Bullsnake

Lewis and Clark killed and described a bullsnake on August 5, 1804, on the bank of the Missouri River in present-day Harrison County, Iowa. Lewis noted it had no poison teeth and described its characteristic bellowing sound, explaining that it was “called the cow or bull snake from a bellowing nois which it is said sometimes to make resembling that anamal.” This large, nonvenomous constrictor was well known to frontier settlers but poorly documented scientifically.

Journal Excerpt

Lewis, August 5, 1804: "Killed a serpent on the bank of the river adjoining a large prarie… it had no poison teeth and therefore think him perfectly inocent; it is called the cow or bull snake from a bellowing nois which it is said sometimes to make resembling that anamal, tho' as to this fact I am unable to attest it never having heard them make that or any other nois myself."