Published in PLOS One on Wednesday, researchers at the Museum of Natural History in Berlin documented complex social behaviours in a wild group of Vampyrum spectrum for the first time.

Following a family of four, they found the bats greet each other when returning to the nest, share prey, co-parent their young and sleep in tight huddles, among other behaviours.

Lead author Marisa Tietge says she came across a roost by chance in a hollow tree, while studying a different bat species in Guanacaste, Costa Rica. She installed a motion-activated camera in the base of the tree to capture two parents and two pups over three months.

One noteworthy behaviour was a "hug-like" greeting, Tietge says, where bats in the nest would leave their spot to welcome a family member back.

"There's kind of a short wrapping of its wings around the other, like a short hug, then letting go, and then both or all of them go back to the main roosting spot," she said.

Tietge theorizes the hug helps them identify each other based on smell and builds necessary social bonds for survival.