Nature Bulletin No. 101 February 1, 1947
Forest Preserve District of Cook County
William N. Erickson, President
Roberts Mann, Supt. of Conservation
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
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
The roundworm goes round and round.
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Update: June 2012