You can't vaccinate an octopus

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.

That's a problem if you're trying to raise a bunch of invertebrates in close quarters (as per a farm) because you can't immunize them against pathogens that could easily spread from one octopus to another. As a random biological tidbit, though, it's just damned fascinating. Check out this doctoral thesis for more information on how the octopus immune system does work. You should also read this story that looks at the evolution of the adaptive immune system and asks a key question — does having immune "memory" really make us that much better off than the animals that don't have it?

Image: Octopus, a Creative Commons Attribution Share-Alike (2.0) image from alicecai's photostream

10,000 baby octopuses, 80,000 arms, 1 night to remember

An octopus' life is short — two years is a pretty common lifespan — and heavily focused on reproduction. They only get one shot at carrying on the genetic lineage and die soon after breeding. Babies are born not by the two, or tens, or even hundreds. Instead, tens of thousands of octopus siblings enter the world all at once — tiny, translucent hatchlings that ride the waves and try not to die more quickly than they already must.

This footage of an brood of giant Pacific octopuses hatching was filmed by divers in Puget Sound just a couple of weeks ago.

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When the octopus says, "ouch"

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.

The unfortunate, awkward world of octopus sex

As if it's not bad enough that there's always a risk of any social interaction turning into cannibalism, the sex lives of octopuses are further complicated by the fact that both males and females die not too long after the first time they get laid. Males only survive a few months. Females stick around long enough for their eggs to hatch, and then die soon after.

And then, of course, there's the indignity of the local aquarium scheduling your mating for Valentine's Day, in front of a crowd, and putting a video of the whole thing up on the Internet.

Sorry, octopuses.

Read more about octopus reproduction in this piece by Katherine Harmon at The Octopus Chronicles.