Birds are endotherms. Birds can generate heat internally.

Butterflies are ectotherms. Ectotherms are known as cold‑blooded animals.

A rhinoceros is an endotherm. Most mammals, birds, and people are endotherms.

Foxes are endotherms. They require more food to stay warm.

Frogs are ectotherms. Almost all reptiles, fish, insects, amphibians, and arachnids are ectotherms.

Alligators are ectotherms. Ectotherms are found mostly in warm climates.