Pumas Above San Jose


A photo of a puma family above the night time lights of San Jose. This photo was captured with a motion-triggered camera by our field technician Chris Fust. The effects of urbanization and human activity are a focus of our project. We have found that human development affects where pumas choose to have dens and scent marking areas, and also affects how often pumas kill prey.


Using Motion-triggered Cameras To Study Puma Behavior


We have been using motion-triggered video cameras for over 4 years to study puma communication behaviors. Here is a video we captured of a mother puma and two of her playful yearling kittens. We suspect that the mother puma is 52f before we placed a collar on her. For more information on how pumas communicate, see our published paper by Max Allen and Chris Wilmers from 2014.

Three new puma kittens take on the world!

On Saturday, June 20, post-doc Max Allen, technician Chris Fust, and I parked in a grassy field in Wilder Ranch with one mission in mind. We were setting out to visit what we believed to be a newly established den by 25F, a female puma that lives primarily in Wilder. 25F had been present at the den for a few days, so we had waited to go investigate to avoid disturbing her away from her den. Finally, 25F had gone hunting, and we had our chance.

Max, Chris, and I walked across the meadow, through the forest, and down a steep slope as our GPS informed us that we were continuously getting closer. When we were near the den, we split up to try to locate the kittens. Within minutes, Chris had found the den, complete with three nearly 5-week-old kittens. We fitted each one of them with an ear tag for identification purposes and a small, expandable collar that will fall off in a few months. The collar allows us to track their survival in these early and important months of their lives. Find out more about why we collar kittens in an earlier post here.

57M up close

57M up close

59M giving a wave to the camera

59M giving a wave to the camera

These kittens live in a pretty pristine area in Wilder Ranch State Park, but they still face some threats. Puma kittens are sometimes killed by male pumas or other predators. They also need a lot of energy and nutrients, so they rely on their mom to have high hunting success. All three kittens are males, so in about a year and a half, they will have to leave their mom and find their own territories, possibly putting them as risk from crossing roads and freeways.

However, for now, the kittens are healthy, feisty, and safe with their mom. We look forward to following their journeys to adulthood!

58M being fierce

58M being fierce

The Santa Cruz Pumas team with 57M, 58M, and 59M.

The Santa Cruz Pumas team with 57M, 58M, and 59M.

What’s in your fridge?

I am posting this on behalf of project post doc Max Allen, who writes:

This morning I went on a walk and found 3 fresh scats from last night.  Two were from gray foxes and one was from a striped skunk, and all three were choc full of raspberry seeds. I myself had eaten my first raspberry of the spring three days before. On my walk this morning, I found five ripe raspberries. My guess is that the foxes and skunks were able to find many more because they are less picky about ripeness and are more willing to brave the poison oak to find them.

What this brought to mind is how animals rely on seasonal sources of food. Right now, pumas are eating a good number of black-tailed deer fawns. For example, the last 4 of 36M‘s feeding sites that we have investigated have all been fawns. Fawns are an abundant food source this time of year for pumas, and they are likely easier to catch than adult deer. This could be a particularly useful resource for dispersing juveniles, out hunting on their own for the first time, or for females with dependent kittens to feed.


M36 with fawn

Deer fawns are an important seasonal food source for pumas. For more information on seasonal resource use in pumas, check out this recent paper.



The Journeys of Young Pumas, and Welcome to Puma 56M

A young male puma was captured and returned safely to the wilds yesterday by the California Department of Fish and Wildlife and San Mateo Police. As scientists studying pumas, we often receive questions about pumas when this happens. Usually the first questions are “Why does this happen?” and “Is it happening more frequently?” The short answers are “It’s because of puma biology”, and “Probably not”. The reasons behind that require a more detailed explanation.  First…

Some basics about puma biology (we’ll add these facts together later on)

  • Young pumas stay with their mother until they are about 18 months old, in which time they grow from 5 pounds to 70 pounds (females) or 90 pounds (male). Overall, there tend to be equal numbers of male and female cubs born. We’ll say here that a typical female puma is considered an adult at 2 years old, and a male puma is considered an adult at 3 years old, because by those ages they seem to have adopted typical adult behaviors.
  • Pumas can mate any time of year. Because of this, the grown cubs can also leave their mother any time of year. However, in the Santa Cruz Mountains there is a seasonal spike in the birth of puma cubs and a corresponding seasonal spike in cubs that leave their mothers. That spike in dispersing young pumas happens in Spring.

    Puma territories. Large shapes are males. Small shapes are females.San Jose is the gray area at the top.

