Vampire Bat Sensors

Vampire bats seem like something out of a horror film so read on only if you are brave enough…

In South America, where they are common, vampire bats drink the blood from sleeping cows, goats and birds. They’re the only known mammal that survives solely on blood, and they need to drink it almost every day to survive.

Like other bats, they feed only at night and they have excellent eyesight enhanced by acute hearing and an ability to emit high-pitched sounds that help them navigate. Their teeth lack enamel, which keeps them constantly razor sharp and allows them to delicately tear through the hide of a sleeping animal without waking it.

Within minutes of sinking its teeth in an animal's flesh, an adult vampire bat can drink half its body weight in blood. But first they must find a vein, helped by a major adaptation: heat-sensing ability, which allows them to "see" a vein at night.

In his Discover blog, Ed Yong touts vampire bats’ abilities:

Mythology imbues the vampire bat with supernatural powers, but its real abilities are no less extraordinary. Aside from its surprising gallop and its anti-clotting saliva, the bat also has a heat-seeking face. From 20 centimeters away, it can sense the infrared radiation given off by its warm-blooded prey. It uses this ability to find hotspots where blood flows closest to the skin, and can be easily liberated by a bite.

Researchers have known for years that pits on vampire bats' noses allow them to detect blood vessels because they radiate heat. But no one knew exactly how this occurred.

Now, UC San Francisco and Venezuelan researchers have discovered the bats’ secret: a sensitive, heat-detecting molecule covering nerve endings on their noses called TRPV1.

TRPV1 molecules can also be found on pain sensing nerve fibers in the human tongue, skin or eyes. They allow people to detect the chemical capsaicin in chili peppers and experience the burning tinge of spicy food.

Described in the journal Nature, the discovery highlights how small changes to genes in the genome of a species can contribute to major evolutionary adaptations over time—in this case, allowing the vampire bat to detect infrared heat from their prey, helping them efficiently find and feed on blood.

The work also adds a piece to a larger puzzle related to human health and drug design because these same molecules are involved in pain sensation, such as that associated with touching a hot object, or hypersensitivity to heat after injury and inflammation.

Vampire bats are about more than horror or mythology—they may play a part in pain relief!

Image: Acatenazzi/Wikimedia