WHAT DOES IT MEAN WHEN WE SAY AN ANIMAL IS COLD-BLOODED?

Generally, cold-blooded animals don’t use their own energy to warm themselves and maintain their body temperature. Warm-blooded animals heat themselves with energy from food, so they need to eat more regularly than cold-blooded animals. The only two warm-blooded groups are mammals and birds. Reptiles, amphibians, fish and invertebrates are cold-blooded. Many cold-blooded animals increase and control their temperature by basking in sunlight. Others, especially invertebrates, require their environment to be warm enough before they are able to move quickly. Many cold-blooded animals need to hibernate if they are to survive cold winters.