Cougar Predation

[Balam]

(10-13-2020, 01:41 AM)Balam Wrote: Excerpt from A Cougar Hunt on the Rim of the Grand Canyon by Theodore Roosevelt, highlighting the cougar's affinity for horse meat and their success in killing even large breeds such as saddle horses:

"Among domestic animals, while they at times kill all, including, occasionally, horned cattle, they are especially destructive to horses. Among the first bands of horses brought to this plateau there were some of which the cougars killed every foal. The big males attacked full-grown horses. Uncle Jim had killed one big male which had killed a large draft-horse, and another which had killed two saddle-horses and a pack-mule, although the mule had a bell on its neck, which it was mistakenly supposed would keep the cougar away. We saw the skeleton of one of the saddle-horses. It was killed when snow was on the ground, and when Uncle Jim first saw the carcass the marks of the struggle were plain. The cougar sprang on its neck, holding the face with the claws of one paw, while his fangs tore at the back of the neck, just at the base of the skull; the other fore paw was on the other side of the neck, and the hind claws tore the withers and one shoulder and flank. The horse struggled thirty yards or so before he fell, and never rose again. The draft-horse was seized in similar fashion. It went but twenty yards before falling; then in the snow could be seen the marks where it had struggled madly on its side, plunging in a circle, and the marks of the hind feet of the cougar in an outside circle, while the fangs and fore talons of the great cat never ceased tearing the prey. In this case the fore claws so ripped and tore the neck and throat that it was doubtful whether they, and not the teeth, had not given the fatal wounds."

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My belief is that cougars are prone towards equids as they inhabited the same habitats for thousands of years in North and South America, where horses evolved, up until the early Holocene. It's natural that for thousands of years horses were part of the diet of prehistoric cougars in a similar fashion that elk today are. With the return of horses to the Americas, the natural instinct of cougars towards favoring them as prey items could've been activated. 

Despite popular belief, cougars are excellent regulators of feral horse populations, as previous studies posted here before have proven in places such as Argentina and Chile, as cougars dramatically reduce the numbers of foals by focusing predation on them, which as a result reduces the number of potential breeding adults. Bigger males can bring down an adult individual here and there, increasing the predation rates.

From Cougar Predation Rates and Prey Composition in the Pryor Mountains of Wyoming and Montana: 

"Previous studies have found cougar predation upon feral horses (Equus caballus) varies widely. Turner and Morrison (2001) found cougars limited feral horse populations in the White Mountains of California and Nevada, while in other studies cougar predation has been negligible, or attributable to a specialist individual (Knopff and Boyce 2007)."

For transparency purposes, it's important to highlight that they could not identify cougar predation on mustangs in this particular study, nonetheless, predation on this population has been documented in other places. From the American Wild Horse Campaign:

"Studies have shown that a mature mountain lion can kill and feed off one foal every two weeks. In fact, during a 2004 study on the Pryor Mountain area in Montana, only 1 out of 28 foals survived that year, mostly due to mountain lion predation. After coming across killed juvenile mustangs, or living juveniles with large scrap marks on Nevada’s Virginia Range, Biologist Dr. Meeghan Gray set out to study the cause and began researching mountain lions. After capturing and collaring one of the largest female mountain lions on record, she found that 77% of a mountain lion’s diet consisted of young horses. During the 10-month tracking period, the mountain lion was shown to have killed 20 juvenile horses.


In the Montgomery Pass Wild Horse Territory, mountain lion hunting has not happened in decades and as such, the wild horse population is considered to be at an ecologically effective level.

In a recent study, the University of Nevada, Reno researchers state that mountain lions are a top predator in Nevada for ungulates, including wild horses. It also found that wild horses are an important food source for cougars on par with mule deer."

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A 5-year-old stallion is scarred by what appears to have been a lion attack in this photo taken in June. The photo was probably taken the day of the attack; some of the wounds were still bleeding. BLM photo

Continuation on feral horse predation, from the study Ongoing Cougar Research in Alberta, Canada, by Kyle Knopff, Aliah Knopff, and Michelle Bacon:

"At the Central East Slopes Cougar Study site we have collared and monitored 44 different cougars between December 2005 and fall 2008. Most of these animals were outfitted with Global Positioning System (GPS) collars. A fundamental component of this study was to better understand the interactions between cougars and their prey in multiprey systems. To this end, we selected a study area representing a true multi-prey system and containing 8 types of potential wild ungulate prey (white-tailed deer, mule deer, elk, moose, feral horses, mountain goats, bighorn sheep, and caribou).

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Preliminary results demonstrate that while the cougar population as a whole subsists primarily on deer, diets are remarkably diverse and individual preference for prey types appears to play an important role in this diversity. Some individuals, for instance, consume primarily deer, others bighorn sheep, and still others focus on feral horses (which are common in west central Alberta). Distinct differences between the predatory behavior of males and females have also been noted and males tend to kill more large prey (elk, moose, and feral horses) than do females. 

*This image is copyright of its original author

Yet another exciting avenue of research that we have been able to pursue at our west-central Alberta site is to examine the interactions among sympatric large carnivores (specifically cougars and wolves). This is made possible thanks to a simultaneous largescale study of wolves that Nate Webb and Dr. Evelyn Merrill have been conducting in the same study area. Most studies of wolf/cougar interactions that have taken place to date occurred where wolves are re-colonizing (e.g. Yellowstone)."

Adult horses:

*This image is copyright of its original author

*This image is copyright of its original author

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