Call
me Bob Short for bobtail squid. (Did I mention that I'm a 3-4 centimeter cephalopod (defined)?)
The bobtail squid, Euprymna scolopes, courtesy of Margaret McFall-Ngai.
Anyway, I hang out in the shallow waters around Hawaii. Before you start shedding crocodile tears (defined) in sympathy -- let's just say that somebody's got to live in the sunny ocean around the reefs. Anyway, let me tell you my problem: Even though I have 10 legs, I don't have spines, poisons, or any other good way to defend myself.
So I spend my days burrowing into the sand, trying to keep out of mischief. Still, a fellow's got to eat, don'tcha know, so I cruise around at night, looking to grab a bite. That's the snag: There are all sorts of other predators out there with calamari on their minds.
Since they evolved before flashlights (not to mention rechargeable batteries), they had to improvise. Even their tiny squid brains could figure out that predators were seeing them from below, as tasty dark blobs against the brighter ocean surface. So (at least, this is how my great-aunt Tentacla tells it) they press-ganged billions of luminescent bacteria into making light for them. The idea was to make my kind just as bright as the ocean surface -- and hence invisible.
My relatives fed the bacteria, and gave them a place to live in two specialized light-emitting organs called photophores. I guess they decided to make these photophores into backwards eyes. Anyway, the photophores use a reflective membrane to shine all the light down, toward the hungry predators. They use a diaphragm to control how bright they are, and have even a lens to spread the light around the body.
My folks even figured out how to make the bacteria light up when they were needed -- all in return for room and board. It's a biological deal they call "symbiosis" or "mutualism." Sometimes I think people could use to learn from this kind of cooperative spirit.
But that's enough thinking for one day. My squid brain is bushed. But before I burrow into the sand for another long tropical day, permit me to introduce somebody who considers me almost as fascinating as I do.
Light
before flashlights
A long time ago, my ancestors came up with a nifty way to protect themselves against big teeth lookin' for a snack: stealth.
