The skull, which was discovered at the Gibraltar Point National Nature Reserve, was found by a woman who was walking her dog and picking up litter, according to the Lincolnshire Echo.
When she found the grisly specimen she reportedly “couldn’t believe her eyes”.
“I think it's definitely a washed up seal skull that's been bashed about by the tide,” the woman, who wishes to remain anonymous, said.
“The top part of the jaw is missing and the bottom jaw is out of place by the looks of it.”
She posted photographs of the grisly remains online, with several people trying to work out what it was.
Initial inquiries by The Independent included the suggestion from a London veterinarian that the skull could be the remains of a brachycephalic dog, such as a French bulldog or a pug, which have flat faces and short snouts.
They said from the photographs the creature appeared to have canines, indicating it was from a carnivorous animal. The lack of any discernible eye sockets, led to the suggestion it could have been a malformed puppy.
The plot thickened as the vet said the reddening of the skull could be due to haemorrhage which would suggest evidence of a head trauma, but she also noted the reddening of the skull can also happen after death if the body is left lying on one side so the blood pools.
However, the plot then thinned somewhat after experts from the Natural History Museum and the Grant Museum positively identified the specimen.
The mystery animal from the sea is none other than a common seal.
A spokesperson for the Natural History Museum said: “According to our principal curator of mammals, Richard Sabin, it is a seal skull and it is missing the front part of the skull which holds the upper dentition.
“According to Richard, it’s tricky to identify species from the single photograph online, but the shape of the check teeth appears consistent with the common seal, Phoca vitulina. Common seals are known to occur at Gibraltar Point.”
Experts at UCL’s Grant museum concurred. Zoology curator Tannis Davidson said: "I’ve taken a look at this and its looks like a seal skull: Phoca vitulina.
“The front of the cranium is broken so only the posterior part of the orbit is visible with lack of post-orbital processes suggesting that it is a seal rather than a dog."
She added: “The alignment of the teeth in the mandible are typical of Phoca vitulina as well as the dental morphology.”
The woman who found the skull told The Independent: “I was litterpicking and just walking my dog on the beach. I do a lot of regular litterpicks.
“I suspected it was a seal skull and it does appear to be one.”
She added: “It's quite common for bones and strange things to wash up on our coast just not every day you find a seal skull but loads do get washed up.”
Seal skull found on a beach. Mystery solved.
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