In several species, stress compromises maternal behaviors that are important for infant viability (e.g. licking and grooming). Understanding how stress in captivity affects maternal behavior could therefore be beneficial, especially for carnivores in zoos and breeding centers where infant mortality is often high. We used a model carnivore--American mink--to test two hypotheses, namely that maternal investment and/or behavior is i. improved by environmental enrichment; and ii. compromised by stereotypic behavior. We observed 22 females raised in an indoor facility, 9 enriched, 13 non-enriched. At birth, and at post-natal day 20 when altricial infants were still fully dependent on their mothers, the following offspring variables were recorded: litter size, infant mortality, litter sex ratio (post-natal day 1), and weight. Maternal behavior was assessed by recording nest shape (post-natal day 1), and the frequency of licking and grooming (post-natal days 1-7). Non-enriched females stereotyped more, had female-skewed litters at birth, and tended to make poorer, flatter nests. Maternal licking and grooming showed large, stable individual differences, but appeared unaffected by enrichment. High levels of maternal stereotypic behavior predicted slower offspring growth, replicating previous findings for farmed mink. Nevertheless, enrichment did not significantly increase infant growth rates nor decrease infant mortality. Due to small sample sizes, our study now needs replicating, particularly to explore the potential benefits of enrichment on nest building, sex ratio effects, and the implications of maternal licking and grooming for offspring stress reactivity. Findings could then apply to endangered mustelids like the European mink.
Keywords: animal welfare; captive breeding; infant mortality; mustelids.
© 2015 Wiley Periodicals, Inc.