The strangest creatures on Earth aren’t in the forest, desert, or sky – they’re all under the sea. To see the true oddities of the ocean, though, you typically have to venture thousands of feet deep. Except in the case of the ocean sunfish, of course, which proudly displays its bizarre appearance right on the surface.
Recently, one of these ocean-dwelling oddballs was photographed by NOAA in the Greater Farallones National Marine Sanctuary. Though an eye-catching species all on its own, this individual stood out even more, as the massive mola was doing its very best shark impression at the time.
“Duunnn dun… duunnn dun… wait a second, that’s no shark—it’s a mola mola! These ocean giants roam the seas in search of their favorite food, jellyfish. This one was spotted impersonating a shark,” the NOAA Office of National Marine Sanctuaries wrote in a Facebook post.
In the animal kingdom, many species employ mimicry as a survival mechanism or hunting tool. Tree ocelots, for example, a species of wild cat, mimic the cries of baby tamarin monkeys to lure in adults for a meal.
Meanwhile, the spicebush swallowtail caterpillar takes on the appearance of bird droppings in the early stages of life to deter potential predators.
For ocean sunfish (also known as mola mola), however, the similarities in their appearance to sharks don’t provide any use at all. Except maybe keeping nosy humans at bay. “This photo is a coincidence in looking like a shark from the surface,” Jennifer Stock, a spokesperson for the marine sanctuary, told Newsweek.
“They eat jellies, so mimicking a shark is not something they do. It only looks like a shark to humans above the water, so no ecological mimicry is going on.”
Ocean sunfish are among the world’s heaviest bony fish
At first glance, the ocean sunfish is an intimidating sight, especially when doing its shark impression. The world’s heaviest bony fish, the sizeable sea creature grows to a maximum length of 10 feet and weighs in at an unbelievable 5,000 pounds.
A peek beneath the surface, however, will reveal that the ocean sunfish couldn’t be less frightening, even at its staggering size. Circular in shape except for its large fins, the mola mola looks a bit like a science experiment gone wrong – what happened to the tail end of its body?
Believe it or not, though, its half-a-fish appearance is just how the ocean sunfish evolved to be. Their odd shape develops because their back fin never grows. Rather than expanding outward like a typical fish, it folds inward, creating a rounded rudder known as a clavus.
When they’re not impersonating sharks, ocean sunfish are lying flat on the surface of the sea, basking in the sunlight (hence the name).
But perhaps the most interesting thing about the mola mola is that they lack a swim bladder. This gas-filled organ is what allows most bony fish to maintain buoyancy. As a result, it was long thought that they simply floated wherever the sea pulled them.
Eventually, however, scientists observed that they do swim! Sure, they only go about 2 mph, but they’re perfectly capable of going against the current.
The only problem with moving this slowly is that it allows a wide variety of parasites to hop aboard. This is great news for seabirds, though, which pick the parasites off basking ocean sunfish.
“This is a mutually beneficial relationship—the birds get food, the mola gets cleaned,” Stock explained. “But sometimes their eyeballs are accidentally picked at … an unfortunate consequence for letting gulls eat your parasites at times!”