Mantis Shrimps: Stomatopoda

The behavior of mantis shrimps is defined by their raptorial limbs. Species with toothed or spiny limbs grab and stab their prey and are called spearers. Spearers lie in wait at the entrance to their burrows in mud or sand and wait for a soft-bodied fish or shrimp to come within range. Mantis shrimps that use their raptorial limbs like clubs are called smashers. Smashers actively search for prey, usually animals with hard bodies or shells, crippling them with powerful blows. They drag their smashed victims into hollows among rocks and coral before they begin eating. Depending on the species, resting animals plug the entrance to their burrow with rocks or with their raptorial limbs or tail.

Some species of mantis shrimps are nocturnal (nahk-TER-nuhl), or active only at night, especially on moonlit nights. Others are diurnal (die-UR-nuhl), or active during the day. Still others species are crepuscular (kreh-PUS-kyuh-lur), coming out only just after sunset or before sunrise.

Most mantis shrimps live alone, but males and females will come together briefly only to mate. Males and sometimes females will actively seek a mate. Males perform elaborate mating behaviors to attract the attention of the female. Females will accept one or more males as mates during this time. In a few species, males and females mate for life, a period that may last 15 to 20 years. These life-long mates share one burrow. The females tend to the eggs, while the male hunts for himself and his mate.

Males and females mate belly to belly. Males deposit sperm directly into the female where it is stored in a special pouch just inside the opening to her reproductive organs. The eggs are fertilized inside her body just as they are being laid. The eggs may not be laid right away. The female may choose to wait until ocean currents are available for dispersing the eggs. Eggs are glued together in a mass and take anywhere from 10 days to two months to hatch. During this time the female carefully tends the eggs and is guarded by the male. The hatchlings may leave the burrow immediately, or remain in the burrow for a week to two months.

Newly hatched mantis shrimps have long slender bodies and bulging eyes. They pass through several distinct developmental stages in about three months before reaching adulthood. Some species are benthic (ben-thik) and start out on the sea bottom. Others are pelagic (peh-LAJ-ihk) and immediately set off in the open sea. All species eventually develop into pelagic larvae (LAR-vee) or young and settle to the bottom as post-larvae. Postlarvae are very similar to the adults in both shape and behavior.