Leeches are predatory creatures that feed on fluids they suck from their victims.
They have strong jaws and mouthparts so they can break through the victim's skin. Anesthetic in their saliva stops the victim feeling the bite. Anticoagulant in their saliva stops the victim's blood from clotting.
Leeches only feed on the solid parts of the blood they injest, eliminating the fluid component as quickly as it can.
Leeches live in moist areas. They can swim. Out of water they move by streching their head forward and attaching the mouth to the surface and then looping their body forward and gripping with a sucker in their tail.
Leeches
Leeches on the track near Burgess Falls at Hazelbrook.