Elephants never forget old pals, says a new study

Researchers at the University of Pennsylvania have also found in their study that just like humans, some elephants are social butterflies while others prefer to stick to a close-knit group of friends.

Past studies suggested that elephants usually live in small groups centred around females and their young while adult males live independently.

However, the latest study found that though males do live apart, females and their young actually have the sort of complex network of friends, relatives and acquaintances normally seen in humans.

Lead researcher Dr Shermin de Silva was quoted by the `Daily Mail` as saying, "Elephants are able to track one another over large distances by calling to each other and using their sense of smell.

"So the `herd` of elephants one sees at any given time is often only a fragment of a much larger social group. Our work shows that they are able recognise their friends and renew these bonds even after being apart for a long time."

The study also found that some are more sociable than others and those who had few friends tended to be loyal to them, while those with a larger circle were less so.

For their research, the researchers studied more than 100 female adult Asian elephants in the Uda Walawe National Park, in Sri Lanka, for 20 months. While many kept the same friends, 16 per cent changed their "top five" associates.

The study found bonds are strong in the dry season and suggested social networks help protect food and water supplies. These are important as elephants eat for 16 hours every day and drink up to 50 gallons of water.

The creatures tended to hang around in larger groups when water was scarce. The bonds were strong enough to drive away unfamiliar elephants away from watering holes.

Dr de Silva added: "Most individuals have a few strong ties as well as a few consistent ties maintained over several seasons with some of their associates.

"Individuals do not mix randomly within the population nor are they always with the same companions, but rather they shuffle amongst a subset of preferred companions."