Lobsters are related to crayfish, shrimp, and crabs because they all belong to the same family of crustaceans. These creatures share similar characteristics and are part of the same taxonomic group. They have a similar body structure, with a hard exoskeleton, jointed limbs, and a segmented body. Additionally, they all live in aquatic environments and have a similar diet, feeding on small organisms and scavenging for food. Therefore, lobsters are related to crayfish, shrimp, and crabs, as they all share common ancestry and evolutionary traits.