Warm-Blooded and Cold-Blooded Animals

Cold-blooded animals are those whose body temperatures are regulated by their environment, and Warm-blooded animals are those whose body temperatures are kept relatively constant by internal mechanisms. Along with the way their body temperatures vary, another main difference between these types of animals is that warm-blooded animals require more food. The terms "cold- 
blooded" and "warm-blooded" are misleading because cold-blooded animals' blood is not necessarily cold, it just varies based on the temperature of the environment. More accurate terms are "ectothermic" instead of "cold-blooded" and "endothermic" or "homeothermic" instead of "warm-blooded." Another term for ectothermic animals is "poikilotherms," which means animals that  
have varying body temperatures.There are several advantages to being endothermic — greater stamina, having only one set of body enzymes that works optimally at a set temperature and the ability to increase body temperature during freezing weather. A spider that is caught in a blizzard will freeze solid, but a human being has at least a chance of survival. Ectothermic animals need to maintain several sets of enzymes for their biological processes because enzymes are sensitive to temperature, but endothermic animals can maintain one set.

Examples

The vast majority of mammals and birds are warm-blooded, and almost all reptiles, fish, insects, amphibians and arachnids are cold-blooded. There are some exceptions, however, and some animals that have characteristics of both types. For example, bats and mole rats are mammals, but their body temperatures can vary according to their environments, especially when they are not active. Certain insects, such as hawk moths and some bees, can raise their body temperatures by beating their wings. Some fish have internal mechanisms that help keep their brains and eyes from becoming too cold, which might impair their function.