poikilothermic
poi·ki·lot·hermic
adjective
1.
of animals except birds and mammals; having body temperature that varies with the environment
Origin
From poikilo- + -thermic.
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.