The mammal kingdom is a world awash in odors, which pepper habitats like billboards along a freeway. And, like billboards, scents are often used as advertisements of sex or identity, as a pair of Czech zoologists recently found in a study of wild white rhinoceroses. White rhinos spend roughly a minute snuffling dung piles of strangers, compared with a 20-second sniff over feces of familiar rhinos, report the researchers in the journal Animal Cognition.
It's the first time southern white rhinos' dung-smelling habits have been recorded in the wild, the scientists say. Scent is particularly important for white rhinos, whose poor eyesight means a sharp sense of smell plays a prominent role in communication. Rhinos were also much less likely to remain alert when smelling a recognizable male rhino's droppings, perhaps because they then went in search of the familiar bull.
Poop isn't the only way that these animals communicate - but it's an easy signal to study, the zoologists point out, as opposed to collecting, say, urine. Rhinos return to common dung piles (think "Jurassic Park's" Triceratops droppings mound, but smaller) to mark their territory, ensuring that both the message persists and that the researchers had a constant supply of fresh feces.