Humans love quirks. For example, eyebrow slashes, pup scarves, or TikTok moves with no practical use. Most of us don't invent these things. We see them, we copy them. Voilà: instant trend.
And we’re not alone. Animals copy each other, too, but usually for survival. Chimps share food tricks. Birds mimic songs. But occasionally, they just … go rogue.
Take the orcas spotted in 1987 wearing dead salmon like fishy hats. No hunting benefit, no health perk, just a splash of underwater drama.
Yet despite how amusing or intriguing these seemingly “useless” behaviors are, scientists haven’t spent much time digging into why animals pick up trends that don’t serve any obvious purpose.
Back in 2010, one bold chimp at a sanctuary in Zambia started a curious trend: she stuck a blade of grass in her ear... and left it there. No reason. No itch. Just jungle chic.
Soon, seven others joined in, because why not? Even after the original “grassfluencer” passed away, the quirky habit lived on, with a few chimps still rocking the look today.
Flash-forward, and a team of researchers from Utrecht University, Durham University, and other institutions noticed another chimp group in the same sanctuary getting even more creative. Not only did they wear grass in their ears, but they let it dangle from their behinds, too. A fashion statement? An inside joke? No one knows. What’s striking is that no other chimp groups at the sanctuary adopted the style, even though they shared the same environment.
Edwin Van Leeuwen and his colleagues therefore interpreted that, though it might look pointless, these leafy accessories suggest chimps have their own kind of culture and possibly their own idea of what’s cool.
The research team, led by Van Leeuwen, meticulously tracked which chimps adopted the habit over time and noticed something key, they weren’t inventing it from scratch. The behavior likely spread through social copying, not coincidence.
But when the team zoomed in on what sparked the trend, they stumbled on something truly intriguing ...
“Both groups where chimps put blades of grass in their ears had the same caretakers," Van Leeuwen said. "These caretakers reported that they sometimes put a blade of grass or a matchstick in their own ears to clean them. Caretakers in the other groups said they did not do this. The chimps in the one group then figured out to stick the blade of grass in another place as well.”
In the wild, chimpanzees are busy surviving; they have no time for quirky hobbies like wearing grass in their ears. But in captivity? Life’s a little easier. With less food hunting and danger dodging, chimps get more free time ... and apparently, get more creative.
Researchers noticed chimps copying each other’s odd habits, like ear-blade grass styling or rear-end accessorizing. No obvious purpose, but the behavior spread, just like human trends do.
Humans are great at copying, even the weird stuff, and some scientists think this is the secret sauce behind our cultural evolution. Most animals don’t bother mimicking seemingly meaningless behaviors, so they keep reinventing the wheel.
But this study shows chimpanzees might also be into social imitation for the sake of it.
But what if this chimp fashion wasn't entirely pointless? While Van Leeuwen and his team initially saw the grass-in-orifice trend as simply a quirky behavior with no obvious function, they’re now entertaining a more meaningful possibility: social bonding.
Copying someone’s odd habit, like dangling grass from your ear, might be a chimp’s way of saying, “I see you, I like you, and I want in.”
Just like humans mimic trends to fit in, chimps might be using these leafy accessories as tiny acts of connection, building friendship and belonging in their groups.
The study is published in the journal Behaviour.
Source: Utrecht University