cold-blooded animals

Animals, such as reptiles, fishes, and amphibians, that cannot control their body temperature and therefore become sluggish in cold weather. (Compare warm-blooded animals.)

Note

Cold-blooded animals are often seen sunning themselves to warm up.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.