Is a shark a mammal?

Sharks are the most ferocious fish in the ocean, also known as sand fish, mackerel sharks, mackerel people, etc., which existed on the earth as early as 300 million years before the emergence of dinosaurs, has been more than 500 million years, and has hardly changed in the past 100 million years. Living on injured marine mammals, fish and carrion, let's take a look at whether sharks are mammals.

Is a shark a mammal?

Sharks are not mammals. Sharks are a kind of fish, belonging to the fish class, relatively primitive, the way of reproduction is oviparous, and can also maintain a constant body temperature so that they have enough strength to attack quickly, but sharks are not mammals because sharks breathe through gills and do not breast-feed their cubs, while mammals breathe and breast-feed through their lungs.

Is shark viviparous or oviparous?

Sharks are viviparous. Oviparity means "hatching eggs in vivo", that is, fertilized eggs produced by fertilization in animals are left in the reproductive tract of the mother, and the yolk of the egg develops into larvae until the embryo is fully developed. the reproductive tract of the mother will contract to expel the young together with the egg membrane, so the embryos of the oviparous animals are properly protected by the mother, and the survival rate of hatching is more guaranteed than those who give birth to eggs.

What are the characteristics of mammals?

1. Mammals have highly developed nervous systems and senses, which can coordinate complex functional activities and adapt to changing environmental conditions.

2. Oral chewing and digestion have appeared in mammals, which can greatly increase energy intake.

3. Mammals' high and constant body temperature (25-37 degrees Celsius) reduces dependence on the environment.

4. Mammals have the ability to move quickly.

5. Mammal reproduction is viviparous (except protozoa) and breast-feeding, which ensures a high survival rate of offspring.