild would probably cause the extinction of the race. Such are killing of the young by the father and by the mother; killing of the female by the male, usually during rutting time, in some instances reminding one of Sadism in man. This kind of sexual killing does not often occur in the wild. The female has a better chance to escape, and the male probably does not feel so inclined to damage her when he chooses her himself as when she is chosen for him by his gaoler. When the mother devours her young it is usually shortly after birth. I have, however, the record of a Jungle cat (_Felis chaus_) who ate two of her kittens when they were seven weeks old. Some of the domestic animals devour their young; the sow often does it, and occasionally the bitch.

Sucking, gnawing and eating parts of itself or of a cage-mate is not uncommon in a variety of animals. Bears lick their paws until they are sore; a monkey may gradually gnaw away its tail from the tip to the body; an ocelot (_Felis chibigonazon_) bit open his scrotum and devoured his testicle; a Tasmanian devil (_Sarcophilus ursinus_) bit off one of his front feet at the wrist; a monkey may gradually gnaw away its fingers; and numerous other self-inflicted mutilations occur. Often there is a local irritating cause, as skin disease, lice, or freezing. But in many cases no local cause can be found, as no local cause can be found for thumb-sucking or nail-biting in the human.

The surgery done by monkeys on their frozen fingers and toes is interesting. After the flesh has sloughed the monkey bites off the protruding phalanges, apparently without pain, so that satisfactory well-covered stumps are made.

Animals often mutilate their cage-mates in an amicable way as distinguished from fighting. A bear may lick its mate’s ears until the hair and skin are gone. A monkey may eat its mate’s tail or patches of its skin, the victim lying placidly while the process goes on. Many animals are addicted to perverted acts on their own or their mate’s sexual organs.

It is probable that the phenomena just mentioned are due to confinement, idleness and ennui, and that they do not often happen in nature where an animal is kept busy seeking his food, fighting and avoiding his enemies, attending to his mate or mates, and meeting the various vicissitudes of his environment.

It should be remembered, however, that the members of a wild species vary in intelligence and temperament, as humans do. There are morons and perverts among animals in the wild; but not being coddled by the normal members of the species, they have a poorer chance than has the subnormal human of surviving and of transmitting their peculiarities.

Fear, ennui, loneliness and nostalgia, by affecting the minds of captive animals, react on their physical condition. Some animals have the fear of man bred in them. The young often show it from time of birth. This is especially common in animals that have survived for generations in proximity to man. It is one reason for their survival. The mother and father may have become tame and gentle in captivity and yet the young one may be a wild thing from birth. Such fear is sometimes uncontrollable, an apparently slight cause making the animal dash itself against the fence of the enclosure. It is not mere speculation to discuss the physical effects of the emotions on the animal body. It has been shown that fear, anger, and grief bring about distinct measurable physical changes. Dr. Corson-White has found that the red corpuscles are increased by over two million per cubic centimetre in the blood of a cat frightened by a dog barking at it. The amount of blood sugar is also increased.

Such observations are suggestive in a consideration of the changes that may occur in a captive animal subjected to acute and chronic fear.

The monotony of a captive animal’s life is broken only by feeding, the sight and sounds of others in the same building or nearby, and by visitors. Many animals show their appreciation and pleasure when visitors approach, and some of the more intelligent animals, bears and monkeys and some birds, “show off” apparently to keep the visitors there. When there is nothing doing, some stand swaying their heads, like a weaving horse, or pacing the cage, inanely tagging at each turn the side of the cage with the head or other part of the body—often so persistently that a sore is produced. Nearly all animals are social and suffer from loneliness when kept by themselves. This is true even of the lowly forms. The keeper of the reptile house reported that a giant tortoise became despondent and refused to eat when his companion, a leopard tortoise, was taken from him, and that he braced up as soon as the leopard tortoise was returned. It is not necessary that the companion be of the same species, or even of the same family. A lion or a tiger may be satisfied with a little dog for a companion, and there was an African rhinoceros at the Philadelphia Garden that was very discontented and unhappy when alone and became perfectly satisfied when she was given a domestic goat as a cage-mate; and the huge rhinoceros stood for a good deal of butting and bullying from the goat without retaliating. A sympathetic keeper may do much to relieve the loneliness of the animals in his care.

Nostalgia, or homesickness, has been felt by all men. Some have died of it. The tradition among writers is that it affects young people and those who have been living nearest to a state of nature. In this country the American Indian and the negro are affected more than the whites. Much was written of it after the Franco-Prussian War and the American Civil War. It is a real condition, capable in extreme cases of causing death and of so weakening the sufferer as to make him more susceptible to the invasion of other diseases. At the present day we hear less of it among civilized people than formerly, perhaps because the conception of home has been broadened by modern methods of intercommunication. The wild animal’s conception of home is narrow; he comes directly from it into an environment where he may see many other animals, but not one of his own kind. Predisposing causes of nostalgia are stronger with him than with the human. That home means a great deal to animals is shown by the migration of birds—the return of the carrier pigeon, and of the lost dog, and of the swallow, which returns every year to the same nesting place.

All animals long for the things of nature—open air, earth, grass and water. They are thrilled when their feet touch the sod. Even the hippopotamus gambols when he leaves his concrete house and his feet touch earth and grass.

The face and carriage of many animals cannot express feelings as in the human, though it is not unreasonable to assume that animals may indicate feelings by expression understood by their mates, though not understood or even noticed by man. When they can express it in a human way their feelings may be read. The dejection of nostalgia is especially shown by anthropoid apes. Gorillas have been noted for it from the earliest writers. The orang is prone to it, shows it by his attitude and expression, and sometimes dies of it.