ed sounds. Sharks have sensitive eyes that can see extremely well in dim light such as most cats. Sharks also are believed to have small amount of color vision. Yet, sharks may not be able to see many details clearly. Fertilization is internal in all sharks, and the males have slight changes of the pelvic fins known as claspers. They act as internal organs which are located in humans. Many species give birth to 60 or more pups in a litter, but most have far fewer. Each egg is enclosed a leathery capsule which at first is fully closed but soon allows a little sea flow in to the embryo. The parents do not take care of the young and in some cases may even eat them. Shark eggs, unlike those of most fish, are fertilized inside the female's body. The male shark has two organs called claspers, which release sperm into the female, where it fertilizes the eggs. Among most species of sharks, the eggs hatch inside the female, and the pups are born alive. At least 40 species lay their eggs outside their bodies.Sharks belong to a group of fish known as Elasmobranchs. Rays and skates also belong to this group. The scientists frequently identify new species of sharks. But sometimes they find that two sharks that had been considered different species are actually the same. -Thresher sharks are long-tailed fish that swim along the surface. They grow to a length of about 20 feet. The Thresher uses its long tail to gather into. Thresher sharks are called named that because of the way that they kill their prey. Which is scaring them then easily taking advantage of them.-Basking sharks are the largest species of sharks known to man. They are measured to be 30 feet long and live in all types of water. This type of shark is known as omnivores because they only eat small animal and plant life called plankton. These sharks usually swim on the surface of the ocean. -Hammerhead sharks, are a strange and odd type of shark, yet, are one of the strange...
