Well, what's so special about these critters?

The stomatopods are extremely interesting because:

They use specialized raptorial appendages to capture and subdue prey by either "spearing" the animals or "smashing" them with heavily calcified clubs. The force of the strike of a large Californian species approaches that of a 22 caliber bullet, and is capable of breaking double layered safety glass. They are, weight for weight, probably the most formidable animals alive.

A stomatopod, Nannosquilla decemspinosa, uses an active, wheel-like motion of its entire body to roll along beaches. It is the only macroscopic creature known that uses active wheel-like motions for locomotion.

Stomatopod strikes are the one of the fastest known movements in the animal kingdom. Although existing in a medium significantly denser than air, their strikes are 10 times faster than those of the land-based Praying Mantis. The raptorial appendages of stomatopod spearers can go from full rest to a speed of 10 meters/second in 4-8 milliseconds.

Stomatopods have the most sophisticated visual system in the world. The stomatopod eye contains 16 different types of photoreceptors (12 for color analysis, compared to humanity's 3 cones). Mantis shrimps can thus see polarized light and 4 colors of UV (ultraviolet) light, and they may also be able to distinguish up to 100,000 colors (compared to the 10,000 seen by human beings).

Stomatopods are the only invertebrates in which individual recognition has been strongly documented for non-mated individuals. This simply means that some stomatopods are capable of distinguishing one individual in the species from other individuals, and then act accordingly.

Stomatopod communication has one of the fastest information transmission rates in the animal kingdom. During aggressive interactions between mantis shrimps, rates of transmission can be as high as 8.6 bits per second, compared to an average of 1.5 bits per second for hermit crabs, 1.4 bits/s for fire ant pheromone trails, and 2 bits/s for the honeybee dance. As a comparison, one study found that human speech has transmission rates of 6-12 bits/sec!

Some stomatopods are monogamous, one of the few invertebrates (or animals in general for that matter) that manifests this practice. Dr. Roy Caldwell notes that he has followed a monogamous pair of Lysiosquillina maculata for nearly 15 years.

Stomatopods are widely-used as an effective way to measure the health of coral reefs. "Stomatopod abundance, diversity and recruitment are very negatively correlated with sediment concentrations of petroleum hydrocarbons and certain heavy metals, and with surrogate measures of sewage and agrochemical runoff contamination " (Steger and Caldwell, 1993; Erdmann and Caldwell, in press).

Web Site Author: A. Sunjian
Site Created February 3, 1998
Site Dedication