The Leech Sign

The Leeches of Borneo

09-Jul-00

There was a sign at the rally area under the main lodge. It was all about leeches. I took photos of it because the information was interesting. Here are some images and accompanying text.


To know them is to love them

One of the more infamous inhabitants of the tropical jungle are in fact fascinating creatures, highly specialized and supremely adapted to life in the moist dark understory of the rainforest. As we shall see, they are largely undeserving of their fearsome reputation.

Leeches belong to the phylum Annelida, and are distantly related to earthworms.

They are hermaphrodites, and have segmented bodies, no legs, and a sucker at each end of the body, which they use to attach themselves to substrates and "loop" along

The sucker at the thinner or 'head' end surrounds a mouth compromising well-developed jaws with small teeth inside them.

When a leach locates its prey, it punctures the skin using salivary glands producing an anticoagulant to regulate blood flow. This is the reason why leech bites may continue to bleed several hours after the leech has been removed. A leech may absorb several times its own weight in blood before dropping off. It is thought that one meal can last up to six months or more. Favorite prey of terrestrial leeches includes most mammals such as pigs and deer, and ground living birds.

Different Kinds Of Leaches:

There are at least nine species of leech in Borneo, including freshwater species such as the large buffalo leech, 'lartak' or 'lintah', found mostly in muddy water and lowland or coastal areas frequented by buffaloes. Two terrestrial species of leeches are commonly encountered in the Danum Valley Conservation Area:

The Tiger Leach (Haemadipsa picta)

Known locally as 'timtang' or 'pacat daun' (leaf leech), because it is usually found on leaves of lower vegetation. Can grow to about 4cm (1.5") long when stretched out, and sports alternating yellow/orange and black stripes. Bite can be felt.

The Brown Leech (Haemadipsa zeylanica) or 'limatok'.

Dark brown or black in colour, and shorter than its striped cousin. Most often seen on the forest floor. Bite painless..

Some Popular Misconceptions:

• Leeches leave their mouthparts behind if you pull them off in the middle of a meal - FALSE. It is Perfectly OK to do this.


• Leeches scent or smell their prey - FALSE (can't read the explanation, but remember from the guide that they sense body heat).


• Leach Bites hurt - SOMETIMES (again cannot read image; but remember from the guide that some species saliva includes an anesthetic).


• There are more leeches in wet weather - PATRTLY TRUE More are certainly in evidence after a heavy rain. (cannot read the rest).

Medicinal uses:

In the 19th century leeches were used extensively in the west to reduce blood pressure and remove infection. nowadays they are being reared in laboratories for their anticoagulant secretions, which are used in operations such as heart surgery. There is no evidence that leeches were ever applied medicinally in Borneo.

How to escape being a member of the Danum Valley Blood donors club...

• Wear long trousers tucked into socks when in the forest or better still use leech socks available in the shop.


• An insecticide like Baygon sprayed onto clothes will help repel leeches.


• If a leech is on your clothes or skin, it can be removed by flicking it off when it is in the loop position, or by burning it with a cigarette, or by rubbing salt on it. If it sticks to your fingers try scraping it off onto a tree or leaf.