LAUSR

sniffing one another’s faeces. Many mammals communicate through smells in their urine. To see whether faeces have a similar role, Courtney Marneweck at the University of KwaZulu-Natal in Pietermaritzburg, South Africa, and her colleagues analysed odours from the faeces of more than 100 wild white rhinos (Ceratotherium simum) in South Africa. Distinct odour profiles were associated with animals’ sex, age and state. For example, levels of the chemical 2,3-dimethylundecane distinguished males from females; nonane defined whether a male was territorial; and 2,6-dimethylundecane indicated whether a female was in a reproductive state. Territorial males that were exposed to artificial versions of these compounds responded accordingly, behaving as if threatened when presented with odours from another territorial male. The results suggest that the animals defecate at communal sites to communicate with each other.