These snakes are usually referred to by local herpers as "subocs".
This snake was formerly classified as Elaphe. It is unusual in that it possesses 40 pairs of chromosomes rather than the normal 36-38 pairs.
It is an excellent climber. I have watched a large suboc climbing down a sheer vertical rock surface which offerred no apparent grip. They are generally a docile snake, although I have found a few which have hissed or bitten. When spotted, they rarely try to escape. I have found specimens on the road which have lain immobile while I have photographed them; they did not become active until touched.
I have found that the larger specimens (over four feet) frequently are difficult to get feeding on laboratory animals. They usually feed well on kangaroo rats and other wild rodents. The smaller specimens (under three feet) usually feed well in captivity.
They tend to breed later in the year than most of the colubrids in the area, usually in June and July. The normal hatchings for wild caught specimens are in early to mid October.I found one gravid female whose eggs did not hatch until November 24, after eleven weeks of incubation at ambient room temperature. The normal hatch time for my suboc eggs has been 73-78 days. When kept together, the neonates have been aggressive. When separated, they have calmed down.
I have long felt , since many suboc eggs are laid late in the year, that they winter in the egg and hatch in the spring. This is based on the number of neonate subocs which I have found in April and May which are still hatchling size and still bear the umbilical scar.
The juveniles (and adults) will eat amazingly large prey. I have seen juvenile subocs which have barely been able to move - they just pivoted on the lump made by the meal. I once found a 38" suboc about 16 feet up a sheer rock cut, lying on a narrow crevice. It had just eaten a ground squirrel. I have no idea how it was able to climb to its location.
This suboc was photographed at night on a rock cut north of Loma Alta, northeastern Val Verde County. It is about 4.5 feet long.
This was my first suboc, a juvenile collected on Hwy. 54 north of Van Horn, Culberson County, in 1972.