Abstract
Serum hormone levels were compared between captive and free-living maned wolves and seasonal variations of sex hormones were studied. Blood samples were collected from 16 male and 26 female adult animals from Brazilian zoos, and from 30 male and 24 female free-living adults to determine serum progesterone and testosterone by radioimmunoassay. Serum testosterone concentrations varied (P < 0.05) across seasons for 16 captive males, being higher in autumn (2184.7 +/- 355.1 pg/mL) than in summer (1080.7 +/- 205.4 pg/mL), winter (1270.1 +/- 276.6 pg/mL) and spring (963.9 +/- 248.1 pg/mL), although they did not differ between summer, winter and spring. Testosterone concentration of 30 free-living males differed (P < 0.05) between autumn (824.1 +/- 512.2 pg/mL), winter (14.4 +/- 8.0 pg/mL) and spring (151.9 +/- 90.5 pg/mL). Comparison between captive and free-living animals showed no difference in autumn (P > 0.05). Sixteen captive males showed higher testosterone concentration during winter and spring compared with 30 free-living animals (P < 0.05). Progesterone concentration varied among seasons in 26 captive females (P < 0.05), being higher in autumn (15.3 +/- 3.1 ng/mL) than in summer (6.6 +/- 1.5 ng/mL), winter (5.3 +/- 3.1 ng/mL) and spring (4.3 +/- 0.7 ng/mL). Progesterone concentration of 24 free-living females varied between autumn (17.1 +/- 6.0 ng/mL) and winter (1.7 +/- 0.3 ng/mL) (P < 0.05), but we could not obtain data for spring or summer. No difference in progesterone levels was observed between captive and free-living females in autumn and winter.
Highlights
The maned wolf Chrysocyon brachyurus is the largest canid (20-25 kg) and one of the most typical species present in the grassland areas of the Brazilian Central Highlands (1)
The reproductive-endocrine characteristics of South American captive populations are unknown and there is no information on the reproductive endocrine function of freeliving maned wolf populations
Blood samples were collected from 42 captive adult maned wolves (16 males and 26 females) from Brazilian zoos (Parque Natural da Companhia Brasileira de Metalurgia de Mineração, Araxá, MG, N = 8; Fundação Zoobotânica de Belo Horizonte, Belo Horizonte, MG, N = 9; Zoológico Municipal de Curitiba, Curitiba, PR, N = 5; Parque Zoológico Quinzinho de Barros, Sorocaba, SP, N = 6; Zoológico de Brasília, Brasília, DF, N = 4; Fundação Rio-Zôo, Rio de Janeiro, RJ, N = 4; Zoológico Municipal de Guarulhos, Guarulhos, SP, N = 2; Zoológico Municipal de Americana, Americana, SP, N = 4)
Summary
The maned wolf Chrysocyon brachyurus is the largest canid (20-25 kg) and one of the most typical species present in the grassland areas of the Brazilian Central Highlands (1). We observed a difference (P < 0.05) between autumn (824.1 ± 512.2 pg/mL; range: 8.4-3515.9 pg/mL; N = 7), winter (14.4 ± 8.0 pg/mL; range: 0.8-102.9 pg/mL; N = 13) and spring (151.9 ± 90.5 pg/mL; range: 1.4-889.1 pg/ mL; N = 10) for testosterone concentration in free-living male maned wolves (Figure 1). We could not capture and collect samples from free-living male maned wolves during summer.
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