Research reveals dolphins, like humans, can be right- or left-handed

Dolphins can be left- or right-handed just like humans and exhibit this preference when foraging for food at the bottom of the sea floor, a study has found.

Of 27 individual dolphins studied, only one seemed to favour its left-hand side.

According to the researchers, this likely indicates a predominant specialisation in the left side of the dolphin brain, which processes information from the right eye. 

Biologist Jennifer Kaplan of the Dolphin Communication Project and colleagues observed common bottlenose dolphins hunting for prey in Bimini, The Bahamas.

The marine mammals use a technique called ‘crater feeding’, in which they swim slowly along the sea floor, scanning it using their echolocation. 

When they detect something, they bury their beaks into the sand to catch prey — a move that the Bimini dolphins often precede with a sudden, sharp turn.

Based on observations of this practice made between 2012 and 2018, the researchers found the dolphins had a significant bias towards their right sides, executing turns that placed their right sides and eyes down to the sea floor.

In fact, among 27 dolphins who in total made 709 turns, 705 turns — 99.4 per cent — favoured their right-hand sides.

All of the four right turns were accounted for by a single individual that seemed to favour its left-hand side.

Of 27 individual dolphins studied, only one seemed to favour its left-hand side (stock image)

According to the researchers, the findings likely indicate a predominant specialisation in the left side of the dolphin brain, which processes information from the right eye

‘The dolphin brain is capable of integrating visual and echoic information, enabling it to “visualise” an object’s shape through sound alone,’ the researchers explained.

‘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.’ 

The full findings of the study were published in the journal Royal Society Open Science. 

A BRIEF HISTORY OF UKRAINE’S DOLPHIN MILITARY UNIT

A dolphin unit capable of carrying out marine missions was set up by the Soviet Union in Crimea in 1973 at the height of the Cold War.

Out of a specialised training centre at the Black Sea port of Sevastopol, Soviet handlers trained a number of the sea mammals over several decades.

The programme’s military sea mammals were capable of planting bombs on ships, finding underwater mines and could even attack divers with knives and guns strapped to their heads, according to some reports.

A dolphin unit capable of carrying out marine missions was set up by the Soviet Union in Crimea in 1973 at the height of the Cold War. Pictured is a soviet diver with one of the dolphins during training

After the collapse of the USSR the dolphin unit was handed over to Ukraine’s military in the early 90’s.

The programme contuned until 2014 when Russia annexed Crimea and captured the dolphins.

Some believed Moscow was planning to retrain the dolphins as Russian soldiers.

A source told Russian agency RIA Novosti that engineers were ‘developing new aquarium technologies for new programmes to more efficiently use dolphins underwater’.

On May 14, Borys Babin, the Ukrainian government’s representative in Crimea, revealed the dolphins had died in Russia.

He claimed that the military mammals refused to follow orders or eat food provided by the Russians.