Australian Land Leech

Description:

One of the most hated creatures of the Australian bush is the blood-sucking Australian Land Leech (Gnatbobdellida libbata). Although most species of leech are found in aquatic environments, this one has adapted to life in the moist rainforests and wet eucalypt forests of eastern Australia. When conditions are suitable (moist ground conditions), these horrible relatives of the worm come out onto bushwalking and animal tracks and wait for their victims. They do this by ‘standing’ in an upright position, clasping the ground with their posterior sucker, as per the shot on the left. Chemical sensors and vibration are used to detect an approaching host, usually native mammals or humans. As the unsuspecting victim moves past they reach over and attach themselves with their anterior sucker. Once on their victim they make their way to a suitable vein near the surface, often around the ankle, upper foot or between your toes. The land leech has two jaws and makes a V-shaped incision, blood is prevented from clotting via an anticoagulant and a histamine with improves blood flow directly into the leech. Once attached the leech with fill-up with blood, perhaps tripling its size. When satisfied they drop off the victim and find a suitable niche to digest their meal. After a while the wound becomes itchy and this is usually the first indication that you have been bitten. The itch can continue for a day or two and a large red sore is usually all that’s evident for your blood donation. Leeches do not carry any infectious disease.

Habitat:

The Australian Museum web site says they can grow to 200mm, but the biggest ones I’ve ever seen is 50mm. This was about 30mm long when erect. They can easily be detached by sprinkling salt onto the leech and spaying and good insect repellent around your boots and socks is usually a good enough deterrent to avoid being ‘attacked’ in the first place.