By Laura Geggel
Elephants are known for their impressively long trunks, but perhaps less well known is the large number of genes that code for their sense smell.
In a study of 13 mammals, African elephants were found to be superior sniffers, possessing the largest number of genes associated with smell — five times as many as humans and more than twice that of dogs.
“Rats had the record for the largest number of [these] genes,” said the study’s lead researcher Yoshiihito Niimura, a researcher of molecular evolution at The University of Tokyo in Japan. “Elephants have much more. It’s almost double, so it’s very surprising.”
The findings support other research on the pachyderm’s superior sense of smell. African elephants can smell the difference between two tribes living in Kenya: the Maasai, whose young men prove their virility by spearing elephants, and the Kamba, farmers who usually leave elephants alone, reported a 2007 study published in the journal Current Biology.
Elephants also use their sensitive sense of smell to forage for food and identify family members. Female African elephants are only able reproduce for a few days every three years, and research suggests that males can smell when a female is receptive to reproduction, said Bruce Schulte, head of the department of biology at Western Kentucky University in Bowling Green, who was not involved in the study.
“When you watch the animal, even in captivity, the trunk is constantly moving. It’s constantly checking out the environment,” Schulte told Live Science.
In the study, the researchers looked at the number of olfactory receptor genes in each mammal. These genes code proteins that reside in the nasal cavity and bind to odor molecules. Nerve cells then relay the information to the brain, which classifies the smell.