Arctodus

A. simus. Credit: Dantheman9758.

*Arctodus*, the short-faced bears, is an extinct genus of large bear that lived in North America from th Middle Pleistocene to the Early Holocene.

## Description

*A. simus* was common during the North American fauna of its time. *A. pristinus* (ironically known as the "giant short-face bear") was smaller than *A. simus*. They were part of the 'greater megafauna'. A. simus is from the La Brea tar pits, being on of the largest terrestrial carnivores during this time. It went extinct during the ice age.

## Paleobiology

          It is often portrayed as a solitary animal, but its lifestyle is still much under debate. It was likely close to modern omnivorous bears. Scaling of the snout finds that it's snout was not comparatively short, regardless of the common name. Femoral shaft comparisons show that it was also not as long-legged as commonly depicted. Contemporary populations of *Ursus arctos* consumed less flesh than *Arctodus*. Some studies find that it was a massive omnivorous species that varied in diet when resource availability shifted, with others finding a higher concentration of nitrogen-15 in its bones, meaning it was highly carnivorous and required 16kg/day of flesh to survive. Nonetheless, it was probably an omnivore with a varied diet across range, size and maybe species, with skull morphology matching omnivorous bears. It is debated if the old view of *Arctodus* as an apex predator and kleptoparasite are contested based on new study and the idea that it may have been too fragile to attempt such brute force attacks.

## References

* https://bear.org/bear-facts/extinct-short-faced-bear/
* https://www.thoughtco.com/giant-short-faced-bear-arctodus-simus-1093085
* https://bear.org/the-giant-short-faced-bear/
* https://nature.ca/notebooks/english/shrtbear.htm
* https://beringia.com/exhibit/ice-age-animals/giant-short-faced-bear
* https://mnh.uiowa.edu/giant-short-faced-bear
* https://www.nationalgeographic.com/animals/article/110203-biggest-bear-largest-giant-short-faced-animals-science [Famous Specimens portrayed by National Geographic]
* https://ielc.libguides.com/sdzg/factsheets/extinctshort-facedbear/characteristics
* https://www.inaturalist.org/taxa/631982-Arctodus
* https://www.jstor.org/stable/20627694
* https://www.jstor.org/stable/4523425
* https://www.ou.edu/cas/news-updates/2020/Giant-Short-Faced-Bear
* https://www.researchgate.net/publication/249023684\_Demythologizing\_Arctodus\_simus\_the\_%27Short-Faced%27\_Long-Legged\_and\_Predaceous\_Bear\_that\_Never\_Was [a more critical study]
* https://www.tandfonline.com/doi/pdf/10.1080/02724630903416027 [a more critical study]
* https://www.academia.edu/751564 [The study that points toward more Carnivorous diet]
* https://royalsocietypublishing.org/doi/10.1098/rsbl.2016.0062 [Convergent Evolution case study]
* https://www.sciencedirect.com/science/article/abs/pii/S0016699517300384
* https://cdnsciencepub.com/doi/10.1139/E10-018
* https://www.researchgate.net/publication/250071137\_Giant\_Short-faced\_Bears\_Arctodus\_simus\_in\_Pleistocene\_Florida\_USA\_a\_Substantial\_Range\_Extension
* http://www.adfg.alaska.gov/index.cfm?adfg=wildlifenews.view\_article&articles\_id=232