Salamanders are probably my favorite organisms on the planet. I know that I posted something this summer about how bombardier beetles are the best organisms on the planet, but I can pick favorites based on other qualities, and salamanders have plenty of those. For example, some mole salamanders (in the Ambystoma jeffersonianum complex) reproduce through a process known as gynogenesis. These entirely female lineages clone themselves in order to produce offspring — but they cannot reproduce without mating. Instead, they mate with males from closely related species, essentially stealing their sperm, without passing on paternal genes. (If anyone wants me to talk about this at length, I totally can, because it’s awesome.) Other salamanders are known for their remarkable ability to completely regenerate limbs that they have lost (axolotls, Ambystoma mexicanum are the model organism in which this has been most extensively studied, but the phenomenon of limb regeneration is well known from many, many salamander species) and their incredible longevity (olms in the genus Proteus can live to well over seventy years). The largest amphibian in the world is a salamander —Andrias davidianus can reach over four feet in length and weigh sixty pounds.
Basically, frogs are boring?
Anyway, the reason that I’ve been thinking about salamanders is that I’m in North Carolina for the annual Society of Vertebrate Paleontology meeting, and because this state has the world’s greatest diversity of salamander species, I took a few days before the conference to go herping with friends. The salamander catch wasn’t great — it’s a little late and a little dry — but poor salamandering in North Carolina is better than excellent salamandering almost anywhere else in the world, so I’m not really complaining.
Most people probably go to the Great Smoky Mountains to look at things like bears and foliage, but they are wrong — bears are everywhere, as are trees. If you take the time to flip over a few logs, though, you will almost certainly find one of these guys — and they occur nowhere else in the world. Red-cheeked salamanders are mildly toxic; they secrete a nasty mucus when disturbed, and the red color on their cheeks is generally thought to be warning coloration deterring potential predators.
The imitator salamander, Desmognathus imitator shares its range with the red-cheek, and takes advantage of the other salamander’s chemical defenses by mimicking its coloration in order to deter potential predators. This is a biological strategy known as Batesian mimicry, in which a harmless species mimics a toxic or otherwise dangerous one in order to improve its own odds of survival.