Yellowbelly Racer (Coluber constrictor flaviventris)

Note: With many thanks to Gerry Salmon for confirming our ID.

9 May 2016
Greenbelt Corridor Ray Roberts/Lewisville Lake FM 428 Access Area, Aubrey Branch
Denton County, Texas

We may or may not be correct with the ID. Your assistance in making the correct ID is greatly appreciated. This was a large snake and one could tell right away that it was non-venomous. It was in the range of 4-5 feet in length with the latter part of its body hidden in the tall grass. It was observed for only a minute or two sunning atop the matted green prairie grasses but once we attempted to move to try and get a better angle on our camera, it slithered off effortlessly and away from us. The only thing at our end to see and hear was its fast-disappearing body and the smooth rustling sound it made. We'd never before observed this snake in the field. If it is what online is called the Eastern Yellow-bellied Racer and on iNat is called the Yellowbelly Racer, then it is a snake that is found across much of the United States and the species proper, Coluber constrictor, occurs coast to coast (see sources below). This particular subspecies is found across most of Texas (see the range map by county presented at the Southwestern Center for Herpetological Research). Texas is home to six of the 11 known subspecies of Racer snakes including the subspecies presented in our observation, flaviventris. The Mexican Racer (subspecies Coluber constrictor oaxaca) extends into the northeast region of Tamaulipas that shares the international border with Texas. Chihuahua and Coahuila which also share the border with the United States are home to the Eastern Racer (ssp. flaviventris) in areas that are close to the Río Bravo/Río Grande (see range map provided by California Herps). One of the sources consulted indicated that this snake is a "nervous" snake and therefore does not do well in captivity and for the same reason is prone to bite when handled. Yellowbelly Racer is an authentic resident of North America and the Western Hemisphere. The Greenbelt Corridor is administered by the Texas Parks and Wildlife Department.

Sources:

"Eastern Yellow-bellied Racer," Southwestern Center for Herpetological Research, photographs, Texas range map by county, accessed 5.10.16, http://southwesternherp.com/snakes/flaviventris.html

"Eastern Yellow-Bellied Racer (Adult)," Texas Snakes & More, photograph, short description, accessed 5.10.16, http://www.texassnakes.net/Racer.htm

"Eastern Yellow-Bellied Racer - Coluber constrictor flaviventris," Missouri Department of Conservation, photographs, description, accessed 5.10.16, http://nature.mdc.mo.gov/discover-nature/field-guide/eastern-yellow-bellied-racer

"North American Racer - Coluber constrictor," Montana State Government, photographs, range maps, see especially the NatureServe range map for this snake in the Western Hemisphere, description, accessed 5.10.16, http://fieldguide.mt.gov/speciesDetail.aspx?elcode=ARADB07010

"Racer (Coluber constrictor)," South Dakota Game, Fish, and Parks, photographs, description, accessed 5.9.16, https://gfp.sd.gov/wildlife/critters/amphibians-reptiles/snakes/racer-snake.aspx

"Western Yellow-bellied Racer - Coluber constrictor mormon," California Herps, range maps, photographs, description, accessed 5.10.16, http://www.californiaherps.com/snakes/pages/c.c.mormon.html