Anemone eats bird, and other surprising animal meals

There’s an old saying in journalism: If a dog bites a man, that’s not news. Man bites dog: That’s news.

So how about a sea anemone that chows down on a bird? Researchers have reported finding a giant green anemone chowing down on a young cormorant. The photo of the event looks something like a purple Thanksgiving turkey being attacked by a neon-green hairbrush.

The picture is surprising because, as researcher Lisa Guy of the University of Washington in Seattle told Deep Sea News, it’s an “example of an apex predator being consumed by an animal that doesn’t seem to really do anything.”

Most people think of sea anemones as pretty floral-looking blobs, and they are, but they’re also carnivorous predators. The giant green anemone (Anthopleura xanthogrammica) regularly eats small fish, crustaceans and mussels. And now it looks as though it may not be terribly unusual for well-placed anemones to vacuum up bird chicks that get knocked from their nests into the water.

Lisa Habecker of the Haystack Rock Awareness Program spotted the bird-eating anemone at Haystack Rock in Cannon Beach, Ore. She had seen a bird meet a similar fate at Haystack Rock in 2003 when a young western gull fell directly onto a large anemone that swallowed the chick whole, leaving just the feet sticking out.

On the morning of July 24, 2013, a group of onlookers directed Habecker to a tidal pool where she saw that history had repeated itself. This time it was a cormorant sticking out of a green anemone. “I knew this was going to be the ‘center of attention’ for the day,” Habecker says. She took underwater photos and documented the find with Guy and a colleague in a paper to be published in an upcoming issue of Marine Ornithology.

The cormorant was still in rigor mortis, suggesting it had died within the previous two days. “It is unknown whether the chick was alive or dead when engulfed by the anemone. It is possible that a predator such as a bald eagle Haliaeetus leucocephalus dropped this chick or that it was knocked from the nest,” the team writes. 

It’s not clear how long it takes an anemone to digest an entire bird; the recent example was soon buried by swishing sands in the tide pool where it was discovered. But there’s no reason to think an anemone couldn’t digest a bird eventually. Anemones eat by using harpoonlike stinging cells on their tentacles to hold prey in place while paralyzing it, then pulling the food into the mouth opening at the center of the anemone. The little harpoons can keep stinging the prey even after the anemone has swallowed it, injecting digestive enzymes to break down the unlucky fish or whatever else wandered too close. The anemone absorbs nutrients from the digested goo and expels anything inedible, such as bones or shells.

Anemones are far from the only creatures that can take on unexpected prey. Here are just a few more examples of animals eating bigger or better-armed prey, or just snagging their dinners in hair-raising ways.

These animals don’t all live in the same place, but if you could get them together you might end up with a food chain not found in any textbook.

1. Anemone eats bird.  This underwater video shows the giant green anemone eating a bird at Haystack Rock on the Oregon coast:

2. Bird eats bat. The birds known as great tits (Parus major) are cute little yellow birdies that have been described as predators that “search for, capture, kill and eat hibernating bats.” Researchers in Germany and Hungary reported in 2010 that the birds systematically search for the bats and peck them apart, consuming their flesh, brains and organs.

3. Bat eats crustacean. The fishing bats of Belize (Noctilio leporinus) use echolocation to detect ripples on the water to find fish, frogs and aquatic crustaceans. A bat swoops down and drags its back claws through the water to snag its prey.

4. Crustacean eats fish. The marine louse Cymothoa exiguais a parasite that latches in a fish’s mouth and eats its tongue, then takes the tongue’s place as a surrogate tongue. (Hey, at least they’re being helpful.) What happens next is not as nice: A male louse turns into a female and breeds inside the fish’s mouth.

5. Fish eats moth. No problem. Plenty of fish can jump from the water to catch flying prey. Many aquarium owners have been surprised to see their fish leap up to catch the fluttering insects.

6. Moth eats you. Vampire moths (Calyptra thalictri) in Siberia have to rock back and forth to get their big thick proboscis through human skin, but they’re game if you’ll hold still long enough. The blood-suckers may have evolved from fruit-eating species, and it’s possible that male moths pass the blood to females as a salty gift during mating. 

So there you have it: anemones to humans in six degrees of degustation.

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