When scientists acquired the first fossilized skull of this species, they soon discovered that the snout had been artificially elongated by fossil dealers to increase its market value. The irritation that this caused is where Irritator got its name.

Thought to hunt on both land and in water, Irritator had narrow jaws much like many modern birds and crocodilians. Research indicates that the lower jaws may have spread out to the sides when opened, like a pelican, to allow Irritator to easily gulp down prey.