Body length: 88 to 206 cm
Average weight: 34 to 175 kg
Lifespan: 35 years (captivity)
Distribution: Andean mountain range of Venezuela, Colombia, Ecuador, Peru, and Bolivia
Status: Vulnerable (IUCN), Appendix I (CITES)
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Ursidae
Subfamily: Tremarctinae
Genus: Tremarctos
Species: Tremarctos ornatus Cuvier 1825
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 | Tail | Body mass | |
|---|---|---|---|
| Subadult | 88-119a | N/A | 30-56a |
| Adult ♂ | 130-200b | N/A | 140-175b |
| Adult ♀ | 112-220c | 7-7.53 | 80-175c |
Length measurements in cm and mass in 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].
| Gestation (weeks) | Maximum litter size | Juvenile lifespan (years) | Adult lifespan (years) | Maximum age (years) |
|---|---|---|---|---|
| 6.5-8.5a | 31 | 0-2b | 3-7b,c | 35c |
a [18]; b[19]; c[17]
Mating system: Polygynous
Breeding interval: Once per year
Breeding season: March to October
Independence: Up to 2 years
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].
| Countries and Regions | Population Size |
|---|---|
| South America | >20,000a |
| Bolivia | 3,000b* |
| Peru | 5,000c* |
| Ecuador | 1,200-2,000d |
| Columbia | 3,000-6,0003 |
| Venezuela | 1,100-1,600c |
a[24]; b[23]; c[20]; d[21, 22]
* Adult bears
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].
Green = Extant. Map data courtesy of IUCN Redlist.
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].
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].
| Region | Females | Males |
|---|---|---|
| Intag, Ecuadora | 51a* | 59a* |
| Maquipuna Biological Reserve, Ecuadorb | 4.1b | 61b |
| Apolobamba, Boliviac | N/A | 7-9c |
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]:
| Category | Main food items |
|---|---|
| Plants | Agavaceae: Agave, Apiaceae: Eryngium nudicaule, Asparagaceae: Furcraea, Bromeliaceae: Gregia, Guzmania, Puya, Tillandsia, Cactaceae: Opuntia, Trichocereus, Dicksoniaceae: Dicksonia sellowiana, Ericaceae: Pernettya prostrata, Gaultheria, Schinus, Vaccinium, Lauraceae: Nectandra cuneatocordata, Poaceae: Bambusa, Chusquea, Guadua, Palmaceae: Ceroxylon, Rosaceae: Rubus, Hesperomeles ferruginea, H. lanuginosa, Prunus brittianus, Symplocaceae: Symplocos cernua |
| Invertebrates: | Annelida, Coleoptera, Dermaptera, Diptera, Hymenoptera, Isoptera, Orthoptera |
| Mammals: | Artiodactyla, Carnivora, Cingulata, Lagomorpha, Perissodactyla, Pilosa, Rodentia |
References: [4, 6, 7, 8, 17, 113, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130]
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 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
IUCN Redlist: https://www.iucnredlist.org/species/22066/123792952
Spectacled Bear Conservation: https://sbc-peru.org/
Chester Zoo: https://www.chesterzoo.org/animals/andean-bear
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