There's multiple differences between the endotherms and the ectotherms, with the most important being:
- The endotherms maintain a constant body temperature, while the ectotherms's body temperature fluctuates with the environmental temperature.
- The endotherms have developed protection (hairs, feathers) from the outside influences, while the ectotherms do not have such accessories.
- The endotherms are warm-blooded, while the ectotherms are cold-blooded.
- The endotherms are usually bigger if the climate is colder, while the ectotherms are usually bigger if the climate is warmer.
- Endotherms are the mammals and the birds, while ectotherms are the reptiles and most of the invertebrates.