Fast Facts

Length:88– 206 cm
Weight:34–175 kg
Lifespan:35 years (captivity)
Distribution:Andean mountain range of Venezuela, Colombia, Ecuador, Peru, and Bolivia
Status:Vulnerable (IUCN)
Appendix I (CITES)


Species:Tremarctos ornatus

Common Names

Spanish:Oso Andino, oso de anteojos, oso frontino, oso real
English:Andean bear, spectacled bear
French:Ours à lunettes, ours andin
Local:Jucumari, ucumari, ucumar, ucu


The Andean bear, or spectacled bear, is the largest carnivore of the Tropical Andes and the only bear species in South America [1]. It is a medium-sized bear, with adult weight ranging from 34 to 175 kg and body length from 88 to 206 cm [2]. Males are usually one third larger than females. The dense coat is black to brown in colour, although some individuals with a reddish tinge have been identified. Facial patterns of white to yellowish marks that usually occur around the eyes are characteristic of the species and are the reason it is often known as the spectacled bear. These marks may extend under the chin and across the throat onto the chest, are known to be highly variable, may change in shape and colour with age, and in some individuals may be absent altogether [1]. As a characteristic of the subfamily Tremarctinae, or short-faced bear, Andean bears have massive skulls compared to other omnivore bear species and their snout is relatively short compared to that of other bear species. They have strong jaw muscles for crushing and grinding tough fibrous food such as bromeliads, palms, and bamboo. Similar to the giant panda, Andean bears have a false thumb that might play an important role in food manipulation [3].


Total length (cm)
BodyTailWeight (kg)

a [2]; b [4]; c [5] 

Sexual dimorphism: Males are usually one third larger than females.


Andean bears are diurnal, and unlike other bear species they do not hibernate. Generally solitary, this species can occasionally be seen feeding in small groups where food is plentiful. Mainly terrestrial, Andean bears have developed a highly arboreal lifestyle, which is important for feeding, resting, and escaping danger [1, 6]. Tree nests are built to serve multiple behavioural purposes and are used for feeding on fruit or carcasses and for resting or guarding feeding sites [1, 7, 8]. Very little is known regarding communication behaviour, but field observations indicate that this species scent-marks trees, which could represent a means of communication among adult bears [6, 8], whereas auditory calls occur mainly between mother and cub [6, 9, 10]. Although the Andean bear is omnivorous, vegetative matter forms the majority of its diet, in particular the hard and fibrous bromeliads, palms, and bamboo. The bears feed year round on these fibrous plant species; however, they depend on fruits and other more nutritional food items such as bark from trees, rodents, birds, and insects to obtain the necessary nutrients to survive [11]. They also occasionally prey on livestock [11]. Mating may occur throughout the year and as in other bear species, the length of gestation is highly variable and difficult to calculate because of delayed implantation. Births occur about 6 weeks prior to the fruit-ripening period, with litter size possibly correlated to female body condition and habitat quality [1, 12, 13]. Per ex situ observations (A.E. Bracho, personal communication), females give birth in a den and remain there from 3 to 4 months. Maternal care may last up to 2 years [14–16; A.E. Bracho, personal communication]. Predators of spectacled bear cubs may include pumas (Puma concolor), jaguars (Panthera onca), and adult male bears. In captivity, females spectacled bears may live for up to 35 years, while males have being reported to reach 36 to 40 years of age [17].

Reproduction and lifespan

Gestation (months)Maximum litter sizeLifespan (yearsr)
JuvenileAdultMaximum age
6.5 – 8.5a310–2b3–7b, c35c

a [18]; b [19]; c [17]

Mating system: Polygynous
Breeding interval: Once per year
Breeding season: March to October
Independence: Up to 2 years

Population Status

Regional and continental population estimates are lacking for Andean bears. In 1998, Peyton generated a rough estimation of >20,000 Andean bears by extrapolating densities of American black bears (Ursus americanus) to the geographic range of Andean bears. In recent years, genetic techniques have been used to obtain population estimates for Venezuela, Colombia, and Ecuador. These efforts have resulted in population estimates of 1,100–1,600 bears for Venezuela [20], 3,000–6,000 for Colombia [20], 1,200–2,000 for Ecuador [21, 22], and about 5,000 breeding bears in Peru [20]. In Bolivia, the application of ecological models and GIS has resulted in an estimate of more than 3,000 adult bears [23].

