The Lobster and the Hare

Sea Hares’ Sticky Defence Uncovered

Besides the interesting biology in the article, I really loved the picture and video featured in this article. The photo is really stunning and it’s great to see the sea hare’s defense in real time. I don’t think this type of hare is going to beat any tortoises anytime soon. Although, that face off might actually turn into quite a race.  However, just like how the torpid tortoise has a protective shell, sea hares have some defenses of their own to make up for their lack of speed. Not only do sea hares have defensive chemicals in their skin and skin mucus, they also possess the ability to release a purple ink and a white substance called opaline. Until recently, the role opaline played in a sea hare’s escape plan was unknown. Researchers now believe the sticky substance can function as a “sensory inactivation” agent by coating a predator’s antennae, thereby inhibiting the predator’s chemical senses or smell. Scientists believe the newly sensory-deprived predators lose their appetite, and ridding themselves of the sticky coating takes priority over a tasty snack. Ideally, the sea hare’s inky ooze buys the animal enough time to wiggle away. Scientists showed that spiny lobsters that had their antennae coated with sea hare gland extract had significantly reduced “electrical activity in the chemosensory and motor neurons in their antennules.” Researchers were excited about the results because, “It is the first demonstration involving not only the chemical senses, but to our knowledge, any sensory system.” Because of the plethora of predators that seek this sea delicacy, it is especially important for sea hares to have multiple defenses. Some chemical defenses may not work on certain predators, so sea hares often need a plan B…or C…or D!

I also liked the “strange lives of sea hares” side blurb in the article. It says that sea hares are gastropod molluscs, meaning they have small, internal shells. Additionally, while the sea hare in the video was reasonably small compared to the lobster, some species of sea hare can grow to be 70cm (about 27.5 inches) in length! Hence, sea hares can use size, skin chemicals, mucus chemicals, internal shells (somewhat?), colored ink, and sensory-deceiving ink to elude predators. I think that’s some pretty amazing biology from something that just looks like a slow-moving blob!

Extra: From what I can find online, sea hares are a type of sea slug. Although not all sea slugs have this “inking” ability, many sea slugs have some incredibly beautiful “warning” coloration instead. I highly recommend perusing this website: 25 Most Colorful Sea Slugs on Earth

Sea Hare. Wiki Commons: Scott A-P Muzlie

Sea Hare. Wiki Commons: Scott A-P Muzlie


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