Animal Conservation

Dolphin surprises wildlife experts with an underwater pear tree


Risso’s dolphin was caught on camera performing an unusual underwater “pear tree”, leaving wildlife experts wondering what it was up to.

The dolphin was seen performing the maneuver – suspended vertically with its nose down, fully underwater and slowly spinning – thanks to drone footage used to probe marine mammals off the island from Lewis in Scotland.

Environmentalists say that although there have been sightings of the ‘head-up’ species in other parts of the world, these dolphins had their tails above the water – and they had never seen a full head. previously submerged.

Nicola Hodgins, a whale and dolphin conservation researcher (WDC), said they were unsure why the animal was behaving this way, although one theory is that it could have listened to calls from others. creatures in the water.

Ms Hodgins, who is also responsible for the charity’s policies, said it shows how little is known about the social and cultural life of mammals.

She said it is important to study their behavior to understand their needs and requirements in order to better protect them and their habitat.

We don’t really know what he’s doing … it might just be relaxing and have a few seconds of peace and quiet

WDC has been monitoring Risso’s dolphin population, photographing their dorsal fins as unique as fingerprints, off the coast of Lewis for more than a decade.

The association’s team uses non-invasive techniques to study dolphins, recording individuals remotely from boats.

This year, they used a drone as part of their surveys – with footage capturing the never-before-seen underwater position of the dolphin, said to be at least 20 years old and alone at the time.

Ms Hodgins said: “We’ve never seen this behavior before and we don’t really know what it is doing. We have some guesses as to what this might be.

“It could be the fact that he’s listening, just slowly, and maybe that’s one of the best ways – if your head is on the surface of the water, you won’t hear as much as you can. if you are a few feet lower.

Or “it could just be relaxing and have a few seconds of peace and quiet,” she suggested.

“I did some research and tried to find out if this behavior had been observed elsewhere.

“There is a term known as ‘head upright’ which has been seen in some Risso’s dolphins, in the Mediterranean for example, but on all these occasions the animal is half in the water, half out of the water. the water.

“It’s fascinating to think that there are behaviors and that they have a whole social life that we know so little about.”

Risso’s mothers and calves are seen in the area (Nicola Hodgins / Whale and Dolphin Conservation / PA)

Researchers are starting to gather information about their social lives, she said, because – having photographed them since 2010 – she can recognize the individuals and others they spend time with.

But Ms Hodgins said there was no estimate of the animal population in the UK or Scotland.

The project which began in 2010 aims to bring together so much information about the unusual-looking species – which turn whiter with age due to scars caused by other Rissos and their prey, the squid – off the coast of Lewis.

The region is visited by large numbers of mothers and calves, and teems with squid and octopus, the staple food of Risso’s dolphin.

Evidence gathered led to the designation of a Marine Protected Area at the end of 2020, and WDC now wants to see an effective management plan for the conservation area.

The charity says it doesn’t want to see local fishing such as lobster reduced in the area, but warns large-scale scallop dredging is damaging habitat.

The researchers also found that the species hybridized with bottlenose dolphins and that these hybrid offspring now reproduce on their own.