Population estimates

Continental> 20,000a
Ecuador1,200 – 2,000d
Colombia3,000 – 6,0003
Venezuela1,100 – 1,600c

a [24]; b [23]; c [20]; d [21, 22];

Adult bears

Distribution and Range

Endemic to the Tropical Andes [5], the Andean bear inhabits the mountain regions of Venezuela, Colombia, Ecuador, Peru, and Bolivia. The presence of the species in Argentina has been considered possible, but evidence is inconclusive and controversial [25–28]. In terms of extent, the area occupied is about 4,600 km by 200–650 km [29]. The altitudinal range of the species extends from as high as 4,750 m above sea level in Bolivia down to 200 m elevation in Peru [30, 31].

Geographic range



Bears in general have the reputation for being adaptable species, and the Andean bear is a clear example of this plasticity. The species occupies lowland, sub-montane, and montane deciduous, semi-deciduous, and evergreen forests, moors, páramos, puna grasslands, and even coastal deserts to the northwest of the Peruvian Andes [1, 15, 29, 32–35]


Home Range

Information regarding home range size is scarce and estimates include speculative values based on other bear species, weighted home range ratios, and data gathered from a small number of reintroduced and wild Andean bears. According to Castellanos [6; Castellanos, personal communication], females have smaller home ranges than males. Extensive home range overlap has been found, especially between females and males [2, 6, 36]. Paisley [2] reported a mean daily movement of about 800 m, with a maximum movement of >6 km, while Castellanos (personal communication) found daily movements of up to 3–4 km. Greater movements and larger home ranges have been reported during the rainy season [2].

Home range size

RegionHome range size (km2)
Intag, Ecuadora51a†59a†
Maquipuna Biological Reserve, Ecuadorb4.1b61b
Apolobamba, Boliviac16,377–9c

a [37]; b [36]; c [2]
Annual home range


Andean bears are omnivores with a preference towards vegetative matter (up to 90% of their diet). Bromeliads and palm trees are considered the common food item in their range that is available all year round, whereas the consumption of fruits is restricted to few weeks out of the year. Animal protein is consumed opportunistically, and attacks on domestic animals [31] as well as raiding of agricultural crops have being reported. These behaviours have led to human–bear conflicts, which usually results in retaliatory poaching [38].

The following is a comprehensive list of food items [31].


ClassificationPlant source (%)Animal source (%)Main food items
ApiaceaeEryngium nudicaule
BromeliaceaeGregia, Guzmania, Puya, Tillandsia
CactaceaeOpuntia, Trichocereus
DicksoniaceaeDicksonia sellowiana
EricaceaePernettya prostrata, Gaultheria, Schinus, Vaccinium
LauraceaeNectandra cuneatocordata
PoaceaeBambusa, Chusquea, Guadua
RosaceaeRubus, Hesperomeles ferruginea, H. lanuginosa, Prunus brittianus
SymplocaceaeSymplocos cernua
Annelida, Coleoptera, Dermaptera, Diptera, Hymenoptera, Isoptera, Orthoptera
Artiodactyla, Carnivora, Cingulata, Lagomorpha, Perissodactyla, Pilosa, Rodentia

Conservation Status

The Andean bear is classified as Vulnerable on the IUCN Red List. Based on the current state of the Andean bear’s habitat, the fact that many threats causing reduction and degradation of Andean bear ecosystems are ongoing, and projected patterns of biodiversity shift caused by climate change, it is likely that the species will remain in the Vulnerable criteria through the year 2030 [40]. Patches large enough to sustain viable Andean bear populations have been reduced nearly 30% within the past 20 years. Habitat loss has continued and projections for 2010–2039 show all ecosystems inhabited by Andean bears will exhibit some degree of loss [39].

The Andean bear has been listed since 1973 as Vulnerable by Red List of Threatened Species (IUCN) and included in Appendix I of CITES since 1977. Hunting bans have been declared at the national levels across the species’ distribution, but these regulations are ineffective, and legislation is not enforced so poaching activities continue [30, 40, 41]. Protected bear habitat—parks, reserves, and sanctuaries—still cover a minimal area (<20%) compared to the bear’s range. Furthermore, many protected areas may be inadequate, too small, or too isolated to support viable bear populations [30, 41, 42].

Studies on the distribution, frequency, and intensity of human–bear conflicts have been carried out in some areas in order to better understand these situations and thereby develop management measures, in order to reduce conflicts and the consequent killing of bears [44]. Management plans to reduce bear–cattle conflicts have been developed at Oyacachi, Ecuador, based on predation probability models [44].

