Scientists investigating the massive deaths of seals with distinctive spiral wounds found evidence that it could be cannibalism that killed them. Authorities previously blamed the death of 86 seals between 2009 and October 2014 on boat propellers because of the markings.
Researchers at the Sea Mammal Research Unit (SMRU) in Scotland observed a grey seal killing and eating five young seals. The carcasses were left with distinctive spiral wounds similar to those washed ashore.
"It grabbed the pup by the scruff of the neck and dragged it over 20m (about 66 feet) to a shallow freshwater pool," the SMRU said.
"The adult then climbed on top of the pup, forced its head under water and held it until its struggle subsided."
For the next 10 days after the sighting, the researchers found nine more dead seals with similar injuries. Coincidentally, there was also sightings of the adults in areas where the carcases were found. Twelve of the total 14 young seals killed by the adult have spiral wounds starting from the head down to the body, according to BBC News.
"The wound pattern seen in the grey seal pups at the Isle of May clearly resembled those that have been recorded as corkscrew wounds on previous grey and harbour seal cases in Scotland," the report said.
The act of cannibalism was also recorded in Denmark and Germany, suggesting that it might be common than previously thought. Grey seals are known to feed on sand eel, cod and other fish.
Marine Scotland is not fully convinced of seal cannibalism, although it acknowledges that it might be a key factor in the number of seal deaths. It will continue its investigation into ship propellers, the Herald Scotland reported.
"The clusters of 'corkscrew' seal deaths were unusual and worrying. In common with many of the creatures that live in our seas, seals are animals that are loved by the public," Environment Secretary Richard Lochhead said in a statement.
"Marine Scotland will continue to monitor our seal population for further injuries and any evidence about the causes."
