London: Just like humans, bats too nurture lifelong friendships, according to scientists.

These nocturnal flying creatures bond closely with family and friends, a five-year study of over 20,000 roosting observations in Germany has revealed.

Their social structure is as strongly bonded as that of pachyderms, dolphins and certain primates including chimpanzees, all of whom can maintain enduring friendships, the journal Proceedings of the Royal Society B reports. Gerald Kerth of Greifswald University, Germany and his team of researchers said their study provides new insights into complex animal societies.

Multi-level structure

"Our study reveals a multi-level social structure in wild bats, which resembles that of elephants, dolphins and some primates, including humans, who keep social relationships despite their regular splitting and merging into a variable number of groups," they said.

All the wild bats were marked with small microchips, allowing for the recording of their daily roosting behaviour with automatic data loggers. This revealed surprisingly stable social sub-units in which both related and unrelated females formed long-term social bonds.