“Sea serpents” aren’t just the stuff of legend; in fact, they’re quite common. Evolving a long, snake-like body is a popular strategy among many aquatic animals. Although the Vancouver Aquarium isn’t home to any true sea snakes (scaly reptiles that spend time in saltwater but breathe air), lots of snake-like fishes can be found slithering in our galleries.
A snake-like body is the perfect shape for hiding in caves and ambushing predators, and many fishes from different groups have evolved this strategy, including eels and “imposter” eels. Wolf eels, for example, are a common snake-like fish found in the Pacific Northwest. Their long body shape resembles that of an eel, but their closer relatives in the wolffish family have more typical fish bodies. Other eel “imposters” from B.C. waters include gunnels, pricklebacks, and wrymouths.
South American rainforests are home to another “eel imposter” the electric eel. While these animals really do produce electricity, they’re actually part of the knifefish group. Many kinds of knifefish have electricity-producing organs that can help them to hunt and navigate in muddy habitats. Electric eels are the largest members of this family, and having extra-long bodies allows them to store and produce more electricity than their smaller relatives.
A few “true eels” (members of the order Anguiliformes) can be found hiding around the Aquarium. Perhaps best known for their appearance in Disney’s The Little Mermaid, moray eels are tricky to spot in person. In spite of their fearsome faces, moray eels are quite shy; like wolf eels they spend most of their time in caves. A colourful zebra moray eel can be found in the shark habitat – if you’re lucky, you’ll see part of its striped body hiding among the rocks. You have to be very, very lucky to see this reclusive animal come out of its den. However, the new Sea Monsters Revealed: The Exhibition allows visitors a guaranteed look at a moray eel anatomy. A one metre long specimen greets visitors near the entrance of the exhibit.
Not all true eels have a fearsome appearance. Garden eels are small, colourful animals and are found near the seahorses in the Tropic Zone gallery. Unlike most eels, they are able to build their own caves, burrowing in the sand and exposing only part of their bodies. Since garden eels eat zooplankton (tiny animals that drift in the water), they can wait for food to come to them. If a danger approaches they can quickly dip back into their custom-made hiding place.
True eels and “eel imposters” look similar but are not necessarily closely related. Scientists use the term “convergent evolution” to describe what happens when two distantly related species develop similar appearances or behaviours. The serpentine body seems to be a popular one in the animal kingdom: outside of fishes, worms, axolotls, legless lizards, and snakes also share this shape. Keep your eye out for all kinds of serpentine sea creatures on your next visit to the Vancouver Aquarium.
Blog post by Derek A. Jang, interpreter at the Vancouver Aquarium Marine Science Centre.