Indeed, one of a shark's favorite meals seems to be a shark smaller than itself. For this reason, sharks that swim with other sharks do so only with ones of the same size. Female sharks that are ready to release baby shark pups go into areas they do not usually visit such as estuaries. They do not feed for several days while in the estuary pupping. Ther e is another reason baby sharks do well in estuaries.
Estuaries are river mouths.
Plants and algae make their own food, but all animals have to eat some other living things, plant or animal, to live. It is natural for big sharks to eat other smaller sharks or seals or bony fish. Humans and Sharks Humans have hunted many kinds of large predators almost to extinction. Until recently, we did not understand their importance in the food chain. Initially, we looked at them as competition since we often hunted the same prey they did.