Observation of sexual behavior under captive conditions in Hokkaido brown bears (Ursus arctos yesoensis).

Tsubota, Toshio; Kanagawa, Hiroshi; Takahashi, Ken­ichi; Yasue, Ken; Fukunaga, Shigeharu

doi:10.1262/jrd1977.31.203

Cited by 20 publications

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“…1 and Table 1). These changes were in agreement with the previous findings [8][9][10] and suggest that ovulation and the formation of corpora lutea occurred around the end of the estrous period. Serum estradiol-17β levels were higher during the period when copulation was observed (May) than in the post-breeding period (July) in American black bears [8] and a small increase of serum progesterone was observed after copulation in brown [10] and American black bears [8].…”

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confidence: 93%

“…Serum estradiol-17β levels were higher during the period when copulation was observed (May) than in the post-breeding period (July) in American black bears [8] and a small increase of serum progesterone was observed after copulation in brown [10] and American black bears [8]. However, we could not determine which copulations were fertile since copulation with quivering, a sign of ejaculation [9], were observed multiple times [data for quivering not shown]. Further, any common patterns that may indicate the type and the length of the estrous cycle and the exact timing of ovulation were not found in the changes of estradiol-17β and progesterone.…”

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confidence: 73%

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Changes in Sexual Behavior and Fecal Steroid Hormone Concentrations during the Breeding Season in Female Hokkaido Brown Bears (Ursus arctos yesoensis) under Captive Condition.

Ishikawa

Sakamoto²,

Katagiri

et al. 2003

The Journal of Veterinary Medical Science

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ABSTRACT. The longitudinal changes in fecal steroid hormone concentrations and sexual behavior in 2 mated/pregnant and 3 non-mated female Hokkaido brown bears were investigated during the breeding season. Behavioral estrus (standing) lasted for 14 and 32 days in the mated females and for 25 to 36 days in the non-mated females. In non-mated females, sexual behavior, such as female-female mounting and masturbation, was observed for several days before and after the estrous period. In mated females, mean fecal estradiol-17β concentrations were higher in the estrous period than in the post-estrous period, while fecal progesterone concentrations were higher in the post-estrous period than in the estrous period. The similar trends of steroid hormone changes were observed in the non-mated females.

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confidence: 73%

Changes in Sexual Behavior and Fecal Steroid Hormone Concentrations during the Breeding Season in Female Hokkaido Brown Bears (Ursus arctos yesoensis) under Captive Condition.

Ishikawa

Sakamoto²,

Katagiri

et al. 2003

The Journal of Veterinary Medical Science

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“…The mating season of the Hokkaido brown bear usually extends from early May to early July in captive conditions [10]. From macroscopic and histological observations of the testes of this bear, Tsubota and Kanagawa [11] reported that active spermatogenesis is sustained from February to September.…”

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confidence: 99%

Electroejaculation and Semen Characteristics of the Captive Hokkaido Brown Bear. (Ursus arctos yesoensis)

Ishikawa

Matsui

Tsuruga

et al. 1998

The Journal of Veterinary Medical Science

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ABSTRACT. An electroejaculation technique was applied to the Hokkaido brown bear (Ursus arctos yesoensis) for semen collection and characterization of their seminal traits. Ten captive sexually mature bears were anesthetized and subjected to 21 electroejaculation trials during their mating season in 1995 and 1996. Spermic electroejaculates were recovered from 6 of the 10 bears (14 of 21 trials). The semen was characterized by serous fluid of semitransparent white color and a neutral pH. The mean values of ejaculate volume, sperm concentration, percentage of sperm motility, percentage of live spermatozoa, and percentage of pleiomorphic forms were 2.7 ml, 471.6 × 10 6 cells/ml, 80.2%, 89.7% and 21.8%, respectively. Although there was considerable variation among the seminal traits of the individual bears, the electroejaculation technique was effective in obtaining ejaculates from captive bears. -KEY WORDS: brown bear, electroejaculation, seminal trait.J. Vet. Med. Sci. 60(8): 965-968, 1998 domestic animal diets and some vegetables were provided, and the bears were housed in indoor/outdoor enclosures under the natural light cycle. All males were separated from females by a grid wall, but had visual, aural, and/or olfactory contacts during the experimental periods. A surgical plane of anesthesia was induced with an intramuscular (i.m.) injection of tiletamine HCl-zolazepam (Zoletil; 100 mg/ml, Virbac, Carros, France) at a dose of 3 mg/kg body weight by pole syringe in 19 trials. For male D (Trial no. 11), 0.01 mg/kg atropine sulfate (Atropine sulfate injection, Tanabe, Osaka, Japan) was given before the injection of tiletamine HCl-zolazepam. Male A (Trial no. 5) was preanesthetized by an i.m. injection of 0.25 mg/kg midazolam (Dormicum, Roche, Basel, Switzerland) and immobilized by an i.m. injection of 5.0 mg/kg ketamine HCl (Ketalar, Sankyo, Tokyo, Japan). With the anesthetic plane with midazolam and ketamine HCl, the animal was less immobilized than in the other trials.

