MOS: Deep Sea Gigantism

Fuck it. Let’s make some nightmares.

Today’s Moment of Science… sea monsters.

Evolution sometimes gets trimmed down to “the fittest survives, so I shouldn’t skip leg day.” But with evolution, ‘fittest’ doesn’t mean the strongest or biggest or most poisonous. In many ways, it means the critter that best fits their environment. Australia has every big, strong, poisonous, bitey, scratchy, platypussy critter on this fair Earth. They’ve gone to war with cats, bunnies, and goddamn mice because this planet is determined not to make sense.

Then there’s the depths of the ocean. 

A place so dark that Anish Kapoor is buying the rights to it, nearly goddamn everything about it remained an enigma until recent history. Could anything even survive in a place where humans hadn’t been able to venture for most of our existence? 

Handily.  Some of them are adorable little floofs and blebs with bioluminescent features. You just want to boop their snoots and send them on their way.

Then there’s the phenomenon of deep sea gigantism. You’re welcome or I’m sorry.

You find a variety of critters of unusual size at the depths of the ocean, many of them crustaceans or cephalopods. There are also some larger than life eels and jellyfishes, because we needed diverse ways to haunt your dreams.

So as we peer into this abyss together, the mind reels wondering… fucking why?

As you get closer to the sea floor, a few things happen, one being that everyone is goddamn cold and hungry. Buried under a few zillion gallons of water, pollution, and orca piss, this is a place where no light has warmed a soul or photosynthesized a calorie since two supercontinents ago. Kleiber’s Rule (named for biologist Max Kleiber) proposes that larger species tend to be more metabolically efficient. It could be months before a good sized meal plummets down sometimes, a creature with a hummingbird’s metabolism isn’t going to make it.

Bergmann’s Rule suggests that larger animals within a taxonomic clade tend to live in colder temperatures. It’s more like Bergmann’s guideline, but we see this happening with several groups in the animal kingdom. Additionally, oxygen saturation in the ocean rises as pressure increases, and it’s been proposed that gigantism is an adaptation to this.

It’s not that there aren’t large animals elsewhere in the ocean or that there aren’t small animals on the ocean floor. It’s that these giants are alarmingly bigger than their cousins. The deep water sea spider can grow up to 20 inches. A lot of its closest evolutionary cousins are just a couple of millimeters. The giant isopod looks like a mad scientist decided they wanted a bug instead of a pet dog and, lo, a twenty inch yikes. Typically isopods are about two inches. After the giant squid stopped being a myth, the largest one we’ve met is 43 feet long. So far.

I’m not sure if any of this has been nightmare fuel, but then, I didn’t talk about the jellyfish yet.

We’re talking about those tomorrow.

This has been your Moment of Science, reminding you that there are advantages to not being the biggest fish.

To get the Moment of Science in your inbox every weekday with tales of NASA funded dolphin handjobs, rocket scientist orgies, and fucking… Australia… head to patreon.com/scibabe.

Liked it? Learned something? Made you think? Take a second to support SciBabe on Patreon!