Reptiles are a relatively broad group of animals, including snakes, lizards, crocodiles, turtles, etc. These animals all share some key characteristics:
1. Cold-blooded: Reptiles are "cold-blooded animals". They cannot regulate their own body temperature and usually rely on the temperature of the external environment to maintain their body temperature.
2. Skin: Their bodies are covered with scales or cuticles, which help them reduce water loss, protect their bodies, and provide them with good camouflage.
3. Limbs: Most reptiles have limbs, although some snakes and lumbopods have gradually reduced or completely lost them during evolution.
4. Oviparous: Most reptiles are oviparous, laying their eggs in the environment rather than hatching them inside the mother's body.
5. Respiration: Reptiles breathe in a variety of ways, but most of the more common reptiles use their lungs to breathe.
These are some common characteristics of reptiles, but of course there are also some special species that have some minor differences to a certain extent.
