Our Vanishing Wild Life: Its Extermination and Preservation

by William T. Hornaday

The course of the disease is very intense, and thus far it has proven incurable in our wild animals. We have lost about 10 antelopes from it, and one deer, usually, in each case, within ten days or two weeks from the discovery of the first outward sign,—the well known swelling on the jaw. One case that was detected immediately upon arrival was very persistently treated by Dr. Blair, and the animal actually survived for four months, but finally it succumbed. From first to last not a single case was cured.

In 1912, the future of the prong-horned antelope in real captivity seems hopeless. We have decided not to bring any more specimens to our institution, partly because all available candidates seem reasonably certain to be affected with lumpy-jaw, and partly because we are unwilling to run further risks of having other hoofed animals inoculated by them. Today we are anxiously wondering whether the jaw disease of the prong-horn is destined to exterminate the species. Such a catastrophe is much to be feared. This is probably one of the reasons why the antelope is steadily disappearing, despite protection.

In 1906 we discovered the existence of actinomycosis among the black mountain sheep of northern British Columbia. Two specimens out of six were badly affected, the bones of the jaws being greatly enlarged, and perforated by deep pits. The black sheep of the Stickine and Iskoot regions are so seldom seen by white men, save when a sportsman kills his allotment of three specimens, we really do not know anything about the extent to which actinomycosis prevails in those herds, or how deadly are its effects. One thing seems quite certain, from the appearance of the diseased skulls found by the writer in the taxidermic laboratory of Frederick Sauter, in New York. The enormous swelling of the diseased jaw bones clearly indicates a disease that in some cases affects its victim throughout many months. Such a condition as we found in those sheep could not have been reached in a few days after the disease became apparent. Now, in our antelopes, the collapse and death of the victim usually occurred in about 10 days from the time that the first swelling was observed: which means a very virulent disease, and rapid progress at the climax. The jaw of one of our antelopes, which was figured in Dr. Blair's paper in the Eleventh Annual Report of the New York Zoological Society (1906) shows only a very slight lesion, in comparison with those of the mountain sheep.

The conclusion is that among the sheep, this disease does not carry off its victims in any short period like 10 days. The animal must survive for some months after it becomes apparent. At least two parties of American sportsmen have shot rams afflicted with this disease, but I have no reports of any sheep having been found dead from this cause.

This disease is well known among domestic cattle, but so far as we are aware it never before has been found among wild animals. The black sheep herds wherein it was found in British Columbia are absolutely isolated from domestic cattle and all their influences, and therefore it seems quite certain that the disease developed among the sheep spontaneously,—a remarkable episode, to say the least. Whether it will exterminate the black mountain sheep species, and in time spread to the white sheep of the northwest, is of course a matter of conjecture; but there is nothing in the world to prevent a calamity of that kind. The white sheep of Yukon Territory range southward until in the Sheslay Mountains they touch the sphere of influence of the black sheep, where the disease could easily be transmitted. It would be a good thing if there existed between the two species a sheepless zone about 200 miles wide.

I greatly fear that actinomycosis is destined to play an important part in the final extinction that seems to be the impending fate of the beautiful and valuable prong-horned antelope. In view of our hard experiences, extending through ten years (1902-1912), I think this fear is justified. All persons who live in country still inhabited by antelope are urged to watch for this disease. If any antelopes are found dead, see if the lower jaw is badly swollen and discharging pus. If it is, bury the body quickly, burn the ground over, and advise the writer regarding the case.

The Rabbit Plague. —One of the strangest freaks of Nature of which we know as effecting the wholesale destruction of wild animals by disease is the rabbit plague. In the northern wilderness, and particularly central Canada, where rabbits exist in great numbers and supply the wants of a large carnivorous population, this plague is well known, and among trappers and woodsmen is a common topic of conversation. The best treatment of the subject is to be found in Ernest T. Seton's "Life Histories of Northern Animals", Vol. I, p. 640 et seq. From this I quote:

"Invariably the year of greatest numbers [of rabbits] is followed by a year of plague, which sweeps them away, leaving few or no rabbits in the land. The denser the rabbit population, the more drastically is it ravaged by the plague. They are wiped out in a single spring by epidemic diseases usually characterized by swellings of the throat, sores under the armpits and groins, and by diarrhea."

"The year 1885 was for the country around Carberry 'a rabbit year,' the greatest ever known in that country. The number of rabbits was incredible. W.R. Hine killed 75 in two hours, and estimated that he could have killed 500 in a day. The farmers were stricken with fear that the rabbit pest of Australia was to be repeated in Manitoba. But the years 1886-7 changed all that. The rabbits died until their bodies dotted the country in thousands. The plague seemed to kill all the members of the vast host of 1885."

The strangest item of Mr. Seton's story is yet to be told. In 1890 Mr. Seton stocked his park at Cos Cob, Conn., with hares and rabbits from several widely separated localities. In 1903, the plague came and swept them all away. Mr. Seton sent specimens to the Zoological Park for examination by the Park veterinary surgeon, Dr. W. Reid Blair. They were found to be infested by great numbers of a dangerous bloodsucking parasite known as Strongylus strigosus, which produces death by anemia and emaciation. There were hundreds of those parasites in each animal. I assisted in the examination, and was shown by Dr. Blair, under the microscope, that Strongylus puts forth eggs literally by hundreds of thousands!