|Adult southern hog-nosed snake|
|Red phase southern hog-nosed snake|
The dorsal color pattern consists of a light brown, yellowish, grayish, or reddish ground color, overlaid with a distinct row of dark blotches that alternate with smaller blotches on the flanks. The belly is distinctly darker in color than the underside of the tail in juveniles. As the snake ages, the underside usually becomes a pale white. 
This species is oviparous. Sexually mature adults mate from April through August. The thin-shelled, leathery, whitish eggs are laid in clutches of 6-14. After 55-60 days the eggs hatch. Each hatchling is 15-18 cm (6-7 inches) in total length.
This species is classified as Vulnerable (VU) on the IUCN Red List of Threatened Species with the following criteria: C1+2a(i) (v3.1, 2001). A species is listed as such when the best available evidence indicates that the population size is estimated to number fewer than 10,000 mature individuals, a decline of at least 10% is estimated to continue within 10 years or three generations, whichever is longer, (up to a maximum of 100 years in the future), and a continuing decline has been observed, projected, or inferred, in numbers of mature individuals and no subpopulation is estimated to contain more than 1,000 mature individuals. It is therefore considered to be facing a high risk of extinction in the wild. The population trend is down. Year assessed: 2007. The Alabama Department of Conservation and Natural Resources has listed the species as possibly extirpated within the state.
- Stejneger, L.H., and T. Barbour. 1917. A Check List of North American Amphibians and Reptiles. Harvard University Press. Cambridge, Massachusetts. 125 pp. (Heterodon simus, p. 77.)
- "Heterodon simus". Integrated Taxonomic Information System. Retrieved 14 September 2007.
- Behler, J.L., and F.W. King. 1979. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf. New York. 743 pp. LCCCN 79-2217. ISBN 0-394-50824-6.
- Wright, A.H., and A.A. Wright. 1957. Handbook of Snakes of the United States and Canada. Comstock. Ithaca and London. 1,105 pp. (in 2 volumes) (Heterodon simus, pp. 312-314, Figure 96. + Map 28. on p. 298.)
- "Heterodon simus at Florida Museum of Natural History". Retrieved 16 May 2013.
- Heterodon simus at the IUCN Red List. Accessed 14 September 2007.
- 2001 Categories & Criteria (version 3.1) at the IUCN Red List. Accessed 14 September 2007.
- "Snakes in Alabama". Outdoor Alabama. Alabama Department of Conservation and Natural Resources. Retrieved June 6, 2012.
- Conant, R. 1975. A Field Guide to Reptiles and Amphibians of Eastern and Central North America, Second Edition. Houghton Mifflin. Boston. xviii + 429 pp. ISBN 0-395-19979-4 (hardcover), ISBN 0-395-19977-8 (paperback). (Heterodon simus, p. 170 + Plate 25 + Map 132.)
- Conant, R., and William Bridges. 1939. What Snake Is That? A Field Guide to the Snakes of the United States East of the Rocky Mountains. (With 108 drawings by Edmond Malnate.) D. Appleton-Century. New York and London. Frontispiece map + viii + 163 pp. + Plates A-C, 1-32. (Heterodon simus, p. 41 + Plate 5, Figure 13.)
- Linnaeus, C. 1766. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, diferentiis, synonymis, locis. Tomus I. Editio Duodecima, Reformata. L. Salvius. Stockholm. 532 pp. (Coluber simus, p. 375.)
- Schmidt, K.P., and D. Dwight Davis. 1941. Field Book of Snakes of the United States and Canada. G.P. Putnam's Sons. New York. 365 pp. (Heterodon simus, pp. 116-118, Figures 25-26.)