Thamnophis eques insperatus (Conant, 2003); Lake Zacapu Garter Snake
Thamnophis eques insperatus, a subspecies of the Mexican Gartersnake, is very rare in most private garter snake collections.
This subspecies occurs only occurs in Laguna de Zacapu, Mexico. Thamnophis eques insperatus was described by Conant (2003) after finding one dead on the road specimen in the sixties of the previous century. It was not seen alive ever since and the article in wrote (Bol, 2012) may be the first description (and first pictures) of living specimens.
Length and size of Thamnophis eques insperatus
T.eques is a very large and heavily built gartersnake and Conant (2003) had set the new record for T.eques (obscurus) at 121,6 cm total length. Personally I have observed a Thamnophis eques insperatus of 122,8 cm total length (Bol,2012). Especially female Thamnophis eques can grow very large and heavy. In fact adult female T.eques are the largest gartersnakes I have ever seen.
The only garter snake that really grows to much larger size is Thamnophis gigas from California.
The new record for T.eques (scotti) is now set at 130,7 cm (Bol & Bruchmann, 2012).
Description of Thamnophis eques insperatus
Thamnophis eques insperatus, juveniles of a few days old, light and dark morph.
I have observed (Bol, 2012) the Lake Zacapu Garter Snakes in two different morphs: a lighter colored one with lots of yellow coloration and a dark phase that seems to lack all yellow colors.
However the series of snakes I observed is too small to make hard statements all the color morphs of this subspecies. Maybe T.e.insperatus is simply highly variable.
The dark morph lacks the dorsal stripe (when they are adult) but the bluish green lateral stripes on scale row 3 and partly 4 are relatively well defined. The dark (black) dorsal scales have a brown keel which creates a pattern of narrow stripes if examined closely. The centre of most dark dorsal scales is also often lighter colored (brown). This creates a beautiful mosaic.
The double row of large spots between the 3 stripes (although the dorsal stripe is often hardly visible) is often subdued but can become visible due to white coloration of the skin between the spots. Especially if the skin is stretched after eating a large prey.
The fluorescent nature of the shiny scales makes a description of coloration and pattern difficult.
In most of the light colored snakes all 3 stripes are clearly visible, especially in the juveniles. Also the double row of spots between the stripes is more prominent.
The ventral scales are bluish grey and bordered with black lines.
The underside of throat and tail are clearly different in coloration similar to some of the other subspecies of T.eques . The throat and labial scales are bright yellow in coloration and the underside of the tail can be slightly orange-pink in coloration.
The upper labial scales are also bright yellow with often black sutures. The yellow coloration also extends in the neck to form a somewhat yellow ring. In this way some snakes resemble the European Grass Snake (Natrix natrix).
The upper side of the head is usually dark or black.
The Lake Zacapu Gartersnake does very well in captivity. Due to its large size it is recommended to keep them in a terrarium with a minimum size (for one adult couple) of 100 x 50 x 50 cm, although a length of 150 cm would be more suitable. They do well in a dry and well ventilated cage with just a water bowl for swimming and drinking. The water bowl should be big enough for them to submerge in. Local temperatures in the terrarium should rise to 30 – 35 °C. T.e.insperatus are voracious feeders and relatively easy to keep. The snakes show themselves a lot basking on a branch under the lamp. Especially when the terrarium is not so warm and the snakes need to bask on the hottest spot to reach their optimal body temperatures.
A hibernation will not be absolutely necessary although it is expected that they will have a resting period in nature when they are less active. A cool period in the terrarium of 2 – 3 months will probably be sufficient to keep the snakes in good health and to stimulate breeding. Up to now I hardly give the snakes a hibernation. But the snakes are clearly less active in the coldest winter months; they bask less and often refuse to eat for several months. So do not worry when this happens.
During the winter months night temperatures in my snake room (and in the terrariums) drop at night to 8 – 12 °C. I keep my adult snakes in a completely dry terrarium with a water bowl. This species is also very suitable for a so-called “aqua-terrarium” with a lots of water and only a small (completely dry!) land part which is heated by a powerful lamp to 30 – 35 °C. In such a habitat terrarium the highly aquatic snakes will show more of their natural behavior.
The young are usually born in my terrariums in June, July or August.
Distribution and habitat of T.e.insperatus
Lake Zacapu, habitat of Thamnophis eques insperatus in November 2008.
The Lake Zacapu Garter Snake occurs in Lake Zacapu and the surrounding canals.
The lake is located in the state of Michoacán at 2000 meter above sea level.
The lake borders or is surrounded by the city of Zacapu and it is fed by a large natural spring. The lake is relatively small: 1 kilometer long and 400 meters wide.
The water looks cristal clear and flows gently towards a canal. Via this canal the lake is connected to a complex of canals which provides water for the surrounding agricultural fields.
My breeding group consist of adult boffspring of 2 adult (unrelated) wild caught specimens.
I am breeding this subspecies since 2010.
Literature: Bol, S, 2012. The rediscovery of Thamnophis eques insperatus (the Zacapu Mexican Garter Snake)in Zacapu, Michoácan, Mexico. The garter snake 17 (1): pp-pp. Bol, S. & H. Bruchmann, 2012. Scott’s Mexican Garter Snake (Thamnophis eques scotti; Conant, 2003) in the wild and in captivity. ( Part 1 of 2). The garter snake 17 (3): 15-25. Bol, S. & H. Bruchmann, 2012. Scott’s Mexican Garter Snake (Thamnophis eques scotti; Conant, 2003) in the wild and in captivity. ( Part 2 of 2). The garter snake 17 (24-31): 16-27. Conant, R., 2003. Observations on Garter Snakes of the Thamnophis eques complex in the Lakes of Mexico’s Transvolcanic Belt, with descriptions of New Taxa. American museum novitates 3406: 1-64.