Fishing is all about deception – convincing a gullible fish that the lure is really a tasty treat. That’s the case whether the angler is a human or another fish an anglerfish. The anglerfish is probably one of the ugliest creatures on the planet, but it’s also one of the most interesting. In some of its more than 200 species, for example, the male becomes a small parasite. It attaches itself to a female, then loses its vision and even its ability to move. It feeds off the female, and its only job is to fertilize her eggs.
Anglerfish are ugly but interesting. Credit: National Oceanic and Atmospheric Administration/ David ShaleAnd then there’s the trait that gives the fish its name. In many female anglerfish, a long spine – an extension of the front of the dorsal fin – hangs over the fish’s head. The spine is tipped with a small sac, the esca. The fish wiggles this structure around in front of its head. Other fish think it’s a small creature swimming on its own, so they take the bait – and quickly become the anglerfish’s prey.
The anglerfish’s mouth is filled with rows of big, sharp teeth. When the prey touches the esca, the jaws snap shut, trapping a meal. The anglerfish can stretch its jaws and stomach so wide that it can eat a fish up to twice its own size. Anglerfish in the dark of the deep ocean have one other bit of deception. The esca is filled with millions of bacteria that produce light – an effect known as bioluminescence. Since many of the ocean’s light-producing creatures are edible, the light attracts attention – luring prey into the jaws of this deep-sea angler.
