In a new study, researchers from the University of California, Berkeley, have discovered how vampire bats make friends with strangers. The study, published in the journal "Current Biology," found that vampire bats use a combination of vocalizations and grooming to build relationships with new individuals.

Vampire bats are social animals that live in colonies of up to 100 individuals. They are also obligate blood-feeders, meaning that they must consume blood to survive. In order to obtain blood, vampire bats must bite other animals, such as cattle, horses, and pigs.

Previous research has shown that vampire bats use a variety of vocalizations to communicate with each other. These vocalizations include short, high-pitched calls that are used to identify individuals and longer, more complex calls that are used to convey information about food and danger.

The new study found that vampire bats also use grooming to build relationships with new individuals. Grooming involves licking and scratching another bat's fur. This behavior is thought to be pleasurable for vampire bats, and it may also help to remove parasites and dirt from the fur.

The researchers found that vampire bats that were groomed by a stranger were more likely to cooperate with that stranger in a subsequent task. This suggests that grooming may be a way for vampire bats to build trust and cooperation with new individuals.

The study's findings provide new insights into the social behavior of vampire bats. They also suggest that grooming may be a general mechanism for building relationships in other social animals.

Here are some additional details about the study:

- The researchers conducted their experiments with a group of 16 captive vampire bats.

- The bats were paired up with陌生人 and allowed to interact for 10 minutes.

- During the interaction, the researchers recorded the bats' vocalizations and grooming behavior.

- The researchers then tested the bats' willingness to cooperate with each other in a subsequent task.

- The results showed that vampire bats that were groomed by a stranger were more likely to cooperate with that stranger in the subsequent task.

The study's findings suggest that grooming may be a way for vampire bats to build trust and cooperation with new individuals. This behavior may also be important for maintaining social bonds within colonies of vampire bats.