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“…pre-breeding (February), transitional (April), breeding (May and June; Tsubota et al 1985;Ishikawa et al 2003), and post-breeding (August and October), which is classified on the basis of the previous study about testosterone of male brown bears (Tsubota and Kanagawa 1989). To examine whether or not sebaceous gland enlargement is specific to skin on the back during the breeding season, we compared skin sampled from back and rump, because back rubbing is a core posture, whereas rump rubbing is not (Clapham et al 2014).…”

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confidence: 99%

“…Because the mating system of brown bears is polygynous, adult males fight with each other for opportunities to mate with females during the breeding season (May-July; Tsubota et al 1985;Ishikawa et al 2003). Young male bears disperse from their natal areas, probably to avoid mating competition with older bears (Zedrosser et al 2007), and they are likely able to identify sexually mature male brown bears by odors emitted from anal sacs (Rosell et al 2011;Jojola et al 2012).…”

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Testosterone-related and seasonal changes in sebaceous glands in the back skin of adult male brown bears (Ursusarctos)

et al. 2018

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Keyword:brown bear, sebaceous gland, testosterone, tree rubbing, back skin, scent gland, Ursus arctos https://mc06.manuscriptcentral.com/cjz-pubs AbstractAdult male brown bears (Ursus arctos; Linnaeus, 1758) display tree-marking behavior to chemically signalize the dominance throughout the non-denning period, and this behavior peaks during breeding season. Within the scent-marking sequence, back rub is one of a core marking postures. The present study investigated 1) seasonal changes in sebaceous glands in the back skin of brown bears and 2) the relationship between those changes and testosterone levels. Back skin tissue samples and blood were collected from captive adult intact and castrated males during pre-breeding, transitional, breeding and post-breeding seasons, which were concurrent with back skin observations. In intact males, during the transitional and breeding seasons, an oily secretion from the back skin was observed along with enlarged sebaceous glands. The plasma testosterone concentrations during the transitional and breeding seasons were increased compared with the pre-and post-breeding seasons. Secretions and enlarged sebaceous glands were not found in castrated males, and the plasma testosterone concentrations remained at baseline levels. Oily secretions of the back skin glands that appear more abundant during breeding season are rubbed against trees. Changes in size and volume of sebaceous glands, and thus their secreting capacity, are likely testosterone-regulated.

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Observation of sexual behavior under captive conditions in Hokkaido brown bears (Ursus arctos yesoensis).

Cited by 20 publications

References 0 publications

Changes in Sexual Behavior and Fecal Steroid Hormone Concentrations during the Breeding Season in Female Hokkaido Brown Bears (Ursus arctos yesoensis) under Captive Condition.

Changes in Sexual Behavior and Fecal Steroid Hormone Concentrations during the Breeding Season in Female Hokkaido Brown Bears (Ursus arctos yesoensis) under Captive Condition.

Electroejaculation and Semen Characteristics of the Captive Hokkaido Brown Bear. (Ursus arctos yesoensis)

Testosterone-related and seasonal changes in sebaceous glands in the back skin of adult male brown bears (Ursusarctos)

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