Nature Bulletin No. 101   February 1, 1947
Forest Preserve District of Cook County
William N. Erickson, President
Roberts Mann, Supt. of Conservation

****:HAIR SNAKES

Farm boys have more fun than city boys. Every farm boy has watched 
the "hair snakes" sometimes found wriggling in drinking troughs for 
horses and cattle, or in puddles on a country road. They and their 
fathers will argue obstinately that these are hairs, from a horse's mane 
or tail, that turned into snakes. Phooie!

Hair snakes are not snakes at all. They are roundworms. There are four 
common groups of worms here: annelids, which include earthworms 
and sewage-sludge worms; tapeworms; flatworms; and roundworms. 
The last three are called the "Lower Worms" and many of them are 
parasitic in other animals.

The adult hair snakes, called "Gordian worms" by biologists because 
frequently found in tangled masses suggesting the Gordian knot of 
mythology, do resemble animated horsehairs or fine wires. They are 
covered with a thick tough skin and teel like the wet gut leader on a 
fishing line. They have a pair of eyes and many fine bristles along the 
body which are sensitive to touch. Having no mouth, they cannot eat 
although they may live for weeks or even months. They are freeliving -- 
only in the young stages are they parasitic.

The female lays a white thread-like string of eggs, sometimes several 
feet long and containing millions of tiny eggs, often found along the 
shores of streams and lakes, or on aquatic plants. After hatching, the 
tiny young bores its way into some aquatic insect such as the mayfly 
larva where it passes through one stage of its development. It may 
remain there until the insect is eaten by a beetle or a fish. Or, if the 
insect dies, it may find its way into the body of a grasshopper, a cricket, 
or a beetle, where it completes the second larval stage and becomes an 
adult worm.

If this second insect "host" falls into a brook or pond, the worm breaks 
through the body wall of the insect and seeks a mate. Otherwise it 
breaks through, falls on land, and may be swept into a body of water, or 
a puddle, by rain. Once we saw two boys, both sons of zoologists, 
having a swell time dropping grasshoppers into a tub of water and 
betting on whether a hair snake would emerge, thus completing the 
cycle.

The roundworm goes round and round.