Testosterone concentrations in juvenile male polar bears (Ursus maritimus)
The ex situ polar bear population in the United States is not sustainable. Current management practices include pairing mates at five to six years of age, but there is evidence that wild bears have sired cubs as early as two years old. Timing acquisition of sexual maturity in male polar bears could...
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Elsevier
2024-01-01
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| Series: | Theriogenology Wild |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2773093X24000357 |
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| author | Jessye Wojtusik Megan Philpott Elizabeth Donelan Monica A. Stoops Terri L. Roth Erin Curry |
| author_facet | Jessye Wojtusik Megan Philpott Elizabeth Donelan Monica A. Stoops Terri L. Roth Erin Curry |
| author_sort | Jessye Wojtusik |
| collection | DOAJ |
| description | The ex situ polar bear population in the United States is not sustainable. Current management practices include pairing mates at five to six years of age, but there is evidence that wild bears have sired cubs as early as two years old. Timing acquisition of sexual maturity in male polar bears could aid in determining when mates should be paired in ex situ populations. To address this, non-invasive fecal testosterone metabolite monitoring was evaluated as a technique for establishing age of sexual maturity in 14 male polar bears (aged 1–6.9 years) for 1–6 years. Testosterone metabolite concentrations were monitored throughout the year and evaluated by breeding season (Jan. 1 – May 21) compared to non-breeding season (May 22 – Dec. 31). Sexual maturity was defined as when testosterone metabolite concentrations were significantly greater during breeding season than non-breeding season and bi-weekly averages were elevated above baseline for a minimum of ten weeks during breeding season mimicking patterns in adult male polar bears. Testosterone metabolite concentrations ranged from 5.9 to 8342 ng/g. One bear met the defined criteria at two years of age and an additional three bears met criteria at three years old. Due to the sampling strategy and the requirements set forth by the definition of sexual maturity, there were confounding results. In two cases, bears determined to be sexually mature the year prior, were not categorized as mature the next year. Another bear demonstrated greater testosterone metabolite values during the non-breeding season than breeding season. This study demonstrated the variability in fecal testosterone metabolites in juvenile polar bears and results suggest that hormone assessment alone is not adequate for determining sexual maturity in ex situ male polar bears. However, if used in tandem with behavioral monitoring and semen collection, when possible, could aid breeding management decisions for ex situ populations. |
| format | Article |
| id | doaj-art-84e24b4240ba4e09b21006113181ffb3 |
| institution | DOAJ |
| issn | 2773-093X |
| language | English |
| publishDate | 2024-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Theriogenology Wild |
| spelling | doaj-art-84e24b4240ba4e09b21006113181ffb32025-08-20T02:50:27ZengElsevierTheriogenology Wild2773-093X2024-01-01510010410.1016/j.therwi.2024.100104Testosterone concentrations in juvenile male polar bears (Ursus maritimus)Jessye Wojtusik0Megan Philpott1Elizabeth Donelan2Monica A. Stoops3Terri L. Roth4Erin Curry5Center for Conservation and Research of Endangered Wildlife, Cincinnati Zoo & Botanical Garden, Cincinnati, OH 45220, USACenter for Conservation and Research of Endangered Wildlife, Cincinnati Zoo & Botanical Garden, Cincinnati, OH 45220, USACenter for Conservation and Research of Endangered Wildlife, Cincinnati Zoo & Botanical Garden, Cincinnati, OH 45220, USACenter for Conservation and Research of Endangered Wildlife, Cincinnati Zoo & Botanical Garden, Cincinnati, OH 45220, USACenter for Conservation and Research of Endangered Wildlife, Cincinnati Zoo & Botanical Garden, Cincinnati, OH 45220, USACorresponding author.; Center for Conservation and Research of Endangered Wildlife, Cincinnati Zoo & Botanical Garden, Cincinnati, OH 45220, USAThe ex situ polar bear population in the United States is not sustainable. Current management practices include pairing mates at five to six years of age, but there is evidence that wild bears have sired cubs as early as two years old. Timing acquisition of sexual maturity in male polar bears could aid in determining when mates should be paired in ex situ populations. To address this, non-invasive fecal testosterone metabolite monitoring was evaluated as a technique for establishing age of sexual maturity in 14 male polar bears (aged 1–6.9 years) for 1–6 years. Testosterone metabolite concentrations were monitored throughout the year and evaluated by breeding season (Jan. 1 – May 21) compared to non-breeding season (May 22 – Dec. 31). Sexual maturity was defined as when testosterone metabolite concentrations were significantly greater during breeding season than non-breeding season and bi-weekly averages were elevated above baseline for a minimum of ten weeks during breeding season mimicking patterns in adult male polar bears. Testosterone metabolite concentrations ranged from 5.9 to 8342 ng/g. One bear met the defined criteria at two years of age and an additional three bears met criteria at three years old. Due to the sampling strategy and the requirements set forth by the definition of sexual maturity, there were confounding results. In two cases, bears determined to be sexually mature the year prior, were not categorized as mature the next year. Another bear demonstrated greater testosterone metabolite values during the non-breeding season than breeding season. This study demonstrated the variability in fecal testosterone metabolites in juvenile polar bears and results suggest that hormone assessment alone is not adequate for determining sexual maturity in ex situ male polar bears. However, if used in tandem with behavioral monitoring and semen collection, when possible, could aid breeding management decisions for ex situ populations.http://www.sciencedirect.com/science/article/pii/S2773093X24000357Enzyme immunoassayNon-invasive hormone monitoringPolar bearSexual maturityTestosterone metabolitesThreatened species |
| spellingShingle | Jessye Wojtusik Megan Philpott Elizabeth Donelan Monica A. Stoops Terri L. Roth Erin Curry Testosterone concentrations in juvenile male polar bears (Ursus maritimus) Theriogenology Wild Enzyme immunoassay Non-invasive hormone monitoring Polar bear Sexual maturity Testosterone metabolites Threatened species |
| title | Testosterone concentrations in juvenile male polar bears (Ursus maritimus) |
| title_full | Testosterone concentrations in juvenile male polar bears (Ursus maritimus) |
| title_fullStr | Testosterone concentrations in juvenile male polar bears (Ursus maritimus) |
| title_full_unstemmed | Testosterone concentrations in juvenile male polar bears (Ursus maritimus) |
| title_short | Testosterone concentrations in juvenile male polar bears (Ursus maritimus) |
| title_sort | testosterone concentrations in juvenile male polar bears ursus maritimus |
| topic | Enzyme immunoassay Non-invasive hormone monitoring Polar bear Sexual maturity Testosterone metabolites Threatened species |
| url | http://www.sciencedirect.com/science/article/pii/S2773093X24000357 |
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