TOKYO – Soft-shelled turtles have an extremely keen sense of smell that may surpass that of dogs in their ability to perceive subtle differences in odors, Japanese and other scientists have found.

The group published the finding in the online version of scientific journal Nature Genetics.

“Dogs may be more sensitive to smell than soft-shelled turtles, as their noses have a greater surface area. But these turtles may have an advantage over dogs when it comes to sniffing out subtle differences in scents,” Center for Developmental Biology researcher Naoki Irie said.

The latest finding is based on a CDB study on the number of olfactory receptor genes in soft-shelled turtles.

The study discovered the turtles have 1,137 olfactory receptor genes. This compares with 1,207 for rats, which are highly sensitive to smell, 811 for dogs and 396 for humans.

“Different animals have different senses of smell as they live in different environments. The eating habits of soft-shelled turtles may be a factor behind the presence of such a wide variety of smell receptors,” said Kazushige Tohara, a professor at the University of Tokyo.