Tremarctos
| Tremarctos Temporal range: Pliocene - Recent,
| |
|---|---|
| |
| Spectacled bear, Tremarctos ornatus | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Family: | Ursidae |
| Subfamily: | Tremarctinae |
| Genus: | Tremarctos Gervais, 1855 |
| Type species | |
| Tremarctos ornatus Cuvier, 1825
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| Species | |
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†Tremarctos floridanus (Gildey, 1928) | |
Tremarctos is a genus of the bear subfamily Tremarctinae, endemic to Americas from the Pliocene to recent. The northern species, the Florida short-faced bear, became extinct 11,000 years ago.[1] The sole living Tremarctos species is the South American spectacled bear.
Species
[edit]- †Tremarctos floridanus - Florida short-faced bear
- Tremarctos ornatus - spectacled bear
Habitat
[edit]Tremarctos floridanus bears lived in the southern parts of North America. Tremarctos ornatus however lives in South America,[2] such as in the Andes Mountains of Peru.[3]They also live in countries like Bolivia and Venezuala.[4] Tremarctos orantus is the only species of bear to live in South America. They like to build nests that they use to sleep and eat in, in trees of high elevation in humid tropical rain forests.[5] They are able to live in other types of biomes too such as temperate grasslands, deciduous forests, and more. Where they choose to live is dependent upon the type of food available in the habitat.[3]
Diet
[edit]The diet of Tremarctos bears contains a lot of variety. They are considered omnivores as they eat foods like fruit, corn, plants, insects, farm animals, and more.[5]
Species under this genus are able to use their paws to manipulate food. They can strip leaves off of trees, pick apart fruits, grasp food, etc. They do this with the help of having a radius sesamoid, also referred to as a "false thumb".[6]
Hunting and eating take up most of a Tremarctos bears activity levels. Tremarctos bears are diturnal meaning that they'll go out during either the day, evening, or night to hunt for food. They do not hibernate. It mostly depends on where the bear is located and what the current season is that determines when they're the most active.[4]
Etymology
[edit]The genus name Tremarctos was created in 1855 by Alfred Gervais.[6] While his suggestion for making Tremarctos a separate genus was rejected, after further studies comparing skeletal structures of the teeth and jaws of Tremarctos to other bear species his suggestion was later then accepted.[3]
The word Tremarctos is derived from the Greek language and translates to "hole bear" in English. If one were to look at humerus of this type of bear, one would notice a hole in the middle of it. This is where its name comes from and why it is called the "hole bear".[7]
Physical Characteristics
[edit]Size
[edit]Species under the Tremartos genus are about average sized bears, similar in size to the American Black Bear. They can weigh anywhere from 150-400 lbs. The Tremarctos Floridanus however, was bigger than Tremarctos Orantus. Both species are sexually dimorphic, meaning the males are most times larger than the females in size. This also results in the males having protein blood levels higher than the females levels.[4] The forelimbs of Tremartos bears are longer than their hindlimbs.
Morphology
[edit]They have long curved claws and have plantigrade feet.[3] As for their fur, they're usually black with a tannish marking that extends from their chest to around their face. While we don't know what Tremarctos Floridanus looked like exactly, it's safe to assume they looked similar to the Tremarctos Ornatus. While they have large and deep skulls, they're actually the smallest in length when comparing their skull to the skulls of other bear species.[4]
Dentation
[edit]The species under the Tremarctos genus have short mandibles as well as short crania. Even though they are omnivores, the evidence of having short mandibles and crania indicates they feed mostly on plants and fruits and only sometimes eat meat. Because of this they also have resilient teeth near their cheeks. They also have small canines and large molars showing they eat meat as well.[8] In total they have 42 teeth.
Breeding
[edit]Courtship occurs between male and female Tremarctos bears and this usually involves vocalizations or playful fighting. Tremarctos are polygamous meaning the male bears breed with multiple different female bears. They are also polyesterous which means the bears have specific breeding seasons. The most common litter inlcudes twin cubs, which are usually given birth to right before fruits and vegetables start growing and becoming ripe.[4]
The mothering bears create dens to take care of their cubs in. They will care for the cubs for about 3 years and after that they will separate.[4] Male Tremarctos bears tend to live longer than the females bears.[3]
References
[edit]- ^ B. Kurten & E. Anderson (1980): Pleistocene mammals of North America, pp 1-442. Columbia University Press
- ^ Trevisan, A; RIbeiro, A.M. (2023). Quaternary International. Vol. 668. pp. 14–26.
- ^ a b c d e Rangel, G (2012). Mammal Review (PDF). Vol. 61 (4th ed.). Mammal Society. pp. 85–119.
- ^ a b c d e f Velez-Liendo, X.; Jackson, D; Ruiz-García, M. (2020). Bears of the World. pp. 78–88.
- ^ a b Peyton, Bernard (1980). Journal of Mammalogy. Vol. 61. pp. 639–652.
- ^ a b Salesa, M.J.; Siliceo, G.; Anton, M.; Abella, J.; Montoya, P.; Morales, J. (2006). Estudios Geológicos.
- ^ Vela-Vargas, Mauricio; Koprowski, J; González-Maya, J; Jorgenson, J (2021). Mammalian Species. Vol. 53. pp. 78–94.
- ^ Figueirido, B.; Soibelzon, L.H. (2009). Inferring palaeoecology in extinct tremarctine bears (Carnivora, Ursidae) using geometric morphometrics.
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