My first first-author paper came out last month, so I'm going to talk about it here. We were able to test cling performance in 20 species of plethodontid salamanders, see what angles they could cling to, and measure how much of their body they use to attach. #clingingsalamanders

Here's the link to the paper, if that was enough to pique your interest: https://jeb.biologists.org/content/223/17/jeb211706
If not, I'll put the TL;DR version here (below). (This photo by @FuncMorph)

The first thing we found was that salamanders are really, really good at clinging to smooth surfaces. Of 20 species, at 15 of them had at least some adult individuals capable of clinging to smooth acrylic upside down. #clingingsalamanders

Including this heckin' chonker, a 14 g Bolitoglossa franklini #clingingsalamanders

A few species were incredibly rubbish at clinging, despite being a pretty reasonable size, like this Ensatina eschscholtzii, who seems to have missed the memo to try hard.

We measured how much contact area species used when clinging and how that varied with size. We had expected to see the relationship between mass and surface area that would lead large salamanders to cling poorly, especially given the size range in these guys. #clingingsalamanders

We used a cool (and cheap) method (adapted from Betts et al 1980) where edge-mounted LEDs shoot light into the plane of an acrylic sheet, and areas of the body in intimate contact with the surface are illuminated, making them easy to measure in ImageJ. #clingingsalamanders

Even though my rough setup didn't collect contact area data continuously, we were able to get snapshots of how much area salamanders used to cling at different angles, and compare that with body mass. #clingingsalamanders

The most interesting points on that line turned out to be Ensatina escholtzii, a terrestrial salamander, and Desmognathus quadramaculatus. Even though the tested individuals were of similar mass, Dq wildly outperformed Ee. #clingingsalamanders

Most poor-performing clingers had less contact area per unit body mass, as you'd expect, but not Dq. We speculate that their ventrally flatten profile for hanging out in streams, and their sprawling posture, gives them a little extra contact area.

Most salamanders aren't using 100% of their available ventral body surface to cling, even during max performances. #clingingsalamanders

In the case of Ensatina, they use so little of their available ventral surface that an anesthetized Ensatina clings better than a conscious one. #clingingsalamanders

So do salamanders notice that clinging is becoming more challenging with increasing angle and crouch to put more of their body in contact with the surface so they cling better? Not really. #clingingsalamanders

The last tantalizing clue to salamander clinging from this study were species that clung better or worse than expected despite their body mass and surface area. Two key players were Bolitoglossa franklini and Ambystoma gracile. #clingingsalamanders

Bolitoglossa clings significantly better than the nearest species in size, Plethodon metacalfi, despite no significant differences in contact area. Ambystoma gracile clings significantly worse than A. maculatum, despite using significantly more contact area. #clingingsalamanders

Does this mean some salamanders are stickier than others? Or some salamander way less sticky? Questions remain! #clingingsalamanders