North American Hognose Snakes are not endangered...they might be considered "threatened in some areas".but definitely not in danger of extinction.
A specific species would be helpful (scientific name). Some might consider the Madagascar Hognose to be endangered but c'mon, honestly, any species that is confined to an island is going to enjoy relatively few population numbers even under the best of ecological circumstances.
Answers: Like some other snakes, Hognose snakes are endangered because inhabitants are taking over their habitat and killing off the population. Some people are not cognizant and kill snakes like the hognose because they are afraid and do not know how to respect their living. Because of this the numbers are decreasing and we need to minister to people understand that snakes are not evil and do not pose a threat to the human society and will not kill of or species. Snakes are more afraid of us later we are of them. They do not hunt you down like some people propose and they wont attack you unless you somehow make them consistency aggressive.