San Diego Zoo researchers are in Peru to study Andean (or spectacled) bears. Read a previous post, Dry-forest Bears of Peru.

It’s early morning, and the cool night air quickly burns away as the sun appears above the ridge of the mountain to the east of the camp. The light that accompanies the heat, however, reveals a spectacular scene. Still in my sleeping bag, I sit up and admire the view. Across a narrow valley, sheer cliffs drop down from the ridge and disappear below. A few somewhat gentler slopes support some vegetation. Javier points out an orange-ish post among the small trees: a posayo tree, reduced to a shattered stump by a foraging Andean (spectacled) bear.

Nearly six months a year, Robyn explains, bears eat these trees. Not their fruits. Not their leaves. They eat the wood. They chew them off at the base, fashioning themselves after beavers, topple the tree, and spend the next few days or weeks eating wood pulp. And pooping wood pulp.

Such are the extremes to which a dry-forest bear must go to sustain itself during the dry season. But they appear to thrive on it. How they manage to extract enough energy and nutrients from these trees is a mystery. Fortunately, bears experience more plentiful, and typical, bounty in the wet season when the sapote trees fruit. Then the bears descend to the bottom of the mountains and feed, often just a few hundred meters from human dwellings. These are the few, the essential, resources on which the bear largely depends—water holes, posayo trees, and sapote fruits. At least two of these resources place the bears in a vulnerable position, at the mercy of nearby human communities. If people were, for example, to expand their villages and farms to the base of the mountains, they may drive the bears away from the sapote trees or, worse, cut the trees down. If they brought goats or cattle to the waterholes, this too could prove disastrous for the bears and other wildlife.

Our camp is ideally situated for bear viewing. Amazingly, bears regularly descend these rock walls of the opposing cliffs to a waterhole at the bottom. This is a feat that has to be seen to be believed. All day we scan the cliffs for signs of bear. We spot a few more posayo trees that have been recently dismantled by bears. José traverses the slopes to inspect a cave where last year a female gave birth to a cub. No luck. The bears are around, but we don’t see them.

Then, just before dusk, Javier spots a dark object moving quickly down a steep rocky slope. Through my binoculars, finally, I see the bear—a large male descending headfirst, with the apparent ease of a Sunday stroll. Moments later he disappears into the bowels of the canyon where the life-giving water can be found. Tomorrow morning, we hope, we will see him ascend back up the cliffs and find a posayo tree on which to dine.

Ron Swaisgood is the director of Applied Animal Ecology for the San Diego Zoo’s Institute for Conservation Research.

Posted in Bear Awareness, Conservation, Default, Field Studies, General | Link to this post

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