Workshops have been conducted in several of the range countries to train researchers and personnel from national parks on survey techniques, development of habitat models, and general knowledge about the ecology, distribution, and status of the species. An Ecorregional Strategy was developed for the species conservation across the Northern Andes, and national action plans have been also developed in Venezuela, Colombia, and Ecuador [28, 37, 42, 45–47].


Habitat loss, degradation, and fragmentation are the main threats for Andean bear populations [25, 30, 48]. Agricultural expansion prompted by agrarian reforms and farming practices (such as monocultures, slash and burn, shifting cultivation, and extensive highland grazing) have considerably reduced Andean bear habitats [40]. Poaching, including the pet trade, is also a significant threat for the species [24, 34, 43]. The impact of this threat, however, remains to be estimated accurately. Crop raiding and feeding on livestock are main drivers of poaching [38]. Jorgenson and Sandoval [43] reported 34 bear kills from 36 corn-raiding and 26 cattle-eating events between 1992 and 1997. Bear parts are also widely shared by local people, and sales appear to be mainly restricted to country borders and localized within them, although no detailed information is currently available [1, 2, 30, 31, 34, 43].

Andean Bears and Humans

Andean bears possess great mythological and ritual importance for native peoples who share their range [2]. They are a flagship species given their charismatic nature, so they can act as an umbrella for the protection of Andean biodiversity. They are a keystone species, as they play a major role in maintaining the dynamics of the cloud forest ecosystem they live in. However, some human communities consider Andean bears to be a nuisance or even a plague given crop raiding and cattle predation.


Ximena Velez-Liendo, PhD
Chester Zoo Conservation Fellow. WildCRU, Department of Zoology, University of Oxford, UK


