Cephalopods, Crustaceans, & Other Shellfish Archives - Page 2 of 4 - Oceana

Chambered Nautilus

The chambered nautilus is one of six species of nautilus, the only cephalopods (squids, octopuses, and relatives) that have external shells. Like in most shelled animals, this species can retract completely into its shell when threatened. The chambered nautilus lives in deep waters of the open ocean and is one of very few species of shelled … Read more

American Horseshoe Crab

The American horseshoe crab is not a true crab and is not even a crustacean at all. In fact, this species is more closely related to spiders and scorpions than to crabs, shrimps, and lobsters. As a broader group, horseshoe crabs have been around for at least 450 million years, making them one of the … Read more

Acorn Barnacle

Barnacles, somewhat surprisingly, are crustaceans (like crabs, lobsters, krill, etc.). Unlike most crustaceans, however, adult barnacles are sessile – they can’t move. After a short phase spent as planktonic larvae, barnacles settle, attach to a hard substrate, and never move again. The Acorn Barnacle is one species in a large group of species with the … Read more

Southern Blue-Ringed Octopus

The rings of a southern blue-ringed octopus are particularly vivid when an individual is threatened or agitated. In addition to the bright blue rings, these octopuses are famous for having extremely potent venom that can be strong enough to kill a person. There is currently no known anti-venom to treat a person who has been bitten. The southern … Read more

Red King Crab

Red king crabs are covered with a spiny exoskeleton that provides them some protection from potential predators, but at different stages of its lifecycle, the species is preyed upon by fishes, octopuses, and some marine mammals. Red king crabs are also known to be occasionally cannibalistic. Red king crabs are omnivorous and will eat just … Read more

Queen Conch

The queen conch is a large marine snail that lives in the Caribbean Sea and adjacent waters and is one of the most valuable fishery resources for every country throughout its range. Reaching its maximum length of approximately one foot (30 cm) in three to five years, the queen conch spends its growth resources thickening … Read more

Humboldt Squid

Like many squids, the Humboldt squid grows rapidly and likely lives for only a single year. During that time, it reaches its maximum size, reproduces multiple times, and dies. Humboldt squid reproduce via internal fertilization and lay large egg masses of at least one million eggs. In their short lifetime, females may lay as many as 20 million … Read more

Peacock Mantis Shrimp

Females are also brightly colored but are mostly red. Peacock mantis shrimp are powerful hunters, feeding on hard-shelled invertebrates of all kinds and even some fishes. They are well known for the extremely fast punching motion that they do with their front appendages to kill and break apart their prey. This punch is one of the fastest movements … Read more

Dumbo Octopus

The name dumbo octopus refers not just to one species but to an entire genus of deep-sea umbrella octopuses, noted for their fins that resemble Dumbo the elephant’s ears (of Disney fame). There are at least 15 species of dumbo octopuses, and like all umbrella octopuses, their arms are connected by a web of skin, … Read more

Colossal Squid

The colossal squid is a massive squid that lives in the deep sea surrounding Antarctica, and it is the holder of multiple records. Not only is it the largest invertebrate on Earth, it also has the largest eyes of any animal, larger even than those of the great whales. Human knowledge of the colossal squid … Read more