Hermit crab wood and stone are used by some species). The tip of the hermit crab's abdomen is adapted to clasp strongly onto the columella of the snail shell. Most hermit crabs are nocturnal. Hermit crabs can be divided into two groups: As hermit crabs grow, they require larger shells. Since suitable intact gastropod shells are sometimes a limited resource, vigorous competition often occurs among hermit crabs for shells. The availability of empty shells at any given place depends on the relative abundance of gastropods and hermit crabs, matched for size. An equally important issue is the population of organisms that prey
Spider fighting tournament, with the last two victorious spiders fighting each other in the finale. Spiders used in spider derbies in Singapore come from the species "Thiania bhamoensis" (also called "Fighting Spider"), a jumping spider. The practice has been the subject of a memoir entitled "Spider Boys," and a popular television series in Singapore called "Fighting Spiders." Capturing, admiring, nurturing, and staging fights among these spiders is a popular activity among many young people. The practice had a relatively large financial impact on those young people who participate in these practices both because of the sale value of a strong contender and