Temporal range: Holocene
|A spectacled bear in Tennōji Zoo, Osaka.|
|Spectacled bear range|
Ursus ornatus Cuvier, 1825
The spectacled bear (Tremarctos ornatus), also known as the Andean bear or Andean short-faced bear and locally as jukumari (Aymara), ukumari (Quechua) or ukuku, is the last remaining short-faced bear (subfamily Tremarctinae) and its closest relatives are the extinct Florida spectacled bear, and the giant short-faced bears of the Middle Pleistocene to Late Pleistocene age. Spectacled bears are the only surviving species of bear native to South America, and the only surviving member of the subfamily Tremarctinae.
The spectacled bear is the only bear native to South America and is technically the largest land carnivore on that continent, although as little as 5% of its diet is composed of meat. South America's largest obligate carnivorous mammal is the jaguar (Panthera onca). Among South America's extant, native land animals, only the Baird's (Tapirus bairdii) and South American tapirs (T. terrestris) are heavier than this species. The spectacled bear is a mid-sized species of bear. Overall, its fur is blackish in color, though bears may vary from jet black to dark brown and to even a reddish hue. The species typically has distinctive beige or ginger-coloured markings across its face and upper chest, though not all spectacled bears have "spectacle" markings. The pattern and extent of pale markings are slightly different on each individual bear, and bears can be readily distinguished by this. Males are a third larger than females in dimensions and sometimes twice their weight. Males can weigh from 100 to 200 kg (220 to 440 lb), and females can weigh from 35 to 82 kg (77 to 181 lb). Head-and-body length can range from 120 to 200 cm (47–79 in), though mature males do not measure less than 150 cm (59 in). The tail is a mere 7 cm (2.8 in) in length, and the shoulder height is from 60 to 90 cm (24–30 in). Compared to other living bears, this species has a more rounded face with a relatively short and broad snout. In some extinct species of the Tremarctinae subfamily, this facial structure has been thought to be an adaptation to a largely carnivorous diet, despite the modern spectacled bears' herbivorous dietary preferences.
Distribution and habitat
Despite some rare spilling over into eastern Panama, spectacled bears are mostly restricted to certain areas of northern and western South America. They can range in western Venezuela, Colombia, Ecuador, Peru, western Bolivia, and northwestern Argentina. The species is found almost entirely in the Andes Mountains. Before spectacled bear populations became fragmented during the last 500 years, the species had a reputation for being adaptable, as it is found in a wide variety of habitats and altitudes throughout its range, including cloud forests, high-altitude grasslands, dry forests and scrub deserts. A single spectacled bear population on the border of Peru and Ecuador inhabited as great a range of habitat types as the world's brown bears (Ursus arctos) now occupy. The best habitats for spectacled bears are humid to very humid montane forests. These cloud forests typically occupy a 500 to 1,000 m (1,600 to 3,300 ft) elevational band between 1,000 and 2,700 m (3,300 and 8,900 ft) depending on latitude. Generally, the wetter these forests are the more food species there are that can support bears. Occasionally, they may reach altitudes as low as 250 m (820 ft), but are not typically found below 1,900 m (6,200 ft) in the foothills. They can even range up to the mountain snow line at over 5,000 m (16,000 ft) in elevation.
Naming and etymology
Tremarctos ornatus is commonly referred to in English as the "spectacled bear", a reference to the light colouring on its chest, neck and face, which may resemble eyeglasses in some individuals, or the "Andean bear" for its distribution along the Andes.
The root trem- comes from a Greek word meaning "hole;" arctos is the Greek word for "bear." Tremarctos is a reference to an unusual hole on the animal's humerus. Ornatus, Latin for "decorated", is a reference to the markings that give the bear its common English name.
