Groundhogs spend the winter hibernating in a specially dug hibernation burrow , their breathing and heartbeats slowed to a snail 's pace , their body temperatures not too far above freezing .
土拨鼠在一个特别的冬眠洞穴中冬眠度过冬天，它们的呼吸和心跳慢到和蜗牛差不多，体温比冰点稍高一点。
Marine scientists measure its abundance by dragging a sledge equipped with video cameras along the seabed and counting the number of holes ( a well-maintained burrow being the sign of a happy prawn ) .
The researchers could thus put three females into a burrow and allow them to compete yet , by ensuring that only one of those females had mated with a fertile male , they could be sure that all the grubs in a burrow were hers .
