Volunteer Kyler Morse holds one of the rare “axolotl” salamanders found in two of the Axolotl Lakes near Dillon.
Photo by Paul Hutchinson
Notice the gills and fin-like tails on these axolotl salamanders, juvenile characteristics carried into adult salamanders.
Photo by Paul Hutchinson
On the north slope of Montana’s Gravelly Mountains, surrounded by sub alpine meadows and timbered slopes, are the scenic Axolotl Lakes. The unusual name comes from an unusual species that inhabits the area: the neotonic (meaning “retention of juvenile traits”) form of the tiger salamander (Ambystoma tigrinum), commonly called “axolotl.”
While not a true axolotl - that distinction is reserved for a distantly related species (Ambystoma mexicanum) that occurs only in Lake Xochimilco in central Mexico -- Dillon’s axolotls exhibit nearly all the traits that make the true axolotl famous. Traits such as a fully aquatic lifestyle, retention of gills into sexual maturity, limb regeneration, and a finlike tail. The major difference between a true axolotl and our axolotl is that ours will readily morph into a terrestrial tiger salamander if its environmental conditions improve. However, it is extremely rare to find the Mexican species in the wild in other than the neotonic form.
The name axolotl comes from the Aztec language. One of the most popular translations of the name connects the axolotl to the god of deformations and death, Xolotl. The most commonly accepted translation is "water-dog" (from "atl" for water, and "xolotl," which can also mean dog).
The axolotls found in the Axolotl Lakes are actually the neotonic form of the blotched tiger salamander (Ambystoma tigrinum melanostictum). These creatures can reach 12 inches at full growth, with smaller 6 to 10-inch specimens most common. Within some populations are two distinct foraging lifestyles. The most common form feeds on insect larvae and small crustaceans such as scuds. The second has a much more sinister side in its feeding preferences. This form is cannibalistic -- a large percentage of its diet consists of its brethren. They are facilitated in this pursuit with a larger head and a mouth full of sharp teeth.
Not much is known about axolotls in Montana or elsewhere. It’s not known how long they can survive in the wild, but some from the Mexican species have been known to live for 20 years and more in captivity.
Why don’t these unusual creatures turn into adults? There are several conditions including high altitude, cold water temperature, lack of predation in the water, dry conditions outside the water, and hormones.
During the summer of 2007, fisheries biologist Paul Hutchinson and BLM volunteer Kyler Morse conducted an axolotl survey in the Axolotl Lakes chain to determine their distribution. During three days of survey, axolotls were found in only two lakes. Several dozen were caught and measured, with several individuals measuring over 10 inches. Larger axolotls seen but not captured were estimated to exceed 11 inches.
Historically, axolotls may have occurred in all of the natural lakes in the axolotl area. Today they are only found in two. Introductions of trout into several of the lakes around the turn of the century likely wiped out other populations.