Predator-Prey Relationships

Unlike coyote, fox, and black bear, mountain lion are strict carnivores; they consume meat exclusively.  Throughout their distribution, their primary prey is deer.  Although deer specialists, they are also prey generalists, in that they compliment their deer diet with other ungulates and a variety of small prey.  In some ecosystems, small prey (e.g., rabbits, rodents, skunks, etc...) represent up to 35% of their diet.

The Trans-Pecos hosts a wealth of big game animals including mule deer, elk, white-tailed deer, aoudad, feral hogs, javelina, and bighorn sheep.  To understand what impact mountain lions have on prey populations, we captured mountain lions, attached GPS radiocollars, and monitored their activity.  The GPS collars allow us to monitor the mountain lions daily via satellites that download 6 locations to our email account. 

Locations are then imported into mapping software so that we can evaluate if mountain lions might be at a kill site.  Clusters of locations in the same area (<200 yards) are a good indicator that a mountain lion has made a kill.  Once cluster sites are identified and the mountain lion leaves the vicinity, we seek landowner access to investigate the kill sites.

In the past year, we have identified 172 possible kill sites and have been permitted to investigate 138 of the clusters.  Of the 138 we have discovered 104 verified kill sites by mountain lions (see pie chart above).

In addition to the kill sites, we also documented 5 scavenged sites that were used by radiocollared mountain lions.  During our first year of study, mountain lions scavenged 3 feral hogs and 2 elk that had died from other causes.   

lion kill

Using GPS and satellite technology, we have investigated 138 potential kill sites of mountain lions, revealing 104 kill sites and 5 scavenged sites. This mountain lion has returned to a feral hog it killed 3 days earlier.

kill chart

The diet of mountain lions as determined by 104 verified kill sites of radiocollared mountain lions in the Davis Mountains. The “other” category is represented by 4 coyotes, 4 skunks, 2 fox, 1 porcupine, and 1 coati.