Warm-blooded animals have a body temperature, which stays roughly the same whatever surroundings they are in. This temperature however can vary from creature to creature. For example the body temperature of any healthy human is 98.4 degrees Fahrenheit.
However, some creatures are cold-blooded which means that the body temperature varies according to the animal's surroundings. This means that animals, which are cold-blooded, have to live in certain areas suitable for their survival. This is one reason why you never find cold-blooded creatures living in very cold surroundings like polar regions, as they would die of cold because they would not be able to maintain a body temperature suitable for life. Fish, some amphibians and reptiles are cold-blooded animals.