• Version
• Download 9
• File Size 222.12 KB
• Create Date 1 January 1990
• Download

The ovaries and uteri of 25 wild adult female Hokkaido brown bears (Ursus arctos yesoensis), killed by hunters during the March-May period from 1982 to 1986 in Hokkaido, Japan, were observed macroscopically and histologically for the presence of corpora albicantia (CA) and placental scars (PS). The numbers of CA, PS and young were compared. The female bears were classified into 4 groups: solitary females, females accompanied by their cubs, yearlings, or 2-year-old young. CA were classified into 3 types (I, II or III) based on the degree of degeneration. Of the 3 types, only Type I CA were regarded as formed recently. PS were classified into 2 types (new or old) according to size. The relationship among numbers of Type I CA, PS and young was examined for each group of females. Type I CA and new PS were observed in some solitary females. These findings may mean the occurrence of embryo loss during delayed implantation, abortion after placentation, and/or death of young after birth.