Environment influences morphology and development for in situ and ex situ populations of the black-footed ferret (Mustela nigripes)

Abstract

For selected species, conservation breeding has become integrated into recovery plans, most often through the production of offspring for reintroduction into nature. As these programs increase in size and scope, it is imperative that conservation managers retain the biological integrity of the species. This study investigated the causes of morphological changes that are known to occur in black-footed ferrets (Mustela nigripes) maintained ex situ. In a previous study, ferrets maintained in captivity were 5-10% smaller in body size than pre-captive, in situ animals. In the present study, the authors compared nine morphological characters among ex situ animals and their in situ descendants. Within the ex situ population, cage types were compared to determine whether housing influenced morphometry. Black-footed ferrets born to reintroduced individuals quickly returned to their pre-captive size suggesting that a diminutive morphology ex situ did not have a genetic basis. Furthermore, cage type affected overall body size and shape; ulnas and tibias were as much as 9% shorter for ex situ animals. The authors hypothesise that small cage size and environmental homogeneity inhibit the mechanical stimuli necessary for long bone development. These findings have ramifications for ex situ managers who need to create artificial captive settings that promote natural physical development. In the absence of such an environment, 'unnatural' morphologies can result that may contribute to poor fitness or perhaps even domestication.

Phenotypic variation of an alien species in a new environment: the body size and diet of American mink over time and at local and continental scales

“…In the WMNP and in Belarus, a decrease in the body size of mink occurred during the first 7–10 years after invasion. Similarly, in the black‐footed ferret Mustela nigripes , wild‐born members of a reintroduced population returned to precaptive body size in 3 years (1–2 generations) (Wisely et al ., 2005). Considering the relatively short time periods involved, these results may suggest that phenotypic changes in response to environmental factors may be primarily dictated by individual plasticity in trait expression rather than strictly heritable quantitative genetic variation.…”

Genotypic and phenotypic consequences of reintroduction history in the black-footed ferret (Mustela nigripes)

“…Many morphological studies (e.g., Fleischer and Murphy 1992;Komers and Komers 1992), including two for this species (Wisely et al 2002(Wisely et al , 2005, inferred the first principal component (PC1) to represent overall body size. We analyzed factor components from the PC1 with an ANOVA with sex and location as fixed factors and a = 0.05.…”

“…We tested a posteriori for pairwise differences among populations in body size with Tukey's HSD test. Because black-footed ferrets are known to be sexually dimorphic (Anderson et al 1986;Wisely et al 2005) we did not report results for differences among sexes.…”

Testing an ecophysiological mechanism of morphological plasticity in pupfish and its relevance to conservation efforts for endangered Devils Hole pupfish

“…For instance, black-footed ferrets (Mustela nigripes) bred and raised in captivity have shorter-length bones in the forearms and rear legs, and these changes appear to result from plastic responses to rearing conditions (Wisely et al, 2005). Indeed many animals reared in captivity show behavioral changes that impede the success of reintroduction and supplementation programs (Snyder et al, 1996;Wallace, 2000).…”