Читать книгу Extreme Nature - Mark Carwardine - Страница 16

NAME	Amazon leech Haementeria ghilianii
LOCATION	Amazon basin
ABILITY	drinking up to four times its weight in blood

© Werner A Wuttke

No, the biggest blood-sucker isn’t a vampire bat. Vampires, which are native to the tropical Americas, don’t actually suck blood – they lap it up. They find large mammals – most noticeably cows, pigs or horses – make a cut in their skin and then drink the blood. Not being very big (average body length is 6.5–9cm/2.5–3.5in), a single bat only actually consumes a few tablespoons of blood a night, though because of the anticoagulant in its saliva, the prey keeps bleeding for some time after the bat has flown away.

The world’s largest leech, measuring up to 46cm (18ins) does suck blood, however, and a very hungry one can take in four times its body weight before it becomes satiated. Since a large Amazon leech weighs about 50g (1.8oz) – the record is 80g (2.8oz) – that’s a lot more than a few teaspoons of blood. Like the vampire, the Amazon leech feeds on large mammals, which it attacks when they enter water, and it also uses an anticoagulant to keep the animal’s blood flowing. But the leech injects an anaesthetic, too, so that the temporary host is unaware of what’s happening to it.

All leeches are segmented worms – their nearest relatives are earthworms – and all, regardless of size, have precisely 32 segments. A few segments at each end of the Amazon leech are modified into suckers for attaching to prey, and every segment has its own independent nerve centre – hence a leech has 32 brains.