A Black-chinned Honeyeater collects hair from a Koala for nest-building material. Photo: Cyril Ruoso/Minden Pictures

Despite their cuddly appearance, koalas aren’t shy about using their sharp claws to defend their territory. (Ask this lady.) But they seem to have made an exception for honeyeaters. When it’s nest-building time, this Australian family of birds likes to land on the slumbering marsupials, rip out their fur, and use it as insulation. And the koalas don’t mind a bit.

In what he claimed was the first documentation of the behavior, UCLA biologist Martin Cody described a Yellow-faced Honeyeater's harvest in 1991. “The bird flew to perch on the koala’s head, neck or shoulders, plucked the hair vigorously from it, attending particularly to the longer hair on or around the ears,” he wrote. It took the honeyeater about two minutes to gather up a good beakful. Then it flew back to its construction site, added the fur to the nest, and returned about five minutes later for another haul. “During these ministrations the koala was apparently unperturbed,” Cody reported.

Birders have also noticed the interactions, which seem to only benefit one creature and mildly bemuse the other. Amateur photographer Kerry Vickers recently caught a Black-chinned Honeyeater loitering near a napping koala in southern Australia. The plucky bird finally zeroed in on its butt, waking the marsupial up in the process. But given that koalas can sleep for up to 18 hours a day, it's hard to be mad at the hard-at-work honeyeater.

Black-chinned Honeyeaters gathering fur from a sleeping Koala to line their nest at Chiltern-Mt Pilot NP on Monday morning #birds #WildOz pic.twitter.com/Td87iqBG0d — Kerry Vickers (@kerrybv1) August 17, 2017

While you won't see it happening to a koala, you don’t have to travel Down Under to see this kind of bird behavior. If you’re in the Eastern United States, keep an eye out for Tufted Titmice next time your family dog takes an outdoor nap—they’ve been known to rob Rover of some fur for insulation. Chipping Sparrows are even bolder: They'll yank hairs straight from a horse’s mane, Audubon's field editor Kenn Kaufman says.

People also need to remain on the lookout—honeyeaters and titmice have been known to steal human hair on occasion. If it happens to you, take a cue from koalas and just keep calm. Oh, and be sure to get video.