Immunity, Mimicry, and Protection

by S. F.

In an environment dominated by predators, self-protection is of paramount importance to reef dwellers. Marine scientists have found many different protection strategies.

Perhaps most intriguing is the cleaner shrimp, an animal no creature will eat because it's recognized as a valuable friend. These shrimp perch on a coral outcrop and begin a complex dance. Reef creatures seem to recognize the ritual as a sign that "the doctor is in," so to speak. Normally dangerous larger reef animals such as grouper or moray eels appear and become docile, allowing the cleaner shrimp to comb over their bodies, excavate dead tissue from their mouths, and enter their gills in search of parasites. The fish leave clean and free of parasites, and the cleaner shrimp has enjoyed a meal.

Other creatures enter partnerships with animals that are too dangerous to attack. The clownfish is always found in the company of a sea anemone, frequently nestling in venomous tentacles that would ordinarily kill or wound most animals. The clownfish covers itself with a mucus secretion that protects it from the anemone's stings; in return for using the anemone as a safe haven, the clownfish chases off creatures that are immune to the sting of the anemone's tentacles and attempt to feed on it.

Blending into the background is another strategy used by many animals on the living reef. Bright colors and markings are common ways by which animals mask themselves in sun-dappled waters. The pencilfish or seahorse normally resides in the buoyant grass beds that frequently form on the leeward side of coral reefs. Its camouflage is so detailed that even the appearance of the carbon- dioxide-filled sacks that keep the sea plant afloat is reproduced.

Ocean Planet Exhibition Floorplan

gene carl feldman ( (301) 286-9428
Judith Gradwohl, Smithsonian Institution (Curator/Ocean Planet)