8. Boomslang

About 24 hours after being bitten on the thumb by a juvenile boomslang (also called a South African green tree snake), herpetologist Karl Patterson Schmidt died from internal bleeding from his eyes, lungs, kidneys, heart and brain, researchers reported in 2017 in the journal Biochimica et Biophysica Acta. The snake had been sent to Schmidt at The Field Museum in Chicago for identification. Like others in the field at the time (1890), Schmidt believed that rear-fanged snakes like the boomslang (Dispholidus typus) couldn't produce a venom dose big enough to be fatal to humans. They were wrong.