What Is “Seal Finger”? The Horrible Infection That Sailors Have Feared For Hundreds Of Years

Evolution really popped off the day it made a seal. The playfulness of a dog with the attitude of a fat happy cat who occasionally gets dolphinesque zoomies. What’s not to love? Seal finger, that’s what.

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Yes, approach these friend-shaped foes on the beach and you risk getting a serious bacterial infection that sailors have feared for hundreds of years. Known as seal finger because of its prevalence among those working with seals or seal meat, we didn’t unmask its true identity until 1991.

Seal finger is a kind of infection that develops after a person is either bitten by a seal, or handles seal products when they have a cut on their hands. Historically it’s been common among sailors, fishers, divers, biologists, and vets, and it used to be an illness that came with serious consequences.

What are the symptoms of seal finger?

The leading symptom of seal finger is pain. In fact, the pain could be so severe that sailors would request the affected finger be cut off so that they could carry on working and not lose wages.

That pain is accompanied by swelling that can extend to the entire hand, blowing it up like a latex glove. The infection can attack the joint, too, and without prompt treatment stiffness and loss of function can be permanent.

What causes seal finger?

Seal finger is thought to be the clinical manifestation of infection with a bacterium called Mycoplasma phocacerebrale. It was identified as the primary cause in 1991 after it was detected both in a painful bite on a human hand and inside the mouth of the seal that bit it.

It’s a normal part of the microbiome found in a seal’s mouth and nose, but in a human hand it can cause chaos. The good news? It can be treated with antibiotics, but prompt diagnosis and the correct course of treatment is crucial to making a good recovery from seal finger.

So, if you see a plump seal pup on the beach, just remember: keep your hands to yourself. Oh, and if seal finger isn’t enough to put you off, might we draw your attention to the fact that seals have nails – just take a look at this cursed pinnipedicure.