25 October 2012 Last updated at 07:55 ET

Experts' joy at birth of first Farne Island twin seals

Both pups may not survive, experts say

Wildlife experts believe the first ever twin seals have been born on the Farne Islands, off the Northumberland coast.

The grey seal pups were spotted by National Trust ranger David Steel, who had been monitoring a pregnant seal.

Multiple births in grey seals are "extremely rare" and no records exist of any having been born on the islands.

The Sea Mammal Research Unit at the University of St Andrews in Scotland has asked for DNA tests to verify the pups have come from the same mother.

Mr Steel, who has worked with the seal colony for 12 years, said: "Over the weekend, a lone heavily pregnant cow seal was discovered on the secluded south beach.

"By Monday, the female, still on the secluded beach, and still by herself, had given birth, but to our surprise, not to one pup but possibly to two.

'Biologically possible'

"On the small rocky beach, two pups were together, wet and bloody, with the mother in attendance.

Grey seals

• Grey seals are Britain's largest living carnivore
• Britain has 36% of the world population of grey seals around its shores
• Pups weigh 14kg at birth but quickly gain the blubber they need because their mother's milk contains 60% fat

Source: BBC Nature

• Watch a grey seal pup take its first swimming lesson
• Born to dive: Find out how seals have adapted to avoid the bends

"It was evident that both had just been born and with no other female in this area of the island."

Ailsa Hall, acting director of the Sea Mammal Research Unit at the University of St Andrews, said: "As far as I'm aware it's extremely rare for twins to be born in grey seals and to my knowledge this hasn't been directly recorded anywhere.

"It is biologically possible for seals to conceive twins, but the female would usually abort one foetus prior to birth as she wouldn't have the resources to feed both pups.

"In this case, National Trust rangers monitored one female in the cove where the pups were born for a number of days before finding two pups very close together, clearly very soon after pupping.

"Should the pups survive the rangers can take DNA sample from the pups and we will test it just like you would a human to see if the pups came from the same mother."

The Farne Islands are known for their huge seal colony and around 1,500 pups are born there each year.