Scientists believe most bottlenose dolphins are ‘right-handed’

27 Nov 2019

Image: PA Media

Similar to other aquatic mammals, bottlenose dolphins show a right-side bias in foraging behaviour.

Dolphins show right-flipper bias, scientists have said.

Studies on one group of dolphins in the Bahamas found they also preferentially use their right eye and echolocating ‘lips’ on their right side while hunting for prey.

A study published in the Royal Society Open Science journal suggests this indicates a specialisation in the left-hemisphere of their brain, the side that processes information from the right visual field.

Similar to other aquatic mammals, bottlenose dolphins show a right-side bias in foraging behaviour, according to Dr Jennifer Kaplan, from the Dolphin Communication Project in Florida, and colleagues.

In Bimini, the Bahamas island closest to the US, the dolphins display a unique behaviour, making sudden sharp turns while echolocating on the bottom for prey.

‘Significant’ bias

Researchers found the animals frequently execute a sharp turn before burying their snouts in the sand. Based on data collected from 2012 to 2018, they found a “significant” right-side (left turn) bias in these dolphins.

Out of 709 turns recorded from at least 27 different individuals, 705 were to the left – right side and right eye down. Only one individual turned right – left side and left eye down – in four out of four turns.

The authors say: “The dolphin brain is capable of integrating visual and echoic information, enabling it to ‘visualise’ an object’s shape through sound alone.

“Thus, these crater-feeding dolphins may be processing and integrating visual and echoic information in their left hemisphere.

“Whether driven by anatomical structure or hemispheric specialisation in sensory processing, a left turn/right-side bias in crater-feeding common bottlenose dolphins provides a strong demonstration of laterality in behaviour.”

– PA Media