Western Hognose Snake

Heterodon nasicus

The habitats of the Western Hognose Snakes are found in shortgrass prairies, dry rocky lands, and coastal islands (Weinstein and Keyler et al. 2008).
Primary Literature Article: Size and Demographic Structure of an Isolated Population of Western Hognose Snakes, Heterodon nasicus, in Northern Illinois. (Kolbe et al. 1999)

• Kingdom: Animalia (Weinstein and Keyler et al. 2008)

• Phylum: Chordata

• Subphylum: Vertebrata

• Class: Reptilia

• Order: Squamata

• Suborder: Serpentes

• Family: Colubridae

• Genus: Heterodon

• Species: Heterodon nasicus

The snakes produce sexually by laying eggs (Kerns, M. 2003).
Their mating season is from June to August and they hibernate from September to March (Kerns, M. 2003).
They move to warmer or cooler areas to maintain a certain body temperature (Kerns, M. 2003).
Hognose snakes are small to medium in size. (Weinstein and Keyler et al. 2008)
The snake's most distinct characteristic is their upturned nose, which is used for digging (Kerns, M. 2003).
Their geographic range includes southern Canada to northern Mexico and from Colorado to Illinois (Weinstein and Keyler et al. 2008).
Prey include mammals, amphibians, reptiles, and eggs. Toads are the main prey for the snakes. (Kerns, M. 2003).

This experiment was done to estimate the population size and assess the demographic structure of the western hognose snake population in northwestern Illinois. The Western Hognose Snake was a threatened species in the state of Illinois, so any information on the species in the state that could be found was valuable (Kolbe et al. 1999).
The study site was a sand prairie on the eastern bank of the Mississippi river in Illinois. The snakes were captured by hand, weighed, and then their snout vent lengths were measured and all the data was recored (Kolbe et al. 1999).
73 snakes were captured
34 females
25 males
14 unsexed (juvenile)

The female population showed significantly longer snout-vent lengths than the male and unsexed populations (Kolbe et al. 1999).
The unsexed population showed mostly longer snout- vent lengths than the male population (Kolbe et al. 1999).
36 snakes in the 150-300 mm size classes, which were mostly unsexed (juvenile) (Kolbe et al. 1999).
19 snakes in the 400-500 mm size classes, which were mostly adult females (Kolbe et al. 1999).
Other factors observed:
- Eating habits- consumption of turtle eggs at the study site (Kolbe et al. 1999).
- Human threats to the population- cabins, roads, a boat ramp, and a newly constructed bike path (Kolbe et al. 1999).

Kolbe, Jason J. 1999. “Size and Demographic Structure of an Isolated Population of Western Hognose Snakes, Heterodon nasicus, in Northern Illinois.” Chicago Herp. 34(6): 149-152
Weinstein, Scott A. and Keyler, Daniel E. 2009. “Local Envenoming by the Western hognose snake (Heterodon nasicus): A case report and review of medically significant Heterodon bites.” Toxicon. 54(3): 354-360
Kerns, M. 2003. “Heterodon nasicus” (On-line), Animal Diversity Web. Accessed January 23, 2023 at https://animaldiversity.org/site/accounts/information/Heterodon_nasicus.html

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