Today’s diversity biology lab was AWESOME! I knew it would be fun – we looked at Echinoderms, which are just super cool, and we had a bunch of live starfish and sea urchins for them to examine under the scopes. So, that part was expectedly great – we fed the urchins bits of nori and watched them eat, and we looked at the starfishes’ tube feet, and some of the students took selfies with the critters. Very cool.

Then, when we were wrapping up to go back to the classroom (the tanks with the live creatures are in a different room), something totally amazing happened: one of the rock crabs decided to eat an urchin, while we were watching. I really didn’t expect this – the urchins and crabs have been living in that tank together for weeks now, and I hadn’t seen any sign of predation (well, not by the crabs; one of the starfish ate a chiton on Tuesday). I guess the rock crab was hungry. 😀

We watched while the crab grabbed the urchin and began to dismantle it with it’s two large claws. It literally cut the urchin apart, and scooped out its innards and stuffed them into its mouth. We could hear the endoskeleton crack, and there were guts floating around in the water. I’m honestly not even sure at what point the urchin stopped being alive – throughout all of this, its tube feet kept moving around, as though it were trying to escape. That part was a bit sad, but it was a good example of nature in action.

This was one of the most interesting thing I’ve seen on campus in all the years I’ve been at this school. It was really, really cool to watch, and my students were SO EXCITED!

That’s still not the end of the story, though . . .

You know how once in a while, there is a moment when you see a golden opportunity, and you take it? And it creates a rare moment of such great beauty, it’s like the sun coming out from behind the clouds on a rainy day? Today, I had one of those moments.

As we were watching the rock crab devour the urchin, someone asked about the other crab in the tank – a kelp crab – whether or not it might try and fight the rock crab for part of the urchin.

Using my best, most serious teacher voice, I said, “Do you know why the rock crab isn’t sharing its kill with the kelp crab?”

My students turned to me with expectant faces, waiting for me to drop some science knowledge on them. A few of them threw out guesses: “Because it’s a different species?” ~ “The rock crab is territorial?” ~ “Because the kelp crab doesn’t like to eat urchins?”

And I said:

“No. It’s because the rock crab is shellfish.“

*drops the mic*

AND THEY LAUGHED! THEY LAUGHED REALLY HARD! GENUINE LAUGHTER!

This was almost certainly the most sublime joke-telling moment in my whole life. Never again could that joke be so perfect, so appropriate, so hilarious. THEY LAUGHED and I did a victory dance, and it was so amazing.

So, yeah. Lab today was awesome.