arctic ground squirrel

sounds of pika and marmot calls" 2002-10-30 Characteristics of arctic ground squirrel alarm calls Oecologia Volume 7, Number 2 / June, 1971 Why do Yellow-bellied

乌嘴美洲鹃 – Coccyzus melacoryphus (Dark-billed Cuckoo) 灰腹棕鹃 – Piaya cayana (Squirrel Cuckoo) 黑腹棕鹃 – Piaya melanogaster (Black-bellied Cuckoo) 小棕鹃 – Coccycua

集、贮藏大量食物。冬眠期间，新陈代谢速率降低，心跳、呼吸速度放缓，体温甚至能下降到和周遭环境一样的温度。比如，北极地松鼠（英语：arctic ground squirrel）在冬眠时体温可降至-2.9°C，但头与颈会始终保持在0°C以上。在旱季、酷暑时节，一些生活在燥热环境中的哺乳动物（肥尾鼠狐猴）会夏眠。