Although spectacled bears are found in elevations between 250 m and 4,700 m above sea level, throughout a great variety of ecosystems, their preferred habitat is cloud forest (also known as Andean forest) and high Andean moorland called páramo. Cloud forests are found between 1,800 and 3,200 m and páramos from 3,200 to 3,500 m, although they may reach 3,800 m.
These bears can inhabit areas of arid vegetation, with annual rainfall amounting to only 250 mm, as well as tropical jungles with rainfall up to 4,000 mm per year. Bears migrate between forests and páramos in search of ripe fruit and the soft parts of the leaves of certain plants. Mountainous areas containing the whole range of altitudes from cloud forest to páramo make ideal habitats for these animals.
Andean bears are solitary, except for females that are lactating (feeding their offspring with milk) or that are in reproductive period. As in other species of the family, some times male spectacled bears may attack their own cubs when they find them within their home range. However, spectacled bears may occasionally be found in relatively high concentrations, such as when favorite food items are abundant - up to nine wild bears have been recorded foraging together.
Cubs are born with their eyes shut and weigh about 300 g. Eyes are opened after the first month. Cubs are black in colour and already show the white or yellowish 'spectacle' markings, characteristic of the species. The young grow fairly quickly and at 180 days they already weigh 10 kg. Cubs remain with the mother for at least one year after birth. This period of maternal care is fundamental for the cubs to learn to adapt and survive on reaching adulthood.
Bears are estimated to live for just over 20 years, although a captive female lived 36 years.
Pairs are formed only for reproduction between March and October, indicating an ability to reproduce at different times of the year. Bears breed for the first time when they are between four and seven years old. The gestation period oscillates between 160 and 255 days, and a litter contains between one to three cubs. Bears generally give birth during the period September to February.
Bears have an omnivorous diet (they eat both animal and vegetable matter), although they are fairly specialized in fruit and different parts of several plants. They feed high up in trees as well as on plants growing on the ground. When ripe fruit is not available, bears live off fibrous parts of plants such as bromeliad hearts, soft parts of palms, orchid bulbs and even tree bark. Additionally, bears eat insects, small rodents and birds. On some occasions, depending on the scarcity of food, they have been reported to eat deer and cattle, although this is considered to be very sporadic. Bears are even known to be carrion-feeders.