ホッキョクギツネ
The average mass specific BMR and total BMR are 37% and 27% lower in the winter than the summer. The Arctic fox decreases its BMR via metabolic depression in the winter to conserve fat storage and minimize energy requirements. According to the most recent data, the lower critical temperature of the Arctic fox is at −7 °C in the winter and 5 °C in the summer. It was commonly believed that the Arctic fox had a lower critical temperature below −40 °C. However, some scientists have concluded that this stat is not accurate since it was never tested using the proper equipment.