This eight-inch-long mantis shrimp, left, and the author engaged in a gentle 
tug of war over some tidbits of squid. The mock battle took place in the 
waters off Saint Croix; the author never quite succeeded in luring this rare 
species, Lysiosquilla glabriuscula, completely out of its burrow, below left. 
Iridescent color spots on the posterior appendages (uropods) of Hemisquilla 
ensigera californienses. below, can be used to startle potential predators. 
AJex Kerstitcn 
one of their burrows can testify. I 
have more than once retracted my 
hand from an unsuspected coralline 
domicile with the point of a mantis 
shrimp claw embedded in my finger — 
and with the fierce defender, less than 
two inches long, dangling from my 
hand. Divers are said to have had their 
fingers cut or even sliced off by in- 
dividuals of a large species of mantis 
shrimp (up to ten inches in length) 
that occupies burrows in muddy sub- 
strates off southern California and 
Mexico. 
Other notable characteristics of 
these ancient marine creatures are 
their bright coloration and elaborate 
fighting behavior, particularly in 
coral-dwelling species. Oval flaps pro- 
truding from anterior and posterior 
appendages (antennal scales and uro- 
pods, respectively) are often iridescent 
blue, red, or yellow and fringed with 
conspicuously colored hairs (setae). 
Body segments are often edged in bril- 
liant red, and background body col- 
oration may vary from chartreuse, em- 
erald, carmine, speckled brown, 
orange brown, or lemon yellow to 
black with yellow stripes — even 
among individuals of the same species. 
In some species, particularly those in 
less aggressive families, all individuals 
are similarly colored. The function of 
different body colors among individ- 
uals of a species is not known, but 
such variation may allow longtime 
neighbors to recognize each other and 
hence avoid fights, may confuse pred- 
ators, or both. 
All mantis shrimps have an inden- 
tation on the inside of each raptorial 
claw. In the most aggressive species, 
this indentation is marked with a bril- 
liantly hued "eyespot,” which can be 
orange, vermilion, royal purple, pow- 
der blue, yellow, rose pink, or ma- 
genta. In other species, especially 
those belonging to less aggressive fam- 
ilies, the spots are pale green or white. 
While body coloration varies consid- 
erably among individuals of some spe- 
cies, the color of the eyespot on the 
claws is identical on all individuals 
within a particular species. 
In one of their most conspicuous 
threat displays, mantis shrimps lower 
and spread their claw's, exposing the 
eyespots; at the same time the other, 
smaller maxillipeds (usually yellow, 
but sometimes white or iridescent blue 
white) are spread wide, and the head 
is reared back, with the antennae and 
antennal scales extended to the side. 
This display, used with interlopers, po- 
tential predators, and prospective 
mates, serves both to suddenly show 
the eyespots and to increase the ap- 
parent size of the shrimp. 
Many organisms, including butter- 
flies and fishes, are also known to star- 
tle predators by suddenly exposing 
conspicuous eyespots on some part of 
their body. The spots on the claws 
of the mantis shrimps, however, serve 
more than one function. The unvary- 
ing color of these spots within a par- 
ticular species suggests that they con- 
vey information on species identity. 
Several species of mantis shrimps with 
similar morphologies often live in the 
same local habitat. The most aggres- 
sive species bear the brightest-colored 
spots. It is advantageous for members 
of an aggressive species to have some 
identifying, warning characteristic so 
that members of subordinate species 
can recognize and avoid them; thus 
the dominant shrimp is required to 
engage in fewer potentially damaging 
fights. The subordinate shrimp also 
benefits from recognizing the spots 
of the dominant species, as it can avoid 
a fight it would probably lose. Fur- 
thermore, members of subordinate 
species benefit from being less colorful 
because brightly colored spots could 
elicit an attack from a member of 
a dominant species. 
In addition to the eyespot display, 
mantis shrimps direct aggressive be- 
havior against other stomatopods that 
is remarkable for its rapidity and in- 
tensity. The shrimps smash opponents 
with the armored bases of the claws 
and spear them with the opened 
blades. These animals fight to the 
death in some cases, and individuals 
bearing characteristic wounds are fre- 
quently collected in the field. Most 
of the blows are not lethal, however, 
because each opponent rolls up into 
a ball, thrusting its armored tail to- 
ward the other like a shield. The op- 
ponents' blows frequently strike each 
other’s shields, but rarely cause dam- 
age. Each of the coiled shrimps threat- 
ens and strikes over its shield, and 
39 
