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Fauna Series No. 4






Population and Mortality







Other Larger Mammals

Small Mammals


Misc. Diet



Fauna of the National Parks — No. 4
Ecology of the Coyote in the Yellowstone
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BUFFALO (Bison bison bison) in the form of carrion furnish a source of food which at times may be highly important to the coyote. In March 1938 a heavy mortality among the buffalo occurred in Pelican Meadows according to a report by Ranger Watson. On March 20 three of the buffalo observed in Pelican Meadows seemed to be within a few hours of death and a number of others showed signs of extreme weakness. Four carcasses, were found, and seven coyotes were seen in the vicinity of one of them. Tracks of a coyote were found at an old calf carcass near Fern Lake cabin. The dead buffalo in Pelican Meadows furnished the coyotes of that region with food for a number of days, and may have been instrumental in carrying through the winter some of these which otherwise might have perished.

On November 4, 1937, in the Horseshoe, remains of a yearling buffalo were found in a treacherous water hole located in a sedge-covered bog. The buffalo had no doubt drowned. Coyotes were feeding on the carcass and a day later a bear had pulled most of it out of the water.

It is unlikely that coyotes kill many buffalo calves. Some kills have been reported in the park but the reports which have come to my notice have lacked proof that coyotes killed the animals.

Figure 44— A buffalo became mired in this "bottomless" water hole, in a quaking sedge bog, and was apparently drowned. Coyotes fed on part of the carcass and later a bear pulled out the remainder.
Horseshoe, November 1938.


Remains of moose (Alces americanus shirasi) were found in one dropping. For several years the moose population in the park has been officially estimated at about 700. Moose are present in such numbers that in some of the favorite summering areas the willows have been heavily browsed. In winter the moose generally move to higher ground, away from the willow tracts and borders of lakes and streams. Scattered over the park, so that they are seldom seen in winter, they subsist largely on Douglas fir, and various shrubs available in the particular areas used.

Since moose can travel quite readily in deep snow if it is soft, and since they are primarily browsers, they are not affected by snow to the same extent as are the elk. There is relatively little overlapping of moose and elk range in winter in Yellowstone National Park at the present time for few moose are found on the north side in winter. It may be true, of course, that more moose would be found in this area if it were not so badly over browsed.

Moose furnish coyote food mainly in the form of carrion. Near a deep water hole on Geode Creek, adjacent to another "bottomless" water hole in which several elk bad been drowned, I found the carcass of an old cow moose on May 16, 1938.

It is possible that occasionally a calf is found by a coyote. On June 19, 1937, one was made available to coyotes through an accident. In the morning some fishermen found a calf moose in water so deep that it had to stand to keep its head above the surface. It was thought that the animal had fallen off a steep bank. The mother remained near her offspring, preventing the fishermen from rescuing it. By afternoon, the calf had drowned.


The five droppings containing domestic cow were gathered near the Game Ranch not far from one of the ranches still within the borders of the park. The source of this food would undoubtedly be carrion. Such has been found to be the case so generally in studies on areas adjacent to Yellowstone National Park that it appears to be a safe conclusion. However, in other parts of the country, young domestic calves have been reported killed by coyotes under certain circumstances.


Remains of bear (Ursus americanus cinnamomum) found in 43 droppings all represented carrion occasionally made available by the shooting of dangerous campground and roadside bears. Most of the droppings were found in the vicinity of areas where dead bears were known to have been left.

black bear
Figure 45— The black bear is primarily a vegetarian but takes anything that comes his way.
Occasionally he stumbles on an elk calf.
Tower Falls, June 10, 1938.


Coyotes (Canis lestes) feed readily on coyote carcasses even when other food is available. Remains were found in 13 droppings.

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Last Modified: Thurs, Dec 20 2001 10:00:00 pm PDT

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