Olive ridley turtles prefer mates of similar size: Study

Rushikulya, discovered as a mass nesting site in 1994, has since become a focal point of olive ridley conservation in India.
| Photo Credit: Special Arrangement

A new study has revealed that olive ridley sea turtles tend to select mates of similar size, indicating a pattern of size-assortative mating. The research, conducted jointly by scientists from the Zoological Survey of India (ZSI) and the University of Michigan, has established a significant positive correlation between the body sizes of mating males and females.

The two-year study, carried out at the Rushikulya rookery off the coast of Odisha – one of the world’s most prominent mass nesting sites for the species – involved the tagging and biometric measurement of 134 mating pairs. The findings have been published in the peer-reviewed journal Ecosphere.

The study was authored by Ashis Kumar Das, Sandeep Kumar Mohapatra, and Basudev Tripathy from ZSI, along with Anshuman Swain and Anil Mohapatra from the University of Michigan.

“Larger females, capable of laying more eggs, and larger males, possibly offering physical advantages, appear to influence this size-based mating preference,” the researchers noted in their findings. Observations of frequent scar marks on females and the presence of multiple males attempting to mate with individual females suggest intense competition during the breeding process.

“These findings provide important insights into the reproductive behaviour of olive ridley turtles, with potential implications for conservation strategies,” said Dr. Dhriti Banerjee, Director, ZSI. She emphasised the urgency of addressing threats to the species, including high sea mortality in the Bay of Bengal, and noted that the study was funded by the ZSI.

Rushikulya, discovered as a mass nesting site in 1994, has since become a focal point of olive ridley conservation in India. Dr. Tripathy, a co-author of the study who has been monitoring the beach for nearly three decades, said that the number of nesting females has seen a marked increase due to sustained conservation efforts.