  1. Peyton, B. 1980. Ecology, distribution, and food habits of Spectacled Bears, Tremarctos ornatus, in Peru. Journal of Mammalogy 614:639–652. doi: 10.2307/1380309
  2. Paisley, S. 2001. Andean bears and people in Apolobamba, Bolivia: culture, conflict and conservation. Ph.D. dissertation, University of Kent, Canterbury, UK.
  3. Salesa, M.J., G. Siliceo, M. Anton, J. Abella, P. Montoya, and J. Morales. 2006. Anatomy of the ‘false thumb’ of Tremarctos ornatus (Carnivora, Ursidae, Tremarctinae): phylogenetic and functional implications. Estudios Geológicos 62(1):389–394. doi: 10.3989/egeol.0662133
  4. Macdonald, D.W., ed. 2007. The Encyclopedia of Mammals, 3rd ed. Oxford Reference, Oxford University Press. Available at: doi: 10.1093/acref/9780199206087.001.0001
  5. Emmons, L.H. 1997. Neotropical rainforest mammals: a field guide. University of Chicago Press, Chicago, Illinois, USA.
  6. Castellanos, A. 2008. Andean bear conservation project: project results. Fundación Espíritu del Bosque, Quito, Ecuador, Quito, Ecuador.
  7. Goldstein, I.R. 2002. Andean bear-cattle interactions and tree nest use in Bolivia and Venezuela. Ursus, 13:369–372.
  8. Eulert, C. 1995. Evaluación del estado actual del jucumari Tremarctos ornatus en el Parque Nacional Amboro, Santa Cruz Bolivia. Ph.D. dissertation, Universidad Autónoma Gabriel Rene Moreno, Santa Cruz, de la Sierra, Bolivia.
  9. Garshelis, D.L., and L. G. Visser. 1997. Enumerating megapopulations of wild bears with an ingested biomarker. The Journal of Wildlife Management 61:466–480. doi: 10.2307/3802605
  10. Garshelis, D.L. 2009. Family Ursidae (Bears). Pages 448–497 in D.E. Wilson and R.A. Mittermeier, eds. Handbook of the mammals of the world. Volume 1. Carnivores. Lynx Edicions, Barcelona, Spain.
  11. Garcia-Rangel, S. 2010. Ecology and conservation of the Andean bear in Venezuela. Ph.D. dissertation, University of Cambridge, Cambridge, UK.
  12. Hilderbrand, G.V., C.C. Schwartz, C.T. Robbins, M.E. Jacoby, T.A. Hanley, S.M. Arthur, and C. Servheen. 1999.  The importance of meat, particularly salmon, to body size, population productivity, and conservation of North American brown bears. Canadian Journal of Zoology 77:132–138. doi: 10.1139/z98-195
  13. Derocher, A.E., and I. Stirling. 1998. Maternal investment and factors affecting offspring size in polar bears (Ursus maritimus). Journal of Zoology 245(3):253–260. doi: 10.1111/j.1469-7998.1998.tb00099.x
  14. Paisley, S., and D.L. Garshelis. 2005. Activity patterns and time budgets of Andean bears (Tremarctos ornatus) in the Apolobamba Range of Bolivia. Journal of Zoology 268:25–34. doi: 10.1111/j.1469-7998.2005.00019.x
  15. Mondolfi, E. 1989. Notes on the distribution, habitat, food habits, status and conservation of the spectacled bear (Tremarctos ornatus Cuvier) in Venezuela. Mammalia 53(4):525–544. doi: 10.1515/mamm.1989.53.4.525
  16. Sun, Pei. 2004. The effect of early rearing experience on adult reproductive behavior in captive giant pandas and spectacled bears. Georgia Institute of Technology, Atlanta, USA.
  17. Rosenthal, M.A., and D. Weinhardt. 1986. International studbook for the spectacled bear (Tremarctos ornatus). Lincoln Park Zoological Gardens, Chicago Park District Press, Chicago, Illinois, USA.
  18. Nowak, R.M. 2005. Walker´s carnivores of the world. The John Hopkins University Press, Baltimore, Maryland, USA.
  19. Rodriguez-Clark, K.M., and A. Sanchez Mercado. 2006. Population management of threatened taxa in captivity within their natural ranges: lessons from Andean bears (Tremarctos ornatus) in Venezuela. Biological Conservation 129:134–148. doi: 10.1016/j.biocon.2005.10.037
  20. Ruiz-Garcia, M. 2003. Molecular population genetic analysis of the spectacled bear (Tremarctos ornatus) in the northern Andean area. Hereditas 138:81–93. doi: 10.1034/j.1601-5223.2003.01578.x
  21. Viteri, M.P. 2007. Conservation genetics of Andean bears (Tremarctos ornatus) in northeastern Ecuador: molecular tools, genetic diversity and population size. Ph.D. dissertation, University of Idaho, Idaho, USA.
  22. Diego Tirira, S. 2001. Lista roja de los mamíferos del Ecuador. Page 4 in Libro rojo de los mamíferos del Ecuador. SIMBIOE/EcoCiencia, Quito, Ecuador.
  23. Velez-Liendo, X. 2010. Conservation of Andean bears (Tremarctos ornatus) in a fragmented landscape: habitat models, potential distribution and patch connectivity. Ph.D. dissertation, University of Antwerp, Antwerp, Belgium.
  24. Peyton, B., E. Yerena, D.I. Rumiz, J. Jorgenson, and J. Orejuela. 1998. Status of wild Andean bears and policies for their management. Ursus 10:87–100. Available at:
  25. Goldstein, I., X. Velez-Liendo, S. Paisley, and D.L. Garshelis. 2008. Tremarctos ornatus. IUCN Red List of Threatened Species. Version 2010.4. IUCN, Glad, Switzerland, and Cambridge, UK. Available at:
  26. Rumiz, D.I., A.D. Brown, P.G. Perovic, S.C. Chalukian, G.A. Erica Cuyckens, P. Jayat, F. Falke, and D. Ramadori. 2012. El ucumar (Tremarctos ornatus), mito y realidad de su presencia en la Argentina. Mastozoología neotropical 19(2):359–366. Available at:
  27. Díaz, M.M., J.K. Braun, M.A. Mares, and R.M. Bárquez. 2000. An update of the taxonomy, systematics, and distribution of the mammals of Salta province, Argentina. Occasional Papers of the Oklahoma Museum of Natural History 10:1–52. Available at:
  28. Cosse, M., J.F. Del Moral Sachetti, N. Mannise, and M. Acosta. 2014. Genetic evidence confirms presence of Andean bears in Argentina. Ursus 25(2):163–171. doi: 10.2192/URSUS-D-14-00020.1
  29. Kattan, G., O.L. Hernández, I. Goldstein, V. Rojas, O. Murillo, C. Gómez, H. Restrepo, and F. Cuesta. 2004. Range fragmentation in the spectacled bear Tremarctos ornatus in the northern Andes. Oryx 38:155–163. doi: 10.1017/S0030605304000298
  30. Peyton, B. 1999. Spectacled bear conservation action plan. Pages 157–164 in C. Servheen, S. Herrero, and B. Peyton, B., eds. Bears: status survey and conservation action plan. IUCN Red List of Threatened Species. International Union for the Conservation of Nature, Gland, Switzerland. Available at:
  31. García-Rangel, S. 2012. Andean bear Tremarctos ornatus natural history and conservation. Mammal Review 42(2):85–119. doi: 10.1111/j.1365-2907.2011.00207.x
  32. Goldstein, D.B., G.W. Roemer, D.A. Smith, D.E. Reich, A. Bergman, and R.K. Wayne. 1999. The use of microsatellite variation to infer population structure and demographic history in a natural model system. Genetics 151:797–801.
  33. Cuesta, F., M.F. Peralvo, and F.T. Van Manen. 2003. Andean bear habitat use in the Oyacachi River Basin, Ecuador. Ursus 14:198–209.
  34. Figueroa, J., and M. Stucchi. 2009. El Oso Andino: alcances sobre su historia natural. Asociación para la Investigación y Conservación de la Biodiversidad (AICB), Lima, Peru.
  35. Appleton, R., J. Guerrero, and S. Paisley. 2007. Mark-resight population estimates derived from observations of Andean bears using water holes in the tropical dry forests of Peru. The 18th International Conference on Bear Research & Management. International Association for Bear and Research Management.
  36. Castellanos, A.X., M. Altamirano, and G. Tapia. 2001. Ecology and behaviour of reintroduced Andean Bears in the Biological Reserve Maquipucuna, Ecuador: implications in conservation. Available at:
  37. Castellanos, A. 2011. Andean bear home ranges in the Intag region, Ecuador. Ursus 22(1):65–73. doi: 10.2192/URSUS-D-10-00006.1
  38. Can, Ö.E. N. D’Cruze, D.L. Garshelis, J. Beecham, and D.W. Macdonald. 2014. Resolving human–bear conflict: a global survey of countries, experts, and key factors. Conservation Letters 7(6):501–513. doi: 10.1111/conl.12117
  39. Tovar, C., C.A. Arnillas, F. Cuesta, and W. Buytaert. 2013. Diverging responses of tropical Andean biomes under future climate conditions. PLoS One 8(5):2013. doi: 10.1371/journal.pone.0063634
  40. Velez-Liendo, X., and S. García-Rangel. 2017. Tremarctos ornatus. The IUCN Red List of Threatened Species 2017: e.T22066A45034047. doi: 10.2305/IUCN.UK.2017-3.RLTS.T22066A45034047.en
  41. Velez-Liendo, X. 1999. Caracterización y uso de hábitat del oso Andino Tremarctos ornatus en la zona de la Yunga Alta de los ríos San Jacinto, Raso y Málaga del Departamento de Cochabamba. Universidad Mayor de San Simon, Cochabamba, Bolivia.
  42. Yerena, E., D.M. Dam, D.A. Torres, A. Sánchez, S. García-Rangel, A.E. Bracho, Z. Martínez, and I. Gómez. 2007. Plan de acción para la conservación del oso andino (Tremarctos ornatus) en Venezuela (2006–2016). Merida: Fundación AndígenA, FUDENA. Available at:

