Storeria occipitomaculata, commonly known as the redbelly snake or the red-bellied snake, is a species of harmless snake in the subfamily Natricinae of the family Colubridae. The species is native to North America (Canada and the United States).
Description Storeria occipitomaculata is a small woodland species that usually measures 4–10 in (10–25 cm) in total length (including tail). Its dorsal color ranges from orange to gray, black, or brown. It can be distinguished from other species by its bright red or orange underbelly. Many individuals have a light brown ring behind the head.
Habitat Storeria occipitomaculata prefers warmer habitats, and in the more northern limits of its range will inhabit abandoned ant mounds. These mounds absorb solar radiation and are insulated which allows for a longer active season. This species, with large eyes and a kinetic skull, is not able to burrow on its own effectively, and abandoned ant mounds allow it access to a warm retreat. Individuals of this species can be found under logs and leafy debris due to its secretive nature.
Reproduction Storeria occipitomaculata bears live young by ovoviviparity. Studies of the redbelly snake have determined that it reproduces annually, and females have been found to be gravid during spring and early summer. While body size varies throughout the redbelly snake's geographic range, the average litter size tends to remain the same with an average of 7–9 young per litter. The redbelly snake begins mating at around two years of age and must be a minimum of in order to reach sexual maturity.
Diet The red-bellied snake, like other members of its genus, preys primarily on slugs. Its teeth are slender and distally curved to better catch slimy prey.
Behavior Storeria occipitomaculata exhibits a distinctive behavior of lip-curling.Do Amaral, José Pedro Sousa (1999). "Lip-curling in redbelly snakes (Storeria occipitomaculata): Functional morphology and ecological significance". Journal of Zoology 248 (3): 289–293. The purposes of this behavior are still being studied, but are hypothesized to aid in prey capture and handling, and in predator deterrence. The redbelly snake has also exhibited death-feigning behavior to possible predators, in which it laterally compresses parts of its body to mimic the appearance of injuries. It can also mock the posture of venomous snakes by flattening its body, raising its head, and flexing its neck.
Etymology The specific name, occipitomaculata, is derived from the Latin words occiput which means "the back part of the head" and maculata meaning "spotted". The generic name, Storeria, of the monophyletic cladePyron RA, Hsieh FW, Lemmon AR, Lemmon EM, Hendry CR (2016). "Integrating phylogenomic and morphological data to assess candidate species-delimitation models in brown and red-bellied snakes (Storeria)". Zoological Journal of the Linnean Society 177 (4): 937–949. doi:10.1111/zoj.12392 honors zoologist David Humphreys Storer. xiii + 296 pp.
Subspecies Three subspecies, including the nominotypical subspecies, are recognized as being valid: Florida redbelly snake – Storeria occipitomaculata obscura Trapido, 1944 Northern redbelly snake – Storeria occipitomaculata occipitomaculata (Storer, 1839) Black Hills redbelly snake – Storeria occipitomaculata pahasapae H.M. Smith, 1963
Nota bene: A trinomial authority in parentheses indicates that the subspecies was originally described in a genus other than Storeria.
References
Further reading 743 pp. (Storeria occipitomaculata, pp. 655–656 + Plates 501, 505–506). xiii + 448 pp. + Plates I–XXVIII. (Ischnognathus occipitomaculatus, pp. 287–288). xiv + 494 pp., 47 color plates, 207 figures. (Storeria occipitomaculata, pp. 424-426, Figure 194 + Plate 42). 365 pp., 34 plates, 103 figures. (Storeria occipitomaculata, pp. 229-230, Figure 74). (Storeria occipitomaculata, pp. 160–161). Storer, D.H. (1839). Reports on the Fishes, Reptiles and Birds of Massachusetts. Boston: Commissioners on the Zoological and Botanical Survey of the State. (Dutton and Wentworth, State Printers). xii + 426 pp. ("C[oluber]. occipito-maculatus", new species, p. 230). 1,105 pp. (in two volumes). (Storeria occipitomaculata, pp. 714–721, Figures 210–211, Map 54).
External links Redbelly Snake, Reptiles and Amphibians of Iowa Red-bellied Snake, Illinois Natural History Survey