Elephants sniff urine to tell who's who

An African elephant can recognise dozens of kin by the signature smell of urine, and uses its powerful nose to keep track of their whereabouts, according to a new study.

Researchers led by Professor Richard Byrne of the University of St Andrews in Scotland, publish their research in the journal Biology Letters.

A keen trunk coupled with a good memory is essential for the foraging pachyderms, which travel in ever-shifting groups ranging from a handful to several hundred individuals, the study says.

Drawing from developmental research on pre-verbal children, scientists from the UK and Kenya tested the ability of elephants in Kenya's Amboseli National Park to distinguish kin from stranger.

They also devised experiments, called 'expectancy-violation' paradigms, to see whether the animals knew where family members were at any given moment.

They placed individual samples of urine mixed with earth from females along the paths of 36 elephant family groups, and then measured the reactions.

Only female urine samples were used because the social structure of the African elephant Loxodonta africana is matrilineal.

The first female in a group showed very little interest if the urine sample was from an elephant outside its group, but stopped to reach with its trunk if the odour came from a familiar source.

African elephants are able to keep tabs on at least 17 females, and as many as 30 individuals, both male and female, at any given time, the study says.

The lead elephant displayed especially heightened interest if the pungent smell belonged to an elephant that was trailing behind with the family.

This shows the African elephant "can remember where some family members are in relation to itself", the researchers conclude.

"The fact that individuals do not generally walk in the same order when travelling, suggests that keeping track of the location of other elephants could be cognitively demanding," they say.

Byrne and his colleagues conjecture that olfactory kin recognition is made possible by certain proteins found in urine, such as lipocalins and immune system molecules called MHC markers.

Agençe France-Presse