not overlap with the spectacled bear in altitude on any specific mountain slope, and only overlaps slightly (900m) in altitude if the entire Cordillera Oriental is considered based upon unpublished data. Generally, the only threat against adult bears is humans. The longest-lived captive bear, at the National Zoo in Washington, DC, in the US, attained a lifespan of 36 years and 8 months. Lifespan in the wild has not been studied, but bears are believed to commonly live to 20 years or more unless they run foul of humans. Spectacled bears are more herbivorous than most other bears; normally about 5 to 7% of their diets is meat. The most common foods for these bears include cactus, bromeliads (especially Puya ssp., Tillandsia ssp. and Guzmania ssp.) palm nuts, bamboo hearts, frailejon (Espeletia spp.), orchid bulbs, fallen fruit on the forest floor, unopened palm leaves, and moss. They will also peel back tree bark to eat the nutritious second layer. Much of this vegetation is very tough to open or digest for most animals, and the bear is one of the few species in its range to exploit these food sources. The spectacled bear has the largest zygomatic mandibular muscles relative to its body size and the shortest muzzle of any living bear, slightly surpassing the relative size of the giant panda's (Ailuropoda melanoleuca) morphology here. Not coincidentally, both species are known for extensively consuming tough, fibrous plants. Unlike the ursid bears whose fourth premolar has a more well-developed protoconid, an adaptation for shearing flesh, the fourth premolar of spectacled bears has blunt lophs with three pulp cavities instead of two, and can have three roots instead of the two that characterize ursid bears. The musculature and tooth characteristics are designed to support the stresses of grinding and crushing vegetation. Besides the giant panda, the spectacled bear is perhaps the most herbivorous living bear species. These bears also eat agricultural products, such as sugarcane (Saccharum ssp.), honey (made by Apis ssp.), and maize (Zea mays), and have been known to travel above the tree line for berries and more ground-based bromeliads. When food is abundant, such as large corn fields, up to nine individual bears have fed close by each other in a single vicinity. Animal prey is usually quite small, but these bears can prey on adult deer, llama (Lama glama) and domestic cattle (Bos taurus) and horses (Equus caballus).