While the average size of organisms decreases with depth, large megafaunal species are well represented at abyssal depths and have an important ecological role (Billett et al. 2001; Ruhl and Smith 2004). Scavenging amphipods living at abyssal depths actually exhibit gigantism (Hessler et al. 1972); they are much larger than typical peracarid crustaceans (Perrone et al. 2002). These organisms are highly mobile, and are adapted to quickly locate and consume large food falls. Their unusual size may be a response to a different set of selective pressures than those affecting smaller sedentary members of the community.