A West Texas researcher recently came across a dead rattlesnake and was shocked to find that the snake appears to have died of its own bite. He posted the photo below to the Rolling Plains Quail Research Ranch Facebook account.
His post described the find as follows:
While I was tracking a covey of bobwhites the other day I stumbled across this 4ft long, dead western diamondback. After a closer examination, it appeared that the snake may have died from self envenomation. One of its fangs was still punctured into its own back when I found it and the body was still fresh. Most venomous snakes are believed to have some immunity to their own venom, but there are a few cases of fatal self envenomation.
This is apparently pretty rare, but his post goes on to say that in case where a snake is killed by its own venom, other factors like stress or disease are usually involved. A similar incident was captured in the 2018 YouTube video below. The snake actually bites itself on camera and dies immediately.