    Puma territories. Large shapes are males. Small shapes are females.San Jose is the gray area at the top.

  • Adult pumas are territorial. Our GPS collar data shows that male territories in the Santa Cruz Mountains average ~90 square miles, and female territories average ~40 square miles, and a male’s territory will overlap with 3-4 females. Said another way, there are ~3 adult female pumas for every 1 adult male puma.
  • Adult female pumas tolerate young females better than adult male pumas tolerate young males. Young females tend to travel a fairly short distance from where they grew up and form their own territory in a suitable place within just a few months.
  • Adult males – who may weigh 130 pounds and have years of experience – persecute comparatively scrawny young males that are novices and weigh just 95 pounds. It takes 1 or 2 years for a young male to gain the experience and pounds of muscle to maintain his own territory…    …if he can find one. Adult males tend to like remote places with fewer people, which means that the safer places may be closer to people.

Add it up

All of this adds up to create a lengthy journeying phase in the life of young male pumas. They leave their mothers and start to wander in search of a place without an adult male puma and then seek to keep a low profile while they grow in size and experience.

Adult pumas have their territories and don’t venture much outside of them, but these young pumas explore new places. Pumas are stealthy and so they prefer to travel near the cover of forests and brush. Streams and forests are easy places for them to move and look for deer.

Pumas are active mostly at night (which happens to be when people aren’t), and it sometimes happens that a puma follows one of these streams or forests right out of the hills and into a quiet neighborhood at night, only to have it turn into a noisy, busy place of human activity once the sun comes up. So, the puma tries to lay low and find its way back out the next night. Sometimes he can stay unseen for a couple of days. When seen, these pumas aren’t likely acting aggressively. They are more likely waiting for darkness or seeking a way back to the quieter forests. All the cases of young pumas wandering into local cities that we’ve observed involve young males.

It’s a tough road for these young male pumas, and many of them die. In open wilderness such as the Sierra Range or Big Sur, we may expect that adult males would eventually find and kill them. In the Santa Cruz Mountains, however, run-ins with people are frequent causes – the most common being killed by cars while crossing busy roads or being shot for being making an easy meal of small livestock. Still, a few of them get a paw-hold in the more remote forests, find a vacant territory, and survive to adulthood.


56M, recovering and almost ready to continue searching for a territory

Since our research started in 2008, we’ve tracked the dispersal paths of 5 young pumas, including:

Add to that list now 56M – the puma that was caught yesterday in San Mateo. We met with California Department of Fish and Wildlife wardens at the release site and put a GPS tracking collar on him so that we may continue to learn about this important group of young pumas, the young males.

Why are young male pumas so important?

From an animal’s point of view, it’s possible that the Santa Cruz Mountains are cut off from the nearby mountain ranges. Think about it – the mountains west of San Jose, Palo Alto, San Mateo are all surrounded by water: San Francisco Bay, the Pacific Ocean, or Monterey Bay.  There is a narrow area between San Jose, Gilroy, and Watsonville that connects this wonderful mountain range to the rest of North America. But, it’s hard for pumas to move through this area because there are many human influences that pumas stay away from – Highway 101, residential communities, and vast areas dedicated to farming tasty berries in the Salinas Valley.

Since adult pumas have territories that they stay in, and young female pumas tend to move only a few miles from where they are born, it is up to the journeying young males to try and make it across to the neighboring mountain ranges. Can they do it? And, what happens if they can’t?

Part of the Santa Cruz Mountains.  San Jose is the gray area at the top.

Part of the Santa Cruz Mountains. San Jose is the gray area at the top. Can young pumas cross highways, farms, and cities to the nearby mountain ranges?

When animal populations become small in number and isolated from each other, over time relatives begin to breed with each other and strange genetic abnormalities surface that affect the animals. This can make it harder for those affected individuals to survive or they may have fewer cubs, and a spiraling decline can occur. Allowing animals to move between those isolated populations can prevent this, but that takes planning and prioritizing by people amidst our other activities like housing and road construction, farming, and other choices about how land is used.

An important piece of continuing to have pumas in the Santa Cruz Mountains long into the future is to ensure that they stay connected to their neighbors in nearby mountains and do not become isolated. Putting GPS tracking collars on young male pumas can show us if they are able to get through these areas and if they are, where those places are located. So far, none of the males that have tried have made it across. We will continue putting tracking collars on these young pumas to see if – and where – any make it through.

Maybe the San Mateo Puma – 56M – will make it through? Check in with the blog again later. We’ll post an update on his progress.