RICHARD FREEMAN: GIANT LEECHES: THE SQUIRMING HORROR

One of the inconveniences of our past explorations in the jungles of Sumatra have been leeches. One evening in 2004, whilst on our way to the lost valley, we picked 100 of the little suckers off our legs as we sat around the campfire. I still bear the marks of leech bites from the Sumatran expeditions of 2003-2004 and got some fresh ones this year when I returned.

Jon Hare was particularly repulsed by the creatures and one even found its way into Chris Clark’s mouth! Imagine the horror of a giant leech then. The crawlers in Sumatra were only a couple of inches long but the South American giant leech is 18 inches long!

Haementeria ghilianii inserts a 6 inch proboscis into its mammalian prey in order to drink their blood. This mega leech can live as long as 20 years and was first discovered in 1849. The monster was thought to be extinct since none had been collected since 1893. However, Dr Roy Sawyer discovered a pair in a pond in French Guyana in the mid 1970s, one of these named ‘Grandma Moses’. This individual founded a leech breeding colony at the University of California-Berkeley and produced more than 750 offspring.

More than 46 medical, neurological and natural history research publications were based on data from specimens reared at the breeding colony. Some important discoveries from these offspring include the characterisation and purification of several proteins with an anticoagulant and antimetastatic effect, including hementin, which destroys human fibrin blood clots; charting connection of nerve cells; and functional morphology of salivary and nerve cells. Following its death, ‘Grandma Moses’ was deposited in the collections of the Department of Invertebrate Zoology, National Museum of Natural History at the Smithsonian Institution.

Film of one of these impressive monsters can be seen here
http://fto.co.za/the-biggest-leech-ever-huge
The related Americobdella valdiviana from Chile can exceed 12 inches in length.

Campsite stories are told of a blood-sucking monster near the town of Sharon in Vermont, USA, deep in the Downer State Forest in an 800 acre woodland camp know as Camp Downer. At Camp Downer there is a canoe pond constructed in the 1930s by the Civilian Conservation Corps, and close to an island in the pond a giant leech is said to lurk; a leech weighing over 300lbs!

A story told to scare children at the camp? Who knows? It might be interesting to investigate though.