In a piece on octopus farming, Katherine Harmon mentions a fascinating fact — octopuses don't have an adaptive immune system, the handy-dandy network of different immune-response cells that allow us vertebrates to more easily fight off infections our bodies have encountered before.
Given that people are going around doing things like cutting off octopus limbs in order to understand their distributed neuron processing system, it's worth asking some questions about how octopuses perceive pain, as well. That's more complicated than you might think. As Katherine Harmon explains, it's likely that octopuses have some kind of awareness of when they're touching something unpleasant. But just how that works, and how similar it might be to the way we vertebrates understand "pain", is a big mystery.
This is the second story in a four-part, weekly series on taxonomy and speciation. It's meant to help you as you participate in Armchair Taxonomist — a challenge from the Encyclopedia of Life to bring scientific descriptions of animals, plants, and other living things out from behind paywalls and onto the Internet. Participants can earn cool prizes, so be sure to check it out!
On the sixth floor of New York's American Museum of Natural History — far away from the throngs of tourists and packs of schoolkids — there is a cold, white room, filled with white, metal cabinets.
The cabinets are full of dead things; leeches, sea anemones, lobsters ... any kind of invertebrate you can imagine. Even a giant squid. All of them have been carefully preserved. Each soaks in its own, luxuriant ethanol bath. Here they sit, some for a hundred years or more, waiting for scientists to pull them out into the light.
It's a bit like the final scene of Raiders of the Lost Ark, but for slimy, crawly, spineless things. There are collections like this all over the world, containing every species of animal, plant, and microscopic organism. Together, they serve as a record of Earth's biodiversity, a library of life. In them, you'll find more than just random specimens. Some of the individuals are special. Called "type specimens", they serve as ambassadors for their species, real-world models that define what each species is. For instance, the leech species Myxobdella maculata is both a group of leeches and exactly one leech — A leech that I got to meet on a behind-the-scenes tour with invertebrate curators Estefania Rodriguez and Mark Siddall.
Say you're a marine biologist and you want to study the little bitty creatures of the sea — shrimps and worms and things like that. How do you go about capturing them?
Why, with an underwater vacuum, of course.
At the PNAS First Look blog, David Harris writes that this "SCUBA-tank powered vacuum, called an “airlift,” inhales shrimp, sand fleas, marine worms, and 'things that would swim away if they had the chance.'"
How's this for an amusing case of photographic mis-identification? Call it "Dueling Disgustingness". Last week, New Scientist posted this lovely image of a blue-spotted sea urchin, taken by nature photographer David Fleetham.
New Scientist identified the photo as depicting said sea urchin in the process of expelling its own guts out of its mouth. Which, gross, but okay. That's reasonable. A surprising number of underwater animals eat in this manner, using the acids in their guts to dissolve prey before they actually slurp it up as a slurry.
But, at the Echinoblog, Smithsonian invertebrate zoology researcher Christopher Mah makes a compelling case against New Scientist's interpretation. That's not actually the sea urchin's mouth, says Mah. In fact, it's the opposite. That's a (rare) photo of a sea urchin taking a dump.
Mah has a lot of good photos that make his case quite well. You should check them out. Then, join me in contemplating this thought: If Mah is right, doesn't sea urchin poop look a lot like Dippin' Dots?
Warning: This video contains footage of an octopus hiding under a coconut shell that it has carried around just in case it needed to hide from something. Watching this footage may contradict your previous assumptions about animal tool use, and may be too adorable for some viewers.