When people imagine puma dens they might imagine a rocky cave in a wild and inaccessible area. They may also expect dens to be located in the center of a puma’s territory, with the puma returning to this permanent lair each night after hunting. However, these assumptions are based much more on folklore than biology.
In reality, we know very little about puma denning behavior due to the difficulty in tracking these wide-ranging animals. As a result, few scientific studies have investigated puma dens, and the best known descriptions are found within the classic book Desert Puma by Logan and Sweanor (2001). Nevertheless, enough published information exists to dispel erroneous assumptions with biology. Here are some observations, along with photos and videos, based on my research of puma dens.
Video: A set of triplet puma kittens nursing in a typical nursery (Video courtesy of Santa Cruz Puma Project)
Contrary to popular belief, pumas do not use permanent dens or lairs. Instead, pumas frequently change where they sleep as they roam throughout their home range hunting and scent marking. In fact, puma dens are more accurately described as nurseries, as they are only used when raising young, immobile kittens. Female pumas are solely responsible for rearing kittens and are the ones that establish and use nurseries. Male puma involvement ends after mating, and males have no other contact with nurseries outside of their natal dens.
Females give birth to 1-4 kittens (Logan and Sweanor 2001) and raise them for about 18 months until they grow large enough to disperse to other areas. Nurseries are integral to the early stages of kittens’ lives, when they are still nursing and not mobile enough to travel. During this period, the mother leaves the nursery to hunt, but frequently returns to nurse the kittens. Once the kittens start eating meat at 3-4 months of age, the mother starts moving them around her home range to different feeding sites.
Video: A mother puma moving her two kittens to a new nursery (Video courtesy of Max Allen)
The most important factor puma mothers consider when choosing the site is likely the safety of their kittens. Other carnivores, including unfamiliar male pumas, are one of the leading causes of mortality for kittens, followed by human activity, often in the form of vehicular accidents. As a result, nurseries tend to be found in areas that are inaccessible to other predators (Elbroch et al. 2015) and as far as possible from human activity and development (Wilmers et al. 2013).
Instead of caves, nurseries are more likely found in thickets, rock piles, or hollow trees. Unlike wolves, bears or other carnivores, pumas don’t have good digging feet, and can’t create hidden nurseries by digging holes in the ground. In my study area in coastal California, puma mothers take advantage of natural barriers, such as thickets of poison oak and stinging nettle, which are generally enough of a deterrence to keep all but the most ardent biologists out.
Nurseries are an ongoing area of my research with the Santa Cruz Puma Project. Keep up to date with our ongoing efforts to understand these elusive felids at https://www.facebook.com/santacruzpumas.
Elbroch, L.M., P. Lendrum, P. Alexander, and H. Quigley. 2015. Cougar den site selection in the Southern Yellowstone Ecosystem. Mammal Research 60:89-96.
Logan, K., and L. Sweanor. 2001. Desert puma: evolutionary ecology and conservation of an enduring carnivore. Island Press: Covelo, CA.
Wilmers, C.C., Y. Wang, B. Nickel, P. Houghtaling, Y. Shakeri, M.L. Allen, J. Kermish-Wells, V. Yovovich, and T. Williams. 2013. Scale dependent behavioural responses to human development by a large predator, the puma. PLoS One 8: e60590.