'Some nibbling may have occurred': sea otter pictured trying to eat a horn shark

A sea otter off the coast of California caused a splash when it was photographed apparently trying to eat a shark – though it appears it did not manage to complete its meal.

Related: Furry engineers: sea otters in California's estuaries surprise scientists

Photographers Don Henderson and Alice Cahill captured the unusual event, which involved a small horn shark, in Morro Bay last week.

The images were shared by Sea Otter Savvy, a non-profit which seeks to promote “responsible wildlife viewing, awareness of the effect our behaviour can have on sea otters and other wildlife, and a safer, healthier coastal environment for all of us, otter and human alike”.

Michael Harris, of the California department of fish and wildlife, told the website For the Win Outdoors: “To my knowledge … this is the first documented horn shark capture by a sea otter. There are reports of sea otters capturing skates and rays, but this is the first report of a shark. Sea otters will feed on fish, but it’s a very rare observation in California.”

Sea otters, the smallest North American marine mammal, typically eat invertebrates such as sea urchins, clams and crabs.

But as Sea Otter Savvy posted on Twitter: “If you watch sea otters long enough you will see a range of sea life brought to the surface. While fish are not unusual prey for more northern sea otters (Alaska & Russia), they are quite uncommon in California.”

Horn sharks live on the seabed, eating a similar diet to otters with an extremely powerful bite. Whether or not the shark seized by the otter managed to bite back, Sea Otter Savvy noted: “Not surprisingly, while some nibbling may have occurred, the prey was not consumed.”

Harris told For the Win Outdoors he was “fairly certain” the otter was an adult female.