Experiencing Animal Minds by Julie Smith

Author:Julie Smith
Language: eng
Format: epub
Tags: NAT039000, Nature/Animal Rights, SCI075000, Science/Philosophy and Social Aspects
Publisher: Columbia University Press
Published: 2012-11-26T16:00:00+00:00

EXTENSIVE LONG-TERM MEMORY

Elephants are legendary for their memory. Older elephants, particularly long-lived matriarchs, accumulate and retain memories from a lifetime of varied experiences that have adaptive consequences for their families. When investigators played recordings of lion roars of one to three lions to thirty-nine elephant families in Kenya’s Amboseli National Park, matriarchs over sixty years of age were much more likely than younger matriarchs to accurately access the potential danger revealed in the three-lion roars and lead their families to defensive behaviors (McComb et al. 2011).

Probably most noteworthy of elephant memory is their long-term spatial-temporal memory, which is important because they can range extensively. One study of African elephants documented movement of 625 km over a period of five months (Leggett 2006). The most advanced type of spatial memory is that which is location independent, where the mind works like a GPS instrument with a memory of how to find location X while starting from location A, B, or C. In adding the temporal element, the individual remembers how characteristics of the distance locations change on a seasonal basis. For example, during a severe drought that threatened the welfare of all elephants in the Tarangire National Park in Tanzania, elephants were forced to find forage and water outside the park in unfamiliar territory. Members of two clans led by old matriarchs followed the matriarchs to areas outside the park where the matriarchs had experienced a similar drought thirty-five years previously and retained the memory of where forage and water could be found (Foley, Pettorelli, and Foley 2008). The survival of elephant calves in these clans depended on the matriarchs’ memories of places to find water and food outside the park. Another study on detailed, spatial-temporal memory plotted elephant movements from a foraging environment that was drying up, to an area 200 km away where there had been rainfall; the elephants arrived within three days after the start of rains (Viljoen 1989).

Detailed social-acoustic memory is another area in which elephants arguably outperform humans. Playback experiments of recordings from family members at Amboseli revealed that elephants could recognize individual calls of one hundred elephants from 1.5 km away. What is especially noteworthy is that these calls were recognized even with degradation of the individual acoustic signatures to a fraction of that present at close range (McComb et al. 2000). For reference, try recognizing someone’s voice with 90 percent of the sound frequencies deleted.

Elephants also have impressive social-chemical memory with regard to individual urine signatures. Now here is an area where even your pet dog or cat outperforms humans. In a remarkable display of memory, male elephants recognized their mother’s urine decades after they had been separated (Rasmussen 1995; Rasmussen and Krishnamurthy 2000)—a memory feat most likely beyond that of the best sniffer dogs.

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