November 2007

Highlight of the month was a visit to the Grey Seal calving beach at Donna Nook in Lincolnshire.

Grey seal pup (Halichoerus grypus)

Grey seal pup (Halichoerus grypus)

The pups are born in laguno (a thick white foetal coat) which they retain for 2-3 weeks.

Grey seal pup (Halichoerus grypus)

Grey seal pup (Halichoerus grypus)

They grow very fast, gaining weight at a rate of about 2kg per day, sustained entirely on a diet of the richest milk of all mammals. Grey seal milk contains 53% fat, with 67% solids, and resultantly has the consistency of thick, melted ice-cream. By comparison, human and cow's milk contains on average only 4.2% and 3.6% fat respectively.

Grey seal pup suckling

Grey seal pup (Halichoerus grypus)

pregnant female Grey seal (Halichoerus grypus)

The females give birth throughout November and there were still several heavily pregnant females present when I visited in mid-November.

pregnant female Grey seal (Halichoerus grypus)

The larger males are also present on the beach, biding their time for the females to become receptive.

bull Grey seal (Halichoerus grypus)

Mating occurs immediately after the pups are weened (3-4 weeks old).

bull Grey seal (Halichoerus grypus)

You don't need a massive lens to get photos of the seals here. They are very close to the path.

Donna Nook, Lincolnshire

October 2007

2007 Diary Index

December 2007