North American Hognose Snake (Heterodon spp.)
Published: February 13, 2018 Last Updated: September 30, 2020
North American hognose snakes are a non-medically significant venomous genus of fossorial colubrid snakes native to southern Canada, northern Mexico, and most of the United States. There are actually 3 recognized genera of “hognose” snakes:
- Heterodon (North America)
- Lystrophis (South America)
- Leioheterodon (Madagascar)
Although unrelated, these snakes look like they could be cousins. That is due to a phenomenon called convergent evolution — when unrelated species evolve similar traits as a result of adapting to similar habitats/ecological niches.
This hognose snake care guide discusses the three species of Heterodon, North American hognose snakes:
- Eastern hognose (Heterodon platirhinos)
- Western hognose (Heterodon nasicus)
- Southern hognose (Heterodon simus)
North American hognose snakes have a variety of common names (though misleading): “puff adders” (not to be confused with African vipers), “spreadheads,” “hissing adders,” “sand adders,” “spreading vipers,” “blowing vipers,” and “blow snakes.” Fearsome titles for such adorable little snakes!
Many of these common names reference the hognose’s extensive repertoire of defensive behaviors. If they feel threatened by a potential predator (including humans), they may expand the ribs along the front of their body, cobra-like, to make themselves appear bigger. This display is often accompanied by loud hissing. But hognoses are most famous for their dramatic act of playing dead:
Hognose snakes are characterized by short faces with upturned, pig-like snouts used for digging in sandy soil and unearthing buried toads. They have keeled, matte scales along the length of their body, although coloring and pattern vary based on species. They also have round pupils, indicating that they are active during the day (diurnal), although they are most active during the morning and late afternoon hours.
Depending on the gender and species, hognoses can be anywhere between 14”-46” (36-117cm) long, with females tending to be much larger than the males. Hognose snakes live between 10-15 years in captivity, although there is at least one known case of an 18-year-old hognose.
Like other snakes, hognoses are carnivores, which means that more than 90% of their diet comes from eating animals. Although they are considered toad specialists (especially H. platirhinos and H. simus), they actually eat a variety of amphibians as well as reptiles and occasionally small mammals. Hognoses are not constrictors, instead relying on their venom to make their prey manageable.
Hognoses are technically considered “rear-fanged venomous” because instead of fangs at the front of their jaws like most snakes, the fangs are placed at the back of the upper jaw. Venom delivery is via grooved (not hollow) fangs connected to Duvernoy’s glands, which means that chewing is required for full envenomation of prey. Venom is not present in hognose saliva. Fortunately, hognose venom is specialized for amphibians, making it relatively harmless to humans and does not require medical attention. More information on hognose venom and its effects in Hognose Handling Tips.
According to the IUCN Red List of Threatened Species, H. platirhinos and H. nasicus are categorized as species of Least Concern, but H. simus is labeled as Vulnerable. Often North American hognoses are mistaken for copperheads or rattlesnakes and killed by humans.
- Contrary to popular belief, hognose snakes’ rear fangs are not used to puncture inflated toads for easier swallowing. This is contradicted by venomologist Dr. Bryan Fry, who asserts that the fangs are only used for venom delivery.
- Hognose snakes are immune to toad toxin. They possess enlarged adrenal glands that produce extra adrenalin to counteract the effects of the digitaloid toxin produced by toads. Normally this toxin slows a predator’s heart until it eventually stops, but hognoses are unaffected. (“Adrenal Enlargement and Its Significance in the Hognose Snakes (Heterodon)” by Hobart M. Smith and Fred N. White)
- Hognose snakes are illegal to keep in some parts of the US. Consult your state and local laws for potential bans.
Hognose Snake Care Guide — Table of Contents
- Shopping List: Everything You Need for a Pet Hognose Snake
- Species of the Heterodon Genus
- Terrarium Size Guidelines
- Temperature & Humidity Requirements
- Substrate Options for Hognose Snakes
- Environmental Enrichment: Decorating the Terrarium
- Feeding Your Hognose Snake
- Handling Tips & Body Language Info
- Common Diseases & Hognose Health Questions
- Additional Resources
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