We are pleased to share these recent URSUS articles with you. The articles below can be accessed through your IBA membership account link to BioOne.
Temporal segregation between female Asiatic black bears with unweaned offspring and solitary bears
Shota Umano, Tomoki Mori, Kazuteru Mikuni, Yasuaki Niizuma
Ursus 2024 (35e14), 1-8, (2 September 2024) https://doi.org/10.2192/URSUS-D-23-00023.1
KEYWORDS: Asiatic black bears, behavior, Camera trap, competition, infanticide, Japan, temporal segregation, Ursus thibetanus
Mammalian females with unweaned offspring often engage in spatial and temporal segregation to avoid encounters with conspecifics, reducing the risks of infanticide and resource competition. Such behavioral strategies have been reported in bears (Ursus spp.), but knowledge is limited in Asiatic black bears (U. thibetanus). Here, we investigated the temporal segregation of Asiatic black bears with unweaned offspring as a behavioral strategy, using 21 camera traps in Shirakawa Village, Gifu Prefecture, Japan, from June to October 2019. Such a behavioral strategy would be influenced by food abundance, so we also evaluated the production of 6 fruits that are consumed by bears in the study area. Although a direct relationship may not be evident, our findings provided preliminary but suggestive evidence of temporal segregation, with females with unweaned offspring displaying increased daytime activity compared with solitary bears, possibly as an attempt to avoid infanticide and competition for food access.
A case of hyperdontia in grizzly bear in British Columbia
Tyler J. Brasington
Ursus 2024 (35e15), 1-5, (2 September 2024) https://doi.org/10.2192/URSUS-D-23-00018R1
KEYWORDS: British Columbia, dentition, grizzly bears, hyperdontia, oral pathology, supernumerary dentition, teeth, Ursus arctos
Hyperdontia refers to an excess number of teeth past the expected number of teeth for an individual located in the mandible or maxilla. These extra teeth are often referred to as “supernumerary.” This condition is a relatively uncommon, infrequent phenomenon scarcely documented in Ursidae globally, with only a handful of examples documented in literature. In 2008, an indigenous hunter harvested a grizzly bear (Ursus arctos) in Smithers, British Columbia, Canada. The bear exhibited 7 maxillary incisors, with a supernumerary tooth present. This observation serves as the first-ever record of the supernumerary dentition of the incisors in brown bears.