Above: Arizona tiger salamander (Ambystoma mavortium nebulosum). Photo by Eric Phillips

Murray State University biology professor Howard Whiteman, PhD, has studied the same population of Arizona tiger salamanders (Ambystoma mavortium nebulosum) in the Mexican Cut Preserve north of Gothic since 1990. It’s likely the longest continuous study of this species anywhere, he says. So it says something that he still describes a moment a few years back as a genuine “eureka.” 

Equipped with a simple black box, filtered sunglasses, and an iPhone camera, Whiteman and his research team switched on a specialized flashlight, and a salamander that looked perfectly ordinary in daylight suddenly had a glowing green wash along its back and a stripe near its tail. They knew other salamanders exhibited biofluorescence, but this was the first time they’d tested and seen it at the Cut. “In the same way that we don’t appreciate the ultraviolet light that bees and hummingbirds see, or the way we didn’t appreciate the echolocation bats were using, I think it’s the same kind of thing here,” Whiteman says. “It’s just a new way of sensing the world. We know their retinas are attuned to that wavelength. They’re seeing the world differently than we do.” 

Whether biofluorescence plays a role in finding mates, sizing up a rival, or something else entirely is an open question that Whiteman’s team is pursuing. Just last year, Whiteman’s Murray State student Julianne Chairez figured out that the intensity is environmentally sensitive — it changes depending on the light levels under which the salamanders were raised. This year, working with Georgia Tech undergraduate Katie Stone at RMBL, she began testing whether raising them at different densities has an impact.

Understanding why these salamanders fluoresce is a relatively recent and specific pursuit. Understanding what’s “normal” at the Cut has been a much longer-term and broader effort, tracing back to when RMBL researchers Robert and Scottie Willey first came upon this bowl-shaped basin in 1958 and, recognizing its scientific value, began a years-long effort to protect it. (Today, the preserve is owned by The Nature Conservancy and managed by RMBL.)

The baseline created by watching the same ponds year after year has enabled Whiteman and his students to see evidence of changing behavior in recent years. They watched the salamanders start breeding in the Cut’s higher-elevation ponds (the Upper Cut) for the first time in 2014 or 2015; last year, the salamanders bred in multiple ponds at the Upper Cut, suggesting it’s happening more frequently, he says. This year, for the first time on record, a larva survived two full winters at the Upper Cut before finally metamorphosing. “The realization that climate is more important to their life history than I thought — that was a big one,” Whiteman says as he recounts his top “eureka” moments, many of which he recognized only because he’s watched this population for more than three decades. 

To measure the impact of a changing climate on salamanders more precisely, Whiteman and Kelsey Reider, PhD, an assistant professor at James Madison University who collaborates with Whiteman on salamander physiology, have spent the last several years implanting the animals (some of which can be a foot long and over 30 years old) with small temperature data loggers that record body temperature day and night, through an entire winter under the ice. “Even if we know pond temperatures are shifting,” Reider says, “we don’t actually know what that really means for the animals experiencing them.” As far as she knows, nobody had directly tracked body temperature this way in salamanders before this study, which means the data coming out of this year’s historically low snowpack may be some of the most telling yet. 

The salamanders aren’t the only animals at the Cut whose behavior is diverging from their regular patterns. Hamish Greig, PhD, and Amanda Klemmer, PhD, married aquatic ecologists at the University of Maine, have sampled the Cut’s caddisflies using the same protocol for over two decades, often working side by side and in collaboration with Whiteman’s team. During that time, they’ve watched a formerly lower-elevation caddisfly species move upslope and establish itself here. Greig traces the shift directly to low-snowpack years: In 2021, after two of them in a row, far more individuals than usual completed their full life cycle at the Cut, and the population boomed. Because the species overwinters as a larva instead of sitting out the cold as an egg, its arrival means a surge of large, calorie-rich prey now shows up in these ponds every fall. That’s just when the salamanders need to bulk up before winter. The paedomorphs — the sexually mature, overgrown larvae that stay in the ponds rather than transitioning to terrestrial life — have been “nice and fat and happy” as a result, Greig says. 

Greig sees that kind of finding as the whole point of working somewhere like Mexican Cut. Most of what happens here is basic science, not applied science, he says, and the second depends entirely on the first: “You can’t know why a car is broken, or how to fix it, until you understand how it runs in the first place.” The same logic scales up, he says: Understand an alpine valley like this one well enough, and you start to understand the network of headwaters that feeds the Colorado River, with the aquatic invertebrates, the salamanders, and the wetland plants all part of the same water system. 

Whiteman and Reider will spend the next several years watching how the salamanders fare in the wake of this year’s low snowpack, and what their body-temperature data reveal about it. Meanwhile, Greig and Klemmer will be watching whether the newly arrived caddisfly species raises predation pressure on the species already living here by giving the paedomorphs an edge. “That’s something we want to test in the next few years,” Klemmer says. Some questions get answered in a season. These take longer. And maybe, somewhere along the way, somebody gets to say, “Eureka!” 

Help make the next “eureka” possible. When you join our family of Explorers, you both support this long-term research and get a behind-the-scenes look at RMBL science in the field — including at Mexican Cut.