The Galapagos Islands are home to some famously unusual animals, but did you know that one of these famous animals is a real-life vampire? The deadly Galapagos vampire finch!
A vampire finch in blood drinking action © Simon Pierce
The terror of the Galapagos
OK, maybe the vampire finch isn’t all that deadly. The vampire finch (Geospiza difficilis septentrionalis) may have evolved a taste for warm blood, but it only drinks the blood of other birds, not human blood. So you’re safe, as long as you don’t have feathers.
But why would an innocent looking finch evolve to drink blood?
Darwin’s Finches
You may already have heard of the Galapagos finches, as they’re famous for helping Charles Darwin understand how evolution happens by natural selection. Today, around 15 finch species are found on different islands in the Galapagos, but Darwin realised that in the past only species of finch must have originally arrived at the Galapagos. As this original ancestor species spread across the islands, it evolved into the 15 descendent species as the finches became adapted to the slightly different habitats they found on each island.
So what was it about the vampire finches’ habitat that caused them to evolve to drink blood?
You can see this ground finch has a thick, short beak to help it break tough nuts and seeds © Robert Stebbings
A beak for blood
One way in which the finch species in the Galapagos have adapted to different habitats is in the size and shape of their beaks. Some finches feed on hard nuts and seeds, and have evolved short, powerful beaks to help them crack nuts. Other finches feed on insects, and have evolved longer, sharper beaks that allow them to nimbly target scurrying prey.
The vampire finch has a sharp beak, as it evolved to mostly eat insects, including parasites that live on other, larger birds. Vampire finches are found on the Wolf and Darwin islands, which are dry and don’t have much water, so scientists think that the vampire finch evolved to drink blood as a way to quench their thirst. And that it was a small evolutionary step from landing on larger birds and using their sharp beaks to peck at parasites, to pecking the larger birds to create cuts, and then drinking their blood.
A gruesome behaviour, but a beautiful evolutionary adaptation.
To find out more about Darwin’s finches, including the vampire finch, you might like to try the following links:
- http://www.livescience.com/32409-whats-so-special-about-darwins-finches.html
- http://www.hhmi.org/biointeractive/origin-species-beak-finch
- http://beautyofbirds.com/vampirefinches.html
by Daniel Swindlehurst
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