How are sharks and crabs different?

Sharks and crabs are both arthropods, but they belong to different groups. Crabs are crustaceans, while sharks are cartilaginous fish. Here are some of the key differences between sharks and crabs:

- Body Structure: Sharks have a streamlined body shape that is well-suited for swimming, while crabs have a more rounded body shape with jointed legs and claws.

- Skeleton: Sharks have a cartilaginous skeleton, while crabs have an exoskeleton made of calcium carbonate.

- Gills: Sharks breathe through gills, while crabs breathe through gills or specialized structures called spiracles.

- Reproduction: Sharks reproduce sexually, with males fertilizing females' eggs internally, while crabs typically reproduce asexually, with females laying fertilized eggs.

- Size: Sharks can range in size from small species like the dogfish shark, which is only about 2 feet long, to large species like the whale shark, which can grow up to 40 feet long. Crabs can also vary in size, with some species such as the coconut crab growing up to 3 feet long, while others such as the pea crab are only about the size of a pea.

- Habitat: Sharks are found in all oceans, from the shallows to the deep sea, while crabs are found in a variety of habitats, including oceans, freshwater, and even on land.