Today copper solutions are commonly used to prevent these filter feeders from attaching themselves to boats and other aquatic equipment. In the future, natural toxins from marine sponges may form the base of solutions used to discourage barnacle growth. At maturity, their legspan averages 10 feet, although it may reach 13 feet. In contrast to their long legs, their bodies are only about 14 inches in diameter. First described to the western world in 1690 by a physician of the Dutch East India company, these crabs live off the southeast coast of Japan.
Leeches are hermaphroditic, which means that a single individual produces both sperm and eggs.
During mating, one leech transfers sperm to the other. Young hatch from a cocoon and, in some species, may spend some time attached to the back of a parent. Sponges can be round, flat, or branched. Many sponges produce toxins which may function to discourage predation, keep other sponges from smothering them, or prevent animal larvae and plant spores from settling on their surfaces. Closely related to octopuses and squids, cuttlefishes can change colors to hide, frighten predators, or communicate with other cuttlefish.