Behavior and diet
Spectacled bears are one of the half of extant bear species that are habitually arboreal, alongside the American (Ursus americanus) and Asian black bears (U. thibetanus) and the sun bears (Helarctos malayanus). In Andean cloud forests, spectacled bears may be active both during the day and night, but in Peruvian desert are reported to bed down under vegetative cover during the day. Their continued survival alongside humans has depended mostly on their ability to climb even the tallest trees of the Andes. They usually retreat from the presence of humans, often by climbing trees. Once up a tree, they may often build a platform, perhaps to aid in concealment, as well as to rest and store food on. Although spectacled bears are solitary and tend to isolate themselves from one another to avoid competition, they are not territorial. They have even been recorded to feed in small groups at abundant food sources. Males are reported to have an average home range of 23 km2 (8.9 sq mi) during the wet season and 27 km2 (10 sq mi) during the dry season. Females are reported to have an average home range of 10 km2 (3.9 sq mi) in the wet season and 7 km2 (2.7 sq mi) in the dry season. When encountered by humans or other spectacled bears, they will react in a docile but cautious manner, unless the intruder is seen as a threat or a mother's cubs are endangered. Like other bears, mothers are protective of their young and have attacked poachers. There is only a single reported human death due to a spectacled bear, which occurred while it was being hunted and was already shot. The only predators of cubs include cougars (Puma concolor) and possibly male spectacled bears. The bears "appear to avoid" jaguars, but the jaguar has considerably different habitat preferences, does 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, 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 afoul 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, and unopened palm leaves. 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, fiberous 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 has 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 cultivated plants, such as sugarcane (Saccharum ssp.), honey (made by Apis ssp.), and corn (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 primigenius taurus) and horses (Equus ferus caballus). Animal prey has included rabbits, mice, other rodents, birds at the nest (especially ground-nesting birds like tinamous or lapwings (Vanellus ssp.)), arthropods, and carrion. They are occasionally accused of killing livestock, especially cattle, and raiding corn fields. Allegedly, some bears become habituated to eating cattle, but the bears are actually more likely to eat cattle as carrion and some farmers may accidentally assume the spectacled bear killed them. Due to fear of loss of stock, bears may be killed on sight.
Mating may occur at almost any time of the year, but activity normally peaks in April and June, at the beginning of the wet season and corresponding with the peak of fruit-ripening. The mating pair are together for one to two weeks, during which they will copulate multiple times. Births usually occur in the dry season, between December and February. The gestation period is 5.5 to 8.5 months. From one to three cubs may be born, with four being rare and two being the average. The cubs are born with their eyes closed and weigh about 300 to 330 g (11 to 12 oz) each. Although this species does not give birth during the hibernation cycle as do northern bear species, births usually occur in a small den and the female waits until the cubs can see and walk before she leaves with them. The size of the litter has been positively correlated with both the weight of the female and the abundance and variety of food sources, particularly the degree to which fruiting is temporally predictable. The cubs often stay with the female for one year before striking out on their own. Breeding maturity is estimated to be reached at between four and seven years of age for both sexes, based solely on captive bears.
The spectacled bear population is under threat for a number of reasons. Unfortunately, still no species-level conservation efforts are known to exist for spectacled bears. Each government has made differing commitments to conservation in this species range, with Venezuela, thanks to its relatively high level of scientific industry and relatively stable economy being the most advanced at bear conservation to Colombia, where the species and its habitats are largely unprotected. The bears are hunted by locals due to a belief they will eat livestock (although spectacled bears do not normally eat large quantities of meat). Their gall bladders are also valued in traditional Chinese medicine and can fetch a high price on the international market. Perhaps the most epidemic problem for the species is extensive logging and farming, which has led to habitat loss for the largely tree-dependent bears. As little of 5% of the original habitat in Andean cloud forest remains. As the bear's food sources have been disappearing, it relies on crops for food. So, farmers see the bears as competition and hunt them. Legislation against hunting the bears exists, but is rarely enforced. The IUCN has recommended the following courses for spectacled bear conservation: expansion and implementation of conservation land to prevent further development, greater species level research and monitoring of trends and threats, more concerted management of current conservation areas, stewardship programs for bears which engage local residents and the education of the public regarding spectacled bears, especially the benefits of conserving the species due to its effect on natural resources.
In the documentary Paddington Bear: The Early Years, British actor Stephen Fry encounters a spectacled bear called Yogi, which was kept in a small cage by Andean villagers (see also Paddington Bear). Fry bartered with the villagers to have the bear released, and it was taken to an enclosure in Machu Picchu. Fry's interest in the bears led to the follow-up documentary, Stephen Fry and the Spectacled Bears, and he also wrote and published his experiences in Rescuing the Spectacled Bear: A Peruvian Diary.
In the BBC television programme Serious Andes, a team of eight teenagers built a prerelease enclosure for two spectacled bears before returning them to the wild. The BBC documentary "Spectacled Bears: Shadows of the Forest" looks at some of the bear research being done in Peru and Ecuador and what the researchers are discovering.
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