SRINIDHI V last edited by
Are Shrew and Humming bird cold blooded?
Sarthak Basak last edited by Sarthak Basak
Hummingbirds and shrews hatch naked and cold-blooded (poikilothermic, body temperature dependent on the surrounding environment).
They don’t become warm-blooded (homeothermic, capable of maintaining a stable body temperature regardless of environmental conditions) until their feathers mature enough to create an insulating layer over their skin. They can return to a limited form of poikilothermy as adults when they need to conserve energy, entering the state of torpor overnight or under severe stress.
This qualifies hummingbirds and shrew as heterotherms.