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
Tapajós hermit little hermit, and the Tapajós hermit was believed to be most closely related to the black-throated hermit. In 1996 it was suggested that the Tapajós hermit was entirely invalid, and actually represented hybrids between the reddish and streak-throated hermits. In 2009 this hypothesis was shown to be incorrect, and the Tapajós hermit was instated as a valid species. Tapajós hermit The Tapajós hermit ("Phaethornis aethopygus") is a species of hummingbird in the family Trochilidae. It is found in the south-eastern Amazon in Brazil, and its common name refers to the Tapajós River, which forms the western border of its distribution.