1. Look at the appearance: Crocodile turtles are called real crocodile turtles, mainly because their appearance is closer to that of primitive turtles. The head of the crocodile turtle is pointed, and the upper jaw is olecranon-shaped, with obvious hooks. Their tongues are red, their mouths are relatively large, and there are three raised ridges on their backs, and their nail peaks are obvious. Big crocodile turtles also have many tentacles in their abdomen and long tails.

The small crocodile turtle is also called crocodile turtle. Although there are hooks in the upper jaw, the hooks are not obvious, and the nail peak is not obvious. It looks close to the flat back. Their carapace looks round, with a small number of tentacles in the abdomen. The color of the carapace is gray and the tail is short, but there is a circle of tail spines in the tail.

2. Look at the predation method: Crocodile turtles are lazy by nature and are not good at actively catching food. They usually open their mouths and attract prey through the peristalsis of their tongues. Small crocodile turtles can take the initiative to prey, and have strong predation ability.

3. Look at the origin: Most of the crocodile turtles originate in the Mississippi River Basin, while the small crocodile turtles originate widely, distributed in the eastern and central parts of North America, Central America and Central South America.

Crocodile turtles and small crocodile turtles be raised together, but crocodile turtles are timid and small crocodile turtles are lively, so breeders need to give them enough space to ensure that they will not conflict with each other.