title: Incidence of ovulation without coital stimuli in captive Japanese black bears (Ursus thibetanus japonicus) based on serum progesterone profiles.
abstract: The purpose of this study was to ascertain whether or not Japanese black bears (Ursus thibetanus japonicus) are induced ovulators. The progesterone levels of female bears kept with a male and allowed to mate (n=2) and female bears allowed contact with a male through bars but not allowed to mate (n=6) during the mating season increased significantly in late October. Based on this result, the female bears were considered to have ovulated. Females isolated from males (n=3) were ovarioectomized after the mating season, and no corpora lutea were observed, indicating they had not ovulated. These findings suggest that Japanese black bears may be induced ovulators that ovulate with stimuli from males and without coitus at a high rate.
authors.affiliation: United Graduate School of Veterinary Sciences, Gifu University, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Okano
authors.forename: Sachiko
authors.initials: S
authors.lastname: Nakamura
authors.forename: Rumiko
authors.initials: R
authors.lastname: Nakashita
authors.forename: Takeshi
authors.initials: T
authors.lastname: Komatsu
authors.forename: Tetsuma
authors.initials: T
authors.lastname: Murase
authors.forename: Makoto
authors.initials: M
authors.lastname: Asano
authors.forename: Toshio
authors.initials: T
authors.lastname: Tsubota
mesh_terms: D000818:Animals; D000836:Animals, Zoo; D004958:Estradiol / Q000097:blood; D005260:Female; D008297:Male; D010060:Ovulation / Q000502:physiology*; D011374:Progesterone / Q000097:blood*; D001503:Ursidae / Q000097:blood / Q000502:physiology*
chemical_list: D011374:Progesterone; D004958:Estradiol