New Data on Large Brown Bear (Ursus arctos L., 1758, Ursidae, Carnivora, Mammalia) from the Pleistocene in Yakutia

Abstract

New finds of brown bear (Ursus arctos L., 1758) fossil remains from the territory of Yakutia, namely, skulls and mandibular bones, have been investigated. The new finds are exceptionally large: most dimensions of these specimens exceed those of the present-day brown bears of Yakutia and even the maximal parameters of the largest individuals of the present-day Eurasian subspecies U. a. beringianus and U. a. piscator. Analysis of various data showed that giant brown bears had inhabited northern Yakutia during the Karginian interstadial in the Late Pleistocene.

Palaeoecological and genetic analyses of Late Pleistocene bears in Asiatic Russia

“…Late Pleistocene steppe brown bears were distributed from western Europe to NE Asia, inhabiting open environments. Although this general Pleistocene range matches that of the modern northern Asiatic brown bear, the steppe brown bears were characteristically larger and differed markedly from their modern descendants by having larger skulls and large and unusually broad molars (Baryshnikov & Boeskorov 2004;Boeskorov et al 2019;Marciszak et al 2019). The minimum sizes recorded of the humerus bones of modern bears are also much smaller than the minimum S3), according to their region of origin.…”

“…Although this general Pleistocene range matches that of the modern northern Asiatic brown bear, the steppe brown bears were characteristically larger and differed markedly from their modern descendants by having larger skulls and large and unusually broad molars (Baryshnikov & Boeskorov 2004; Boeskorov et al . 2019; Marciszak et al . 2019).…”

“…At the beginning of the Late Pleistocene, the smaller Ursus arctos priscus occupied this area, and at the end of the Pleistocene and in the Holocene an even smaller U. arctos, similar in size to the modern Yakutian brown bear, was present (Boeskorov & Baryshnikov 2013). There is now abundant evidence that the Late Pleistocene large brown bear form, U. a. priscus, was widespread not only in Yakutia but also in Chukotka, western Siberia and the Urals, as well as in eastern and western Europe (Vereshchagin 1973;Alekseeva 1980;Baryshnikov 2007;Doppes & Pacher 2014;Kosintsev & Bachura 2015;Marciszak et al 2015Marciszak et al , 2019Boeskorov et al 2019). Presumably, the large size of Late Pleistocene bears in Yakutia was caused by an increase in the amount of available food (Boeskorov et al 2019).…”

“…There is now abundant evidence that the Late Pleistocene large brown bear form, U. a. priscus, was widespread not only in Yakutia but also in Chukotka, western Siberia and the Urals, as well as in eastern and western Europe (Vereshchagin 1973;Alekseeva 1980;Baryshnikov 2007;Doppes & Pacher 2014;Kosintsev & Bachura 2015;Marciszak et al 2015Marciszak et al , 2019Boeskorov et al 2019). Presumably, the large size of Late Pleistocene bears in Yakutia was caused by an increase in the amount of available food (Boeskorov et al 2019). However, except for a recent comparison of stable isotopes of Pleistocene and modern Yakutian brown bears (Krylovich et al 2020), a systematic comparison of the diets of fossil brown bears from different regions of Russia has not yet been carried out.…”

“…In recent years, exceptionally large subfossil Pleistocene specimens of brown bear have been discovered in the territory of Yakutia, raising questions concerning the taxonomic, ecological, trophic and genetic positions of these large, ice age brown bears in NE Siberia (Boeskorov et al 2019;Marciszak et al 2019;Rey-Iglesia et al 2019;Krylovich et al 2020). However, the identification of bear bones, especially humeri, is often difficult because only Asian black bear (Ursus thibetanus), which constantly uses its forelimbs for climbing trees, has a humerus that differs markedly from that of other bear species (Gromova 1950;Meloro & de Oliveira 2019).…”