There are folk tales and myths about bears in many cultures. There are several good reasons for this, which are sometimes the same reasons people tell stories about foxes. For example, if you’re not careful, they’ll sometimes steal your food. One night I camped under a full moon in the dry forest with the Bear Specialist Group’s whimsical Ambassador Mi Ton Teiow and the field team of the Spectacled Bear Conservation Society. The sky was clear, so as we set up camp under a sapote tree. We wouldn’t have needed to use a tent except to avoid biting gnats and the slim possibility of fog or mist by morning. Perhaps because we made camp after dark, we mistakenly left a loaf of bread out in the open. By morning, it was gone, no doubt into the belly of a fox. Fortunately, we still had enough food with us that we could continue on and collect data on bear dens, denning habitat, and trees.
In the dry forest it appears that two tree species are important to the local Andean bear population. The fruit of the sapote tree appears to be a critical resource for the bears when it is available from approximately December through February or March, because they focus their foraging on it, and they then dramatically gain weight. When sapote fruit is not available, the bears visibly lose weight, and some of them eat the wood of the pasallo tree, producing feces that look a lot like giant panda feces full of bamboo bits.
Although we began collecting information from sapote trees over a year ago, we haven’t previously collected much information from pasallo trees, as obtaining those data is more challenging. As we began measuring the sizes and densities of pasallo and the other trees growing at higher elevations in the study site, it was surprising for me to realize that two of the most common tree species at these points are considered critically endangered by the government of Peru, as is sapote.
Fortunately, pasallo is not considered at risk of extinction, even in this area where the bears often turn it into wood chips. It’s also been surprising for me to see just how unevenly pasallo is distributed in the landscape. There might be a dense grove of pasallo on one hillside and almost none on the next hillside that otherwise looks very similar. Collecting information from a few hundred more trees should allow us to reach some solid conclusions!
Russ Van Horn is a scientist with the San Diego Zoo Institute for Conservation Research. Read his previous post, Whimsical Bear Ambassador Returns to South America.