Maternal nest building and choice of nest site are temperature dependent in mink: Parent-offspring temperature conflict?

Abstract

We investigated whether nest building and nest site preference are temperature dependent in female mink. We designed two experiments: in Experiment 1, female mink had access to unheated (7 °C, Room7C group) or heated (25 °C, Heated25C group) nest boxes; in Experiment 2, female mink had free choice of nest boxes at three temperatures (7 °C, 16 °C, and 25 °C). We hypothesised that the progress in nest building would be temperature dependent (Experiment 1), with female mink having a temperature preference, and that this preference would shift toward a higher temperature when giving birth (Experiment 2). Nest building decreased with increasing nest box temperature from Day −3 to Day 7 relative to the day of birth (Experiment 1: P < 0.001; Experiment 2: 7 °C > 16 °C > 25 °C, P < 0.05). In Experiment 1, females in the Heated25C group stayed for significantly shorter times inside the nest boxes than did females in the Room7C group (P = 0.007). In Experiment 2, dams spent the most time in the 7 °C nest boxes and the least time in the 25 °C boxes (P < 0.05). Similarly, dams given a choice preferred not to place their litters in the 25°C nest boxes through Day 7 (Experiment 2, P < 0.05). Offspring placed in 25°C nest boxes weighed 17.5% more than those placed in 7°C boxes on Day 7 (Experiment 1, P = 0.028). When dams were away from the nest, 1) offspring in unheated nest boxes vocalised longer than did those in heated boxes (Experiment 1: P = 0.010), and 2) offspring in 7 °C boxes huddled more than did those in 25 °C boxes (Experiment 1, P = 0.021). These results show that maternal nest building and choice of nest site are temperature dependent, with a potential temperature preference conflict between dams and offspring.