The Galapagos Islands' 14 finch species were so crucial to Charles Darwin's theory of evolution that they've been dubbed "Darwin's finches." But more recent voyages have shown that a few of them are Dracula's finches, too.
The sharp-beaked ground finch normally eats seeds, and often abandons arid areas for more hospitable spots during the dry season. But one of its subspecies stays on two arid islands all year, supplementing its diet of seeds with a feast of blood. Known as "vampire finches," they have a unique strategy for stealing blood from seabirds: They pick at wounds on the larger birds' backs, just enough to keep the injuries open and the blood flowing, but not so much that their hosts fight back or fly away.
For more on vampire finches' amazing adaptation — and how they manage to get away with it — check out the video below: