biomechanics and behavior of squeezing through small openings

this is nothing. it's incoherent as written and the thing it's trying to express isn't even true. hagfish have been evolving and speciating the whole time they've been on the planet, just like everything else that lives here. phylogenetic analysis indicates major divergences in hagfish lifestyles were occurring as recently as 58.8 million years ago. 300 million years is the age of the oldest identified stem hagfish fossil, Myxinikela. since then, hagfish have done things such as getting rid of complex eyes, which i think maybe doesn't qualify as remaining unchanged.

anyway watch this video and laugh at the use of the 'scary shaky cam of an approaching SCARY BEAST' film technique on... some hagfish swimming towards an already dead fish. vicious mob of humans eager to rend flesh! (shaky cam footage of humans standing in line at the grocery store)

(the video does show the hagfish entering the dead fish to feed but that's normal for scavengers. things would be worse if they weren't around to do this.)

(it also has a really good shot of a hagfish everting its tooth plates)

(honestly just turn the sound and subtitles off and look at the hagfish, the narration is terrible but the footage is remarkably good)

some things i like about it are: it is interested in hagfish as living organisms, primarily for the sake of learning about hagfish. it examines hagfish from both major genera (Eptatretus and Myxine). when the hagfish used in the experiment were placed in the tank they lived in while not being tested, they were observed to be particularly interested in exploring the corners of their tank. so the testing tank was designed to have a 'corner' with a gap, encouraging the gap-squeezing behavior the researchers wanted to see organically.

the last part is what makes it my favorite. there aren't very many studies focused on hagfish behavior and cognition. this is partially a result of the massive lack of knowledge about these animals but also feels to me like a consequence of the way many people think about them. the primitive, basal hagfish, a lower, devolved organism. probably not much going on in there.

so the choice to look at how the hagfish behaved in the holding tank and shape the experiment to that behavior is very exciting! additionally, there are a number of very specific observations made about the hagfish ability to squeeze through small openings (both species were successful at getting through gaps that were half of their initial body width) and how several unique aspects of their biology influence their ability to do this that i think are really cool.

^ peak performance

source:

hagfish research simulator.