43       Jorgenson, J.P., and A.S. Sandoval. 2005. Andean bear management needs and interactions with humans in Colombia. Ursus 16:108–116. 10.2192/1537-6176(2005)016[0108:ABMNAI]2.0.CO;2

44       Goldstein, I., S. Paisley, R. Wallace, J.P. Jorgenson, F. Cuesta, and A. Castellanos. 2006. Andean bear-livestock conflicts: a review. Ursus 17:8–15. 10.2192/1537-6176(2006)17[8:ABCAR]2.0.CO;2

45       Helgen, K., J. Maldonado, D. Wilson, and S. Buckner. 2008. Molecular confirmation of the origin and invasive status of West Indian raccoons. Journal of Mammalogy 89(2):282–291. doi: 10.1644/07-MAMM-A-155R.1

46       Rodriguez, D., F. Cuesta, I. Goldstein, L. Naranjo, and O. Hernández. 2003. Estrategia ecorregional para la conservación del oso andino–Tremarctos ornatus–en los Andes del Norte (page 38). World Wildlife Fund, Colombia.

47       Ministerio Del Medio Ambiente. 2001. Programa Nacional Para La Conservación En Colombia Del Oso Andino (page 27). Ministerio del Medio Ambiente, Bogotá, Colombia.

48       Rodriguez, A., and M. Delibes. 2003. Population fragmentation and extinction in the Iberian lynx. Biological Conservation 109:321–331.