Brazos Bend State Park
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Gator Hatch

Pond Life of Brazos Bend State Park

Segmented Worms: Phylum Annelida

Annelids are segmented worms. Generally, they are long slender, legless, eyeless worms whose bodies are composed of rings. They have soft bodies and thin skin. The most commonly known of the segmented worms are earthworms. Three types of segmented worms commonly found in the ponds at Brazos Bend State Park are leeches, aquatic earthworms, and deros.

Leech, 2 inches long


Leeches are the animals that everyone loves to hate.

Because some of them are known to suck blood, the entire group is despised by the public. Actually most leeches are predators rather than parasites.

Leeches have a long muscular body that can stretch or contract as it moves. They are frequently as long as 3 inches when extended. Their bodies are thin toward the head and thicker toward the tail. They have 2 very strong suction cups, one at each end, and can cling very tightly with them.

Although Leeches are usually black, occasionally pink or brown ones are collected.

Aquatic Earthworms, 7 mm long

Segments of aquatic earthworm magnified 40 X showing gut and hairs.


Aquatic Earthworms are small worms, 5-20 mm long. They have thin, usually transparent bodies with a spiral gut running down the entire length. Their bodies are covered with thin hairs. They spend their time burrowing in the mud at the bottom of the pond feeding on organic material in the mud.

Deros are very tiny worms that make houses for themselves out of bits of plant material. They hold onto these houses with foot-like appendages on the end of their abdomen, and drag them with them where ever they go. The houses make excellent camouflage. The deros looks like just another piece of debris floating in the water. The only way a collector can tell that it is a deros is when it moves.


Deros(Green) in a house made of bits of plant material





Updated: Aug 13, 2011