Eastern Hognose (Heterodon platirhinos)

SPECIES:

Heterodon platirhinos

SYNONYMS:

Heterodon platirhinos LATREILLE, 1801
Coluber heterodon DAUDIN 1803
Originally described by LINNAEUS 1766 as Coluber simus, but this name was later mistakenly associated with the southern hognose snake. The ICZN suspended the law of priority in this case because of the long history of usage (Platt 1985). "platyrhinos" LATREILLE, 1801 was adopted as the next oldest name.

This snake was also identiefied in the early 1900's by Frank Blanchard as Heterodon contortrix
COMMON NAME: Eastern Hognose Snake
COMMON NICKNAMES Puffing adder, spreading adder, false cobra, death adder.

SUBSPECIES:

None

FAMILY:

Serpentes: Colubridae

DISTRIBUTION:

USA (Texas, Oklahoma, Louisiana, Arkansas, Mississippi, Alabama, Georgia, Florida, South Carolina, North Carolina, Tennessee, Kansas, Missouri, Illinois, Indiana, Kentucky, Ohio, West Virginia, Virginia, Pennsylvania, New Jersey, Maryland, Delaware, SE-New York, Connecticut, E-Nebraska, Michigan, Wisconsin, Minnesota, SE-South Dakota), SE-Canada

HABITAT:

The eastern hognose is most common in and along the margins of fallow and cultivated fields, and in or near forests, especially in dry, relatively open areas where sands or porous loams are the principle soils. Easterns are more likely to be found in drier environments and avoid swampy or marshy areas. Inasmuch as toads are the primary food item, eastern hognoses may be most likely to found in areas where toads frequent, especially loose soils where they burrow. While eastern hognoses are considered fossorial, they are usually found abroad during the morning and afternoon hours, foraging for food.

DEFINITION

Largest of the three hognose species, a stout bodied species with males reaching up to 508 mm tail length, and females to 1194 mm. Coloration is highly variable. The dorsum is may be brown, tan, yellowish, grayish, or reddish with brown, black or reddish blotches and tail bands. Some adult easterns may be black or grayish in coloration with little or no patterning. Melanism appears with age, juveniles showing typical patterns until about 300 mm or more in length. There are also reddish, yellowish, and albinistic morphs. Some of the most beautiful morphs are from Richmond, Virginia and Austin, Texas. When present, blotches may number 17 to 28, tail bands 6 to 14, separated by pale interspaces. The venter is usually dark grey or black with white speckling, usually palest on the chin. The tail is lighter than the ventral surface.

The rostral is only moderately upturned and concave dorsally. Supralabials number 8, infralabials between 8-12. There is usually one loreal scale with the oculars arranged in a ring of 8 - 13 scales. The prefrontal scales are fully in contact. The dorsal scales are keeled, in rows of 23 to 25 anteriorly and at midbody and 15 to 20 rows just anterior to the vent. Ventrals number 121 to 146, subcaudals 37 to 60; tail length is 15 to 23% of the total body length. The anal plate (cloacal scute) and subcaudals are divided. Most male easterns have more subcaudals and dark tail bands, longer tails, fewer ventrals, and fewer dark body blotches than females. Some herpetologists believe the wide variation in color and high variability throughout its range is due to the relatively recent development of the Eastern hognose. A successful coloration and pattern has still not yet developed to ensure the survival of the species.

BEHAVIOR

When disturbed, hognoses flatten their head and neck, spreading their vertebrae much like a cobra, owing to their nickname, "puff adder." This act gives the snake an almost impish grin when viewed from head-on. While spreading its "hood," the hognose emits a loud hissing noise like steam escaping from kettle. Occasionally the bluffing snake will repeatedly strike at the would-be attacker but with its mouth closed. If the hissing, hooding and striking fail to dissuade the attacker, the hognose will writhe with its mouth wide open, tongue lolling. Some snakes will eject blood from their lacrymal glands and emit musk from their cloaca. The belief is that a predator will instinctively ignore a dead animal that smells offensive. Of course, if the hognose is righted, it will turn over on its back and again open its mouth.

CHARACTERISTICS

Eastern Hognoses become most active in May when they begin breeding. Females lay between four (4) and sixty (60) eggs in late spring or early summer.

FEEDING BEHAVIOR

Eastern hognosed snakes feed primarily on amphibians with toads and frogs making up the majority of their diet. Due to their slow movement and sluggish behavior, they are most likely ambush predators and opportunitsitc feeders. Throughout their range, Easterns have been observed feeding on great plains, American, southern and spadefoot toads, and various species of cricket, tree, and pond frogs and their tadpoles. Sharp reported observing an Eastern Hognosed snake feeding on a Tiger Salamander (Ambystoma sp).

Since toads and ambystomatids possess toxic secretions in specialized glands on their bodies, species of Heterodon apparently are able to resist the toxic effects. Enlarged adrenal glands in Eastern and Southern hognosed snakes may also nullify the effects of the bufotoxins absorbed during ingestion. In captivity, various species of amphibians as well as redback salamanders, lizards and small mice are taken.

As with other hognosed snakes, platirhinos uses its upturned snout to pursue amphibians as well as burrow into soft soil where it often resides. Although Platt states he has never observed Eastern Hognosed snakes digging up toads in the wild, his finding of large amounts of snad in the digestive tracts of hognosed snakes may relate to ingestion of prey items underground.

COMMENTS

Eastern hognoses are sympatric throughout its range with both the Western hognose and the Southern hognose. There have few if any reports of Eastern hognoses hybridizing with either of the two latter species; of those reports that exist, these are generally under captive conditions.

REFERENCES:

Latreille,P.A. (1801)
XXII Genre. Hétérodon, Heterodon.
In: Sonnini and Latreille, Histoire Naturelle des Reptiles aved figures dessinées d'après nature, Vol. 4: 32-37, Chez Deterville, Paris.

Platt,D.W. (1985)
History and spelling of the name heterodon_platirhinos.
J. Herpetol. 19 (2): 417-418

BIBLIOGRAPHY:

Blanchard, Frank A. 1939. A key to the Snakes of the United States, Canada and Lower California. Ann Arbor, University of Michigan Press.

Conant, Roger, and Joseph T. Collins. 1975 Reptiles and Amphibians of Eastern / Central North America. Houghton, Mifflin

Martoff, Bernard S., et al. Amphibians and Reptiles of the Carolinas and Virginia.1980. UNC Press. Chapel Hill, N.C.

Platt,D.R. (1969)
Natural History of the Hognose Snakes Heterodon platyrhinos and Heterodon nasicus.
University of Kansas, Museum of Natural History, vol 18, No. 4, pp. 253-420.

Note the the moderately upturned snout and clearly defined blotches of this Eastern Hognose from the East Coast of the United States. Photo by Dennis Desmond