Dr. Chris J. Law

So I just started building that phylogenetic tree and then just learning a bunch of natural history by reading about this group.

I at first didn't even know that weasels were related to otters.

So I learned more about weasels and kind of went down this rabbit hole to want to study why they so elongate.

The idea is that it came around 15 or so million years ago.

That's during the mid-Masin climate transition when temperatures drastically decreased and this expansion of grasslands occurred, which then led to the diversification of rodents.

So then this body elongation is hypothesized to have allowed those weasel-like creatures to go underground to chase all those rodents in these tight crevices and whatnot.

Yeah.

So that's the idea behind their kind of artificial selection, right?

Where people really are trying to breed these elongate looking dogs so they can go in these tight crevices or burrows to try to get those rodents during hunting.

That is a fascinating question.

So if you think of snakes or eels, they become more elongate by just simply adding more vertebrae, which makes sense, right?

But then with mammals, we're actually constrained to the number of vertebrae that we have.

So

In carnivorans, which are like dogs, bears, cats, they have about 20 thoracic lumbar vertebrae, and that number rarely, rarely changes.

So it can't become elongate by just adding additional vertebrae.

They have to actually evolve relatively longer vertebrae.

Yeah, exactly.

So they have the exact same number of vertebrae.

It's just some of the breeds might have relatively longer ones, although no one I don't think anybody has really looked into that.

So it'd be really interesting to see the skeletal elements of what actually contributes to those different body plans in these different breeds.