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Fort Collins, CO, United States

Fanson K.V.,Macquarie University | Fanson K.V.,Purdue University | Wielebnowski N.C.,Chicago Zoological Society | Shenk T.M.,Mammals Research | And 3 more authors.
General and Comparative Endocrinology | Year: 2010

Canada lynx are listed as a threatened species in the contiguous US. Understanding the reproductive characteristics (i.e., mating system, behavior, physiology) of a species is useful for ensuring effective in situ and ex situ management plans. The goal of this study was to describe patterns of androgen expression in both captive and wild male Canada lynx using fecal hormone metabolite analysis. Among captive lynx, juvenile and castrated males had lower concentrations of fecal androgens (fA) than intact males, thereby demonstrating that the assay detects biologically meaningful differences in testicular activity. We found that captive males in general had much higher fA levels than wild males. All males showed strong seasonal variation in fA concentrations, with significantly higher levels being expressed during the breeding season (February and March) than during the non-breeding season. Among captive males, variation in seasonal fA levels did not correlate with latitude. Finally, males housed with intact cage-mates (either male or female) had significantly higher fA levels than males housed alone or with a neutered cage-mate. © 2010 Elsevier Inc. Source


Fanson K.V.,Macquarie University | Fanson K.V.,Purdue University | Wielebnowski N.C.,Chicago Zoological Society | Shenk T.M.,Mammals Research | And 3 more authors.
General and Comparative Endocrinology | Year: 2010

Canada lynx face some unique breeding restrictions, which may have implications for population viability and captive management. The goal of this study was to improve our understanding of basic reproductive physiology in Canada lynx. Using fecal hormone metabolite analysis, we established normative patterns of fecal estrogen (fE) and progestagen (fP) expression in captive and wild female Canada lynx. Our results indicate that Canada lynx have persistent corpora lutea, which underlie their uncharacteristic fP profiles compared to other felids. Thus, fP are not useful for diagnosing pregnancy in Canada lynx. We also found that Canada lynx are capable of ovulating spontaneously. Captive females had higher concentrations of fE and fP than wild females. Both populations exhibit a seasonal increase in ovarian activity (as measured by fE) between February and April. Finally, there was evidence of ovarian suppression when females were housed together. © 2010 Elsevier Inc. Source


Bergman E.J.,Mammals Research | Doherty P.F.,Colorado State University | Bishop C.J.,Mammals Research | Wolfe L.L.,Mammals Research | Banulis B.A.,Terrestrial Programs
PLoS ONE | Year: 2014

The relationships between habitat, body condition, life history characteristics, and fitness components of ungulates are interwoven and of interest to researchers as they strive to understand the impacts of a changing environment. With the increased availability of portable ultrasound machines and the refinement of hormonal assays, assessment of ungulate body condition has become an accessible monitoring strategy. We employed body condition scoring, estimation of % ingestafree body fat (%IFBF), assessment of free thyroid hormones (FT4 and FT3), and assessment of pregnancy, as metrics to determine if landscape-level habitat treatments affected body condition of adult (≥1.5 years old) female mule deer (Odocoileus hemionus). All body condition related metrics were measured on 2 neighboring study areas - a reference area that had received no habitat treatments and a treatment study area that had received mechanical removal of pinyon pine (Pinyus edulis) - Utah juniper (Juniperus osteosperma) forest, chemical control of weeds, and reseeding with preferred mule deer browse species. A consistent trend of higher %IFBF was observed in the treatment study area (%¯IFBF=7:38, SD, 1:31) than in the reference study area (%¯IFBF=6:97, SD=2:16), although variation of estimates was larger than hypothesized. A similar pattern was observed with higher thyroid hormones concentrations being observed in the treatment study area, but large amounts of variation within concentration estimates were also observed. The consistent pattern of higher body condition related estimates in our treatment study area provides evidence that large mammalian species are sensitive to landscape change, although variation within estimates underlie the challenge in detecting population level impacts stemming from environmental change. © 2014 Bergman et al. Source

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