one meal, which lasts approximately 2040 min, the
leech removes about 5-l 5 ml of blood, which amounts
to approximately ten times leech body-weight. This is
regarded as one of the largest meals taken by any living
creature relative to its own size. Satiated leeches are
much less active and tend to hide for periods of 12-18
months, during which they digest their meal and do
not bite.7 The neuronal co-ordination of leech movements
and behavior is the subject of intensive research
by neurobiologists.* Interestingly, the array of neurotransmitters
in leech neurons and ganglia is similar to
that found in mammalian brains.8,9