''Ursus rossicus'' (the Pleistocene small

cave bear The cave bear (''Ursus spelaeus'') is a prehistoric species of bear that lived in Europe and Asia during the Pleistocene and became extinct about 24,000 years ago during the Last Glacial Maximum. Both the word "cave" and the scientific name ' ...

) is an extinct species of bear that lived in the steppe regions of northern Eurasia and Siberia during the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...

Discovery

Vereshchagin discovered the first ''U. rossicus'' remains in the Altai Mountains in 1973. Mandibles of the bear were found in Bachatsk Quarry, Krasni Yar (in Tomsk Province) and Mokhovo Quarry; skull fragments were found in Krasni Yar.

Description

The small cave bear had a very broad, domed skull with a steep forehead. Its stout body had long thighs, massive shins and in-turning feet, making it similar in skeletal structure to the brown bear. Cave bears were comparable in size to the largest modern-day bears.

Diet

Cave bear teeth show greater wear than most modern bear species, suggesting a diet of tough materials. However,

tubers Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing s ...

and other gritty food, which cause distinctive tooth wear in modern brown bears, do not appear to have constituted a major part of cave bears' diets on the basis of

dental microwear Dental microwear analysis is a method to infer diet and behavior in extinct animals, especially in fossil specimens. Typically, the patterns of pits and scratches on the occlusal or buccal surface of the enamel are compared with patterns observed ...

analysis. The morphological features of the cave bear chewing apparatus, including loss of premolars, have long been suggested to indicate their diets displayed a higher degree of

herbivory A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

than the

Eurasian brown bear The Eurasian brown bear (''Ursus arctos arctos'') is one of the most common subspecies of the brown bear, and is found in much of Eurasia. It is also called the European brown bear, common brown bear, common bear, and colloquially by many othe ...

. Indeed, a solely vegetarian diet has been inferred on the basis of tooth morphology. Results obtained on the stable isotopes of cave bear bones also point to a largely vegetarian diet in having low levels of

nitrogen-15 Natural nitrogen (7N) consists of two stable isotopes: the vast majority (99.6%) of naturally occurring nitrogen is nitrogen-14, with the remainder being nitrogen-15. Fourteen radioisotopes are also known, with atomic masses ranging from 10 to 25, ...

and

carbon-13 Carbon-13 (13C) is a natural, stable isotope of carbon with a nucleus containing six protons and seven neutrons. As one of the environmental isotopes, it makes up about 1.1% of all natural carbon on Earth. Detection by mass spectrometry A mas ...

, which are accumulated at a faster rate by carnivores as opposed to herbivores. Cave bears of the last ice age lacked the usual two or three premolars present in other bears; to compensate, the last molar is very elongated, with supplementary cusps.Gli orsi spelèi delle Conturines/ Ursus Spelaeus
Altabadia.it. Retrieved on 2011-09-26.

References

Pleistocene bears Prehistoric mammals of Europe Pleistocene carnivorans Fossil taxa described in 1930 {{paleo-carnivora-stub