Jaw Animals: Micrognathozoa

During their search for food, jaw animals move their head slowly from side to side, while the fibers on the head beat food particles toward the animal's mouth. Food that reaches the mouth is quickly grabbed by the bottom jaws, dragged into the mouth, and processed by the main jaws.

When they move, jaw animals either crawl or swim. While swimming, they move slowly in a spiral. When crawling, they glide slowly on the bottom. If disturbed, a crawling jaw animal stops and attaches to the bottom by using a sticky pad on its belly.

Jaw animals produce two kinds of eggs: a thin-shelled type and a thick-shelled type. Scientists believe the thin-shelled eggs are made by asexual reproduction and that the thick-shelled eggs are made by sexual reproduction, even though males have never been seen. One possibility is that jaw animals produce dwarf males that live only for a very short period and therefore have not yet been found. Another possibility is that jaw animals hatch as males and then quickly develop into females. Asexual (ay-SEK-shuh-wuhl) means without and sexual means with the uniting of egg and sperm for the transfer of DNA from two parents.