Feeding Ecology

Andean bears are true arboreal bears, using their long, sharp front claws to climb trees and large rock cliffs. They build leafy platforms in the trees or on cliff ledges, which they may use as day time or night time beds. The bears are mainly plant eaters, dining on fruit, bromeliads, cactus and trees such as the pasallo tree.

sapote fruit Bears use plant foods according to their seasonal availability. The single-most important food for bears in the equatorial dry forest is the fruit of the sapote tree, a sweet, avocado-textured fruit, 10 cm x 5 cm in size that is produced in abundance on trees averaging 2 – 4 m in height at maturity. Sapote is abundant at elevations ranging from 200 – 500m, but ripening varies with elevation, starting in late November at low elevations. The first scats we found containing sapote seeds were in December, 2006, approximately 1 week after the ripening of the first low elevation fruits.

While feeding on Sapote, bears used well-established trail networks to access each of the Sapote trees, walking from plant to plant, pulling down branches, and plucking fruit. Often, feeding resulted in broken branches in the tree canopy; these dead branches persisted for months as tell-tale signs of bear feeding activity. Bears typically consumed fruit a few meters from the tree. They fed for 1-6 minutes at each tree, and moved from tree to tree, often across a number of valleys in the same day. We found no evidence in scats or behavior suggesting that bears were feeding on any other types of food during this time. When feeding on Sapote fruit, the bears we observed travelled greater daily distances than when feeding on foods at higher elevations, despite the much higher temperatures than at other times of year. This is because they moved to lower elevations to feed and returned to higher elevations during the day to drink or bath at water holes and for mid-day rest periods. They also retreated most nights to cliff ledges at elevations of 600 – 1100 m. As low-elevation fruits passed their prime and fruits higher on the mountain slopes ripened, bears likewise fed at increasingly higher elevations, reaching the highest sapotes at about 300 – 500 m in late April.

When the Sapote plants finish producing fruit, bears move to high elevations (600 – 1000 m), where pasallo trees are abundant on the rocky hillsides and cliff ledges. Wood from the trunks of the pasallo, in particular the core wood, was the staple food item of bears during the fall, winter, and spring months of late April – late November. On several occasions, we watched as bears appeared to sample several trees of different sizes before feeding on a particular tree. After taking a bite through the bark of the tree, the bear decided to either continue feeding on that tree or move on to sample another tree. Once a “suitable” tree was located, the bear used tremendous force to rip through the outer bark and feed on the wood inside. We watched bears on a number of occasions tearing large pieces of wood from the tree and sucking it by holding it between the front paws. Bears fed on trees to the point of destruction, sometimes over multiple days. Females pulled off pieces of pasallo core wood for her cubs to feed on a few meters away while she worked over the main trunk. In addition to pasallo, bears also periodically fed on land snails, cactus, honey bee hives, overo, and vichayo fruits, as well as some insects during this time.


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