Gill Sinclair's picture

Grey seals

Observed: 29th November 2009 By: Gill Sinclair
S159 Neighbourhood Nature - course completeThe Mammal SocietyThe Vincent Wildlife Trust
Mammals expert
Pup2 2009
Melanistic5
Description:

Gorgeous melanistic grey seal and possibly its pup (pup looks like it's moulting to a dark pelage).
The adult was a couple of hundred yards from the pup, but as the pup has started to moult it's probably weaned and the melanistic adult could be mum, ready to mate and go back out to sea.
Two questions:
Does anyone know what the frequency of melanistic individuals is in the population (either the UK population or the global population)?
Does being melanistic disadvantage the seal in terms of hunting? I assume that the spotted/blotched pelage of most true seal species is an adaptation which breaks up the animal's outline underwater, but many eared seals have solid, sometimes quite dark coats.

Identifications
Species interactions

No interactions present.

Comments

the naturalist man's picture

Melanistic grey seal

I am afraid I can not say what the proportion of melanistic animals are in the grey seal population. All I can say is I've been involved in the national survey of grey seals in Britain, during which I saw thousands of grey seal, and never a black one amongst them. Keeping this in mind note this female has survived long enough to have at least one pup, indicating it can not be too detrimental to survival.

Therefore, I suspect melanism is extremely rare. Anyone else know the proportions?

The Sea Mammal Research Unit in St Andrews may know if you want to contact them. They carry out the annual grey seal census on behalf of NERC (Natural Environment Research Council) AKA the British government.

http://www.smru.st-and.ac.uk/

http://www.nerc.ac.uk/

Graham Banwell

Visit the iSpot Yorkshire forum for information on events, issues and news relating to 'God's own country'
http://www.ispot.org.uk/forum/8411

Gill Sinclair's picture

Melanistic grey seal

I have been visiting Donna Nook for 10 years now, and have also seen grey seals in Scotland, Wales and Canada, but this is the first black one I've seen.

I searched the internet for 'melanistic grey seal' and 'black grey seal' (also tried with grey spelt gray!), and I was amazed to find only 4 references to melanistic grey seals - one (a photo on Flickr) (March 2006) did not mention a location, one referred to a pup cared for by RSPCA East Winch in March 2007, another was an adult spotted in Norfolk in January 2009 (so could even have been the same animal) and the fourth was an animal from Wadden Island, Netherlands in March 2009. The RSPCA East Winch web page said they'd cared for 6 melanistic pups since 1988.

Thanks for the advice about the Sea Mammal Research Unit - I'll contact them. But in the meantime it looks like these seals were quite a rare spot and I feel privileged to have seen them (along with the thousands of other people who visit Donna Nook each year
:-))

Gill Sinclair
OU Certificate in Contemporary Science
www.gillsinclair.net
Twitter @Gill_Sinclair

Gill Sinclair's picture

Not a melanistic grey seal? :-/

I've had a reply from SMRU and it seems I was getting excited over nothing:-/

"Both photos are of pups, neither is an adult! Black pups are quite common although there may be regional differences in the frequency of occurrence. Also, black pups are pretty much always males. I don't know of any records of a black female pup. I do not know whether the frequency of all black individuals in a colony has ever been recorded.

Although these seals are very dark, possibly completey black, I am not certain that they are technically 'melanistic' which implies an abberant variation from the normal pattern where some or all parts are black rather than the normal colour. Rather, they are just dark or black-coated individuals. This may be incorrect and is, at best, splitting hairs in terminology.

Most adult male grey seals are much darker than females and, although these pups are dark early in life, they may 'pale up' to an extent as they get older."

Oh well, they're still the 'blackest' grey seals I've ever seen:-)

Gill Sinclair
OU Certificate in Contemporary Science
www.gillsinclair.net
Twitter @Gill_Sinclair

the naturalist man's picture

Black seal pups

Well you learn something new every day on iSpot!

Thanks for contacting the experts. They will not be melanistic as it is a genetic condition and can not, therefore, 'pale up' with age. There will be high levels of melanin in the fur, hence the black colour but they are no more melanistic than a black cat is. To be truely melanistic the skin would also be very dark.

Graham Banwell

Visit the iSpot Yorkshire forum for information on events, issues and news relating to 'God's own country'
http://www.ispot.org.uk/forum/8411