Mantis shrimp

Did You Know?

• Some saltwater aquarists keep mantis shrimp in captivity; the peacock mantis is especially colourful and desired in the trade.
• The Devonian Eopteridae have been suggested to be early stomatopods, but their fragmentary remains make the referral uncertain.

Description

Mantis shrimp are usually about 10 centimeters long, but the zebra mantis shrimp can grow as large as 38 centimeters. Their carapace only protects the back part of the head and the first four thorax segments. Their colors vary widely, from plain browns to bright, contrasting hues. The second pair of thoracic limbs is built for close-quarters fighting, and the claw shape splits them into two main groups.

Spearers have spiny, barbed-tipped appendages for stabbing and grabbing prey, and this type is the most common. Smashers have a heavily mineralized club for bludgeoning, divided into impact, periodic, and striated regions, and are found in the families Gonodactylidae, Odontodactylidae, Protosquillidae, and Takuidae. A basal group called spike smashers, limited to the family Hemisquillidae, has a less specialized appendage that lacks most spines and can smash but is poor at spearing. A few species have a rare, highly modified hatchet appendage that has not been studied much.

Ecology and life history

Mantis shrimp are long-lived and exhibit complex behaviour, including ritualised fighting and the use of fluorescent patterns for signalling. Many species defend their space from rivals through social behaviours; for example, Neogonodactylus oerstedii performs a posture called the meral spread that appears to indicate fighting ability. They are typically solitary and aggressively defend their burrows, which may be rock formations or self-dug burrows in the seabed.

They are rarely seen outside their homes except to feed or relocate. They can learn and remember well, recognising neighbouring mantis shrimp by visual signs and individual smell. Depending on the species, they may be diurnal, nocturnal, or crepuscular. Most species live in tropical and subtropical waters of the Indian and Pacific Oceans, between eastern Africa and Hawaii.

Spearing species build burrows in soft sediments, while smashing species make burrows in hard substrata such as coral cavities. These burrows serve as retreats, feeding sites, and locations for mating and egg safety. Body size undergoes periodic growth, requiring the animal to find a new cavity or burrow. Some spearing species can expand burrows made of silt or mud.

Stomatopods may have 20 to 30 breeding episodes over their lifespan. Eggs are either laid and kept in a burrow or carried under the female's tail until hatching. Males and females may meet only to mate or may form monogamous, long-term bonds.

Systematics

The earliest clear mantis shrimp ancestors appear in the Carboniferous period, between 359 and 300 million years ago. These ancient forms split into two main groups: Palaeostomatopodea and Archaeostomatopodea, with the latter being closer to today's mantis shrimp, which are all part of the Unipeltata clade. The oldest Unipeltata fossils come from the Triassic. Carcinologist Raymond B. Manning described many mantis shrimp species, and his personal collection is the largest globally, containing 90% of known species; the remaining 10% have yet to be discovered.

Culinary uses

Mantis shrimp appear on menus around the world under many names. In Cantonese cuisine, they are called "urinating shrimp" because they shoot a jet of water when handled. Their cooked flesh resembles lobster more than shrimp, and their hard shell needs pressure to crack. A typical dish involves deep-frying them, then stir-frying with garlic and chili peppers; they can also be boiled or steamed.

In Japan, the species Oratosquilla oratoria, known as shako, is boiled for sushi or eaten raw as sashimi. Along Vietnam's coast, they are called bề bề, tôm tích, or tôm tít, and are steamed, boiled, grilled, or dried, often seasoned with pepper, salt, lime, fish sauce, tamarind, or fennel. In the Mediterranean, Squilla mantis is common seafood, especially on the Adriatic coasts and the Gulf of Cádiz. The Philippines has several names for them—tatampal, hipong-dapa, pitik-pitik, pilantik, or alupihang-dagat—and cooks them like other shrimp.

In Kiribati, they are called te waro and eaten boiled. In Hawaii, unusually large mantis shrimp from the contaminated Grand Ala Wai Canal carry the usual risks of seafood from polluted waters.