Isopods inhabit all marine habitats down to 7280 m depth but with few exceptions species have restricted ranges. Four feeding categories are recognised: detritus feeders and browsers, carnivores, parasites, and filter feeders. They range in size from less than 1 mm to Bathynomus giganteus at 365 mm long.
The Giant Isopod (Bathynomus giganteus) is the largest known isopod species of deep-sea bottom-feeding crustaceans. Although it resembles common woodlouse, it can reach up to 36 cm in length. This impressive primitive crustacean has large anterior eyes with a wide binocular field. Bathynomus giganteus lives at depths of 600 m.
Giant isopods are abundant scavengers distributed throughout the Gulf of Mexico and Caribbean Sea. Though less abundant, giant isopods are also found along the eastern coast of the United States as far north as Georgia.
Giant isopods are scavengers and predators. Specimens in aquaria have survived 8 weeks between feedings. It is hypothesized that this may be an adaptation for carrying its brood, which would be severely impacted by a full stomach. Its large size may serve as an adaptation to low and sporadic food availability by increasing fasting time because greater fat reserves can be maintained.
References: File # 107