Wardens have spotted 10 rare black-coloured seal pups among England’s largest grey seal colony on the north Norfolk coast.
Grey seals are born white, shedding their fur at about two to three weeks old to expose a grey coat underneath.
But around one in 400 grey seals have a velvety black coat instead, which is revealed when they moult, the National Trust said.
These are called melanistic seals – with melanism being the increased development of the dark-coloured pigment melanin.
The colony at the National Trust’s Blakeney National Nature Reserve in Norfolk is expected to see a record 4,000 new seal pups this season.
Numbers have grown to such an extent in recent years that rangers have had to rethink the way they count the seals born at the breeding ground.
Instead of counting them all individually, they will be counted in one area to give an indication of what is happening across the colony.
The first grey seal pup was spotted at the nature reserve in 1988 and since then it has grown to be England’s biggest colony for the marine mammals, with numbers increasing from 25 youngsters born in 2001 to 3,399 pups in 2019.
This season’s count is ongoing.