Tim Friede, a self-taught snake expert from California, injected himself with snake venom more than 650 times over the course of nearly two decades. Now, experts hope his experiments and blood can help scientists develop a new antivenom.

Californian autodidact herpetologist Tim Friede has spent the last two decades deliberately injecting himself with hundreds of snake venom shots, all in an attempt to make him immune to fatal

The man was found to have undertaken "escalating doses" from 16 snake species so lethal they "would normally a kill a horse."