Tortoise, commonly known as tortoise, is one of the most widely distributed and numerous tortoises in China. Brazilian red-eared turtle, commonly known as Brazilian turtle, is named after two thick red stripes on both sides of the back of the head. The grass turtle is regarded as the top grade of food tonic and medicine tonic, while the Brazilian turtle is recognized as an ecological killer in the world, and there are obvious differences between them.

The tortoise body is rectangular, the carapace is slightly raised, and there are three longitudinal edges with obvious edges. There are black olives on the top of the head, some are blue, the skin in front is smooth and the scales in the back are fine. The abdomen is flat, the male is slightly concave, and there is a notch at the back end. The neck, limbs and bare skin are grayish black or black olive.

Male turtles are small in size, long in tail and smelly. When they are sexually mature, their carapace and bellybutton are black, commonly known as inking, and the olive green stripes on their skin fade and turn black. However, the shell of the female turtle ranges from light brown to dark brown, with a dark brown abdomen, a short tail and no peculiar smell.

The most obvious feature of Brazilian tortoise and grass tortoise is that there is a red mark on the "ear" side of Brazilian tortoise, and the head of grass tortoise is yellowish brown. Brazil's glans penis is small, the nose and mouth are blunt, there are yellow-green longitudinal stripes on the head and neck, and there are 1 red patches behind the eyes.

The tortoise shell is flat, each shield has a round green pattern, and the trailing edge is serrated. The bellybutton is light yellow, with black ring patterns, like copper coins, and the patterns of each turtle are different. The trailing edge is not serrated. There are plenty of webbed toes and fingers. Every Brazilian turtle has a different personality. Some individuals are fierce and aggressive, but others are docile and timid.