No Happy Feet here—for the first time, vampire bats have been filmed drinking blood from penguins.
Documentary filmmakers with BBC Nature recently captured common vampire bats feeding on a colony of Humboldt penguins—including babies—on the coast of southern Peru, near the Atacama Desert. (See penguin pictures.)
Scientists already suspected that vampire bats feed on penguins—there’s been evidence of bite marks on some penguins’ feet, for instance—but no one had actually witnessed it, producer Matthew Gordon told BBC Nature‘s website.
“As we scanned the colony using the infrared LED, the team observed the penguins reacting strangely to something on the ground, they nervously pecked and showed clear signs of agitation,” he told BBC Nature.
“We then fixed our cameras onto one area and waited. Finally, after several hours the team noticed glimmers of light reflecting from the vampire’s eyes as it darted around the penguins’ feet.”
But the BBC footage doesn’t curdle the blood of vampire bat expert Gerald Wilkinson, a biologist at the University of Maryland, College Park. “It’s not a surprise—it’s what they do,” he said.
Common vampire bats—which are widespread throughout tropical Latin America—generally snack on anything bigger than a medium-size rodent, usually feeding on livestock, Wilkinson said.
But what is surprising about the BBC video, noted James Eggers, director of education for the nonprofit organization Bat Conservation International, is that common vampire bats prefer mammals, not birds such as penguins.
There are two other species of vampire bat in Latin America that feed only on birds, but they live in wetter climates, Eggers said. It’s likely that a nearby sea lion colony attracted the bats to the area, Wilkinson added.
Finding blood is life-or-death for vampire bats, which need a daily dose to survive. This need has given the bats a unique adaptation: it’s the only mammal that can use its leaf-shaped nose to detect heat in other animals.
Once a vampire bat finds an animal, it hops about—sometimes comically, Eggers said—sensing places where warm blood is coursing closest to the skin’s surface, which are usually extremities such as the feet, fingers, and ears.
Watch National Geographic’s video of vampire bats feeding.
The bat then uses its supersharp teeth to make a tiny incision, lapping up the flowing blood until it’s ingested its weight in blood. Suddenly too heavy to fly, the bat then urinates most of the blood, hanging on to the nutrient-rich blood cells. (See “Vampire Bats Hunt by Sound of Victims’ Breath, Study Says.”)
When all’s said and done, the bat’s tidy work leaves almost no trace, thanks in part to the tiny incision and anticoagulants in their saliva. In fact, most of the animals are asleep during the whole process.
“I was a little disappointed that the title of the video said vampire bats attack penguin chicks—there’s no intention of harm,” Eggers said.
People have a tricky relationship with vampire bats, which can carry rabies and have bitten people while they sleep. However such cases are rare, and in many incidences, the bite is a result of the bats’ other prey being removed, Eggers said. (Rabies is a mammalian virus and can’t be transferred to birds, which includes penguins, according to the U.S. Centers for Disease Control and Prevention.)
Due to concern over rabies, some governments in the Caribbean and Central America have encouraged people to kill vampire bats, but often people don’t know what the three species look like and end up killing any type of bat, Wilkinson noted. That’s why Eggers’s organization works to educate people about vampire bats. (Explore an interactive about Panama’s bats.)
For instance, research shows that the anticoagulant in vampire bat bat saliva may be an effective way to break up blood clots that lead to strokes in people.
In that sense, Eggers said, “vampire bats are literally saving our lives.”
The vampire bat footage appears in the BBC One series Penguins: Spy in the Huddle.