The Western Green Ratsnake (Senticolis triapsis intermedia)

The western green ratsnake (Senticols triapsis intermedia) is an extremely secretive, and therefore difficult to find, Arizona native. Nonetheless, this beautiful and different species is popular in herpetoculture. The common name is somewhat of a misnomer, the western green ratsnake is really only green over its range in Arizona and Chiapas, Mexico (Staszko and Walls, 1994). It is a relativly long, slender snake measuring 25-60 inches (60-150 cm) with an olive green, grey-green, or green dorsum and an off-white or cream ventral. This snake has a very limited range in extreme southeastern Arizona and prefers mountain woodland, thornscrub, and chaparral habitats. Like the rosy boa, this species is attracted to a permanent water source (Stebbins, 1985). The western green ratsnake will climb and can often be found during the day in trees or shurbs. At night, this species returns to hiding areas in boulder piles. The best time to find this snake, like the rosy boa, is during the spring. Because this species often spends the daytime in vegetation, the best time to look is during the early morning and twilight hours when the animals are moving to and from their nighttime retreats. The cryptic coloration of this species makes it almost impossible to see among the leaves of chaparral plant species. Juveniles have a brown pattern much like a corn snake, which fades into uniform green as the animals mature.

Captive Care

This species has been quoted as being "one of the most difficult ratsnakes" to keep in captivity (Staszko and Walls, 1994). Wild-caught animals of this species, are indeed, difficult captives. Wild western green ratsnakes are often heavily parasitized and easily stressed, both of which combine to make this species venerable to serious captive husbandry problems. Wild caught specimens are best kept by experienced herpetoculturists. Captive born offspring are a much better choice is one desires to keep this species. The thermal gradient for this species should be 65-70 degrees F (18-21 degrees C) on the cool end with a warm spot of 80-85 degrees F (26-29 degrees C). Like the rosy boa, this species must have hiding areas in the cage in order to fare well. Adult western green ratsnakes should be housed in enclosures no smaller than 3 x 2 x 2 ft (1 x .66 x .66 m). Larger caging is preferable, as this species does like to climb. Substrates may be newspaper, wood chips, paper towels, or substrate collected from the habitat.

Breeding

Breeding the western green ratsnake is very similar to breeding other North American ratsnakes. Males are distinguished by their proportionally longer and thicker tails, and by probing. Male western green ratsnakes will probe to a depth of 7-10 subcaudals whereas females will only probe to 3-5 (there are of course, variations, but almost all females probe below 7). This species should be hibernated at 50-55 degrees F (10-12.7 degrees C) for two to three months. After hibernation, feed the females heavily and look for the first post-hibernation shed. After the first post-hibernation shed, introduce the male. If the female is ovulating, copulation should take place within a few hours, many times, it occurs almost immediately. If copulation is not observed, remove the male and try again a few days later. Gestation runs anywhere from two to three months. As with other colubrids, the female will generally have a pre-egg laying shed one to two weeks before oviposition. Incubate the eggs in slightly moist vermiculite at 78-82 degrees F (25.5-27.7 degrees C). After 60 to 90 days, the eggs should hatch. The western green ratsnake is more rare in herpetoculture than the next Arizona native, the banded gecko (Coleonyx variegatus).