Scientists have discovered a spider in Africa that craves human blood.
This jumping spider actively seeks out mosquitoes that have fed on human blood; it hangs out on tree trunks and buildings, where it stalks its prey, rather than building webs.
From the article:
Lab experiments conducted near Lake Victoria showed the spider preferred female mosquitoes fed with human blood over all other prey, including male mosquitoes, which don't feed on animal blood. Tests of the spider's prey preferences showed it went for blood-engorged female mosquitoes in 83 percent of cases when offered a choice of two similar-size insects. When it came to making a choice based on smell alone, with the two meal options hidden from view, around 90 percent of jumping spiders selected the blood-filled mosquito.
The article says that this is the first known predator that deliberately feeds on vertebrate blood by eating mosquitoes, and goes on to say that this is the only animal known to select its prey based on what the prey has eaten. That apparently does not include humans, unless these scientists have never tasted milk-fed veal.
Although the spider is currently not a threat to humans, there is no speculation yet as to what will happen when the spider realizes the stuff tastes better on tap than in a bottle.