I never see comments about the Narrow-Headed Garter of the mountain streams of Arizona and New Mexico. I live in Arizona, and I have seen these remarkable animals many times in their native haunts. They will crawl along the bottom of a cold mountain stream like other snakes crawl across the ground. The Narrow-Heads are looking for fish, and probably tadpoles. The snakes look just like water snakes, and there have been one or two attempts to revise them into Nerodia, but revisionist research has so far left them in Thamnophis.
Narrow-Heads aren't all that much to look at, unless your favorite colors are drab greenish-brown, but they are fascinating herps. They inhabit mid-to-high elevation streams that flow off the Mogollon Rim in Arizona, New Mexico and northern Mexico, and are found nowhere else--a southwestern endemic.
I have collected gravid females on a few occasions, and raised the babies to adulthood. In captivity, these primarily piscivorous snakes can be conveniently raised on a diet of bait minnows. Watching them hunt, it becomes clear why they have such narrow heads. I set the snakes up in terraria with a transparent water tank I could see through, so I could watch the snakes feed, and would put a few dozen minnows in when feeding day came. The snakes learned soon enough what the splashing of the fish meant as they were dropped into the basin, and would come quickly to the tank. The snakes put their heads into the water, and when they struck at the fish, their narrow heads cut through the water like a lance. A diet of fish is less sustaining than one of rodents, and my Narrow-Heads would go through a lot of minnows in a week--about a dozen or so apiece per feeding, and that about twice a week.
I have also seen Narrow-Heads many times in the wild, often in beautiful places like Oak Creek Canyon, and other trout streams in central Arizona's highlands. Once, while I was trout fishing in a pool, a fine male Narrow-Head crawled completely across the entire pool as I fished, seemingly undisturbed by my occasional catch. He didn't eat anything that I saw, but the pool's supply of native minnows had been pretty well cleaned out by the trout, so maybe that's why. There are plenty of minnows in those streams, though, and tadpoles of the Canyon Treefrog in season, plus the treefrogs themselves, so I expect my Narrow-Head didn't go hungry for long.
In Arizona, Narrow-Headed Garters are reasonably abundant in their range, although I think I remember hearing they are a species of concern in New Mexico, but in Arizona, there are no special management issues regarding them.
They are one of my favorite garters, with their unique adaptations to their special habitat. I'll post a pic sometime.
