Elephants have jumbo memories

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A Sussex behavioural ecologist has proved the old adage that an elephant never forgets. Research by Karen McComb from BIOLS found that African elephants have complex social networks and can recognise the calls of more than 100 of their 'friends' even after a number of years.

Until Karen published her findings in Animal Behaviour, scientists had rejected the idea on the basis of a jumbo's brain size compared to smaller creatures.

Karen and her research assistant, Lucy Baker, have spent years listening to and recording the calls of about 100 elephants. They learned to recognise different family groups by looking at holes and tears in the elephant' ears, marks on their tusks and the way they moved.

During trips to Kenya's Amboseli National Park - ideal because animals there are used to being watched by people - the two researchers recorded the low-pitched 'contact calls' that female African elephants use to announce themselves.

The calls are unique to each elephant and can carry for miles. They are of such low frequency that they are inaudible to the human ear, which can hear only the accompanying harmonic tones.

After noting which elephants met often and which were strangers, Karen and Lucy played the calls back to 27 elephant families and watched their reaction.

When elephants knew the caller well, they called back. If they knew the caller slightly, they listened but did not respond. But if the call was unfamiliar, the elephants became agitated and defensive.

Karen found that elephants could recognise members of at least 14 other families from their calls, which suggested that each could remember around 100 other adults.

The memory of a call appeared to be long-lasting. When the call of an elephant that had died two years earlier was played back to her family members, they called back and approached the sound.

Such extensive networks of vocal communication have not been demonstrated in any other mammal, Karen believes. Her research has previously focused on lions and two species of primate.

Karen will be presenting her findings at the Experimental Psychology Seminar on Monday (4 December). Entitled 'Vocal communication and social knowledge in African elephants', the talk takes place in the BLR (EP 3.9) from 1.00pm to 2.00pm.