The Oklahoma City Zoo and Botanical Garden is proud to announce that three of its expert team members authored an article published in Animal Cognition, a peer-reviewed scientific journal, that highlights how Asian elephants can differentiate quantity by sound. The article was written by Rebecca J. Snyder, OKC Zoo’s director of conservation and science; Lisa P. Barrett, OKC Zoo’s postdoctoral fellow; Rachel A. Emory, OKC Zoo’s curator of elephants and rhinos and Bonnie M. Perdue at Agnes Scott College. Click here to view the article.
New research in Animal Cognition shows that Asian elephants, like African savanna elephants, can choose a greater quantity by using auditory cues. Many animals including insects, birds, mammals, fish, reptiles and amphibians are capable of discerning quantity. The authors of the paper tested this research on two of the OKC Zoo’s Asian elephants; females, Asha, 26, and Chandra, 24, with assistance from the Zoo’s elephant care team. Asian elephants are known to be able to distinguish quantity by using vision, and they have even been shown to discriminate quantity by using smell alone. More recently, African elephants passed the test using their auditory sense—by hearing each piece of food dropped into a barrel they could determine which barrel contained more food.
“We were excited to see if Asian elephants could do this as well,” said lead author and OKC Zoo’s Director of Conservation and Science, Rebecca Snyder. “In the wild, Asian elephants live in forested habitat, so we thought they may be relying more on senses other than sight.”
The researchers presented each elephant with two barrels into which they dropped different amounts of elephant browser biscuits (nutritious diet supplement) one-by-one, each making an audible sound when it hit the bottom. Then, the elephants could make a choice as to which barrel they wanted, and after choosing, they consumed their reward. To control for the possibility that elephants were basing their choice on how much time the experimenter spent at each barrel, the experimenter spent the same amount of time at each barrel. There was a visible condition, in which elephants could see the rewards on top of the barrel, and a nonvisible condition, in which elephants could hear the rewards without seeing them. To watch a video of the experiment, click here.
OKC Zoo’s Curator of Elephants and Rhinos and author on the study, Rachel Emory, was not surprised that the elephants often chose the correct barrel. Emory noted, “Asha and Chandra seemed to be listening closely as food was dropped into the barrels.”
The authors also compared performance of the Asian elephants to that of African savanna elephants who were previously tested at Zoo Atlanta in Atlanta, Georgia, and found that the two species performed similarly. “For both species, as ratio between the barrels increased performance declined. For example, elephants performed better on 1 vs. 4 (ratio = 0.25) and 2 vs. 4 (ratio = 0.50) than they did on 3 vs. 4 (ratio = 0.75). This ratio effect was a bit stronger for Asian elephants than for African elephants,” said author and OKC Zoo postdoctoral fellow Lisa Barrett.
More studies are still needed with a larger sample size from both species to make strong conclusions about elephants’ understanding of quantity. “We especially need more research on elephant cognition that uses the same methods with multiple elephant species to compare species’ abilities,” said Snyder. The authors also note that it would be interesting to extend the study with elephants that experience varying levels of human interaction to determine if different elephant populations rely more or less on certain types of cues.
The Oklahoma City Zoo is home to a multi-generational herd of seven Asian elephants ranging in ages from 54 to 3, and is dedicated to the research and conservation of elephants. Since 2010, the OKC Zoo has provided over $422,000 to support conservation efforts for Asian and African elephants in ten countries. You can help conserve elephants by contributing to the Zoo’s Round Up for Conservation Fund, which is used to support conservation projects around the world.
The Oklahoma City Zoo is open from 9 a.m. to 5 p.m. daily. Advance tickets are required for all guests and ZOOfriends members and can be purchased at okczoo.org/tickets. Zoo tickets are limited each day to ensure safe social distancing among guests. Located at the crossroads of I-44 and I-35, the OKC Zoo is a proud member of the Association of Zoos and Aquariums, the American Alliance of Museums, Oklahoma City’s Adventure District and an Adventure Road partner. Regular admission is $12 for adults and $9 for children ages 3-11 and seniors ages 65 and over. Children two and under are admitted free. Stay up-to-date with the Zoo on Facebook, Twitter, Instagram and TikTok, and by visiting Our Stories. Zoo fans can support the OKC Zoo by becoming a member. Memberships can be purchased at ZOOfriends.org or any place admission is sold in the Zoo’s Entry Plaza during regular business hours. To learn more about this event and Zoo other happenings, call (405) 424-3344 or visit www.okczoo.org.
Snyder, R.J., Barrett, L.P., Emory, R., and Perdue, B.M. (2021). Performance of Asian elephants (Elephas maximus) on a quantity discrimination task is similar to that of African savanna elephants (Loxodonta africana). Animal Cognition, https://doi.org/10.1007/s10071-021-01504-5.