Spiny lobsters tend to live in crevices of rocks and coral reefs, only occasionally venturing out at night to seek snails, clams, crabs, sea urchins or carrion to eat. Sometimes, they migrate in very large groups in long files across the sea floor. These lines may be more than 50 lobsters long. Spiny lobsters navigate by using the smell and taste of natural substances in the water that change in different parts of the ocean. It was recently discovered that spiny lobsters can also navigate by detecting the magnetic field of the earth. They keep together by contact, using their long antennae. Potential predators may be deterred from eating spiny lobsters by a loud screech made by the antennae of the spiny lobsters rubbing against a smooth part of the exoskeleton. Spiny lobsters usually exhibit social habit by being together. However recent studies indicate that healthy lobsters move away from infected ones leaving the diseased lobsters to fend for themselves.