On both trips to South Africa we only saw one snake but both times it was a Puff Adder. These snakes are responsible for more human bites than all other African snakes combined. As you can see they are a fat, sluggish snake.
Wise advise from FACTzoo.com : Dealing with snakes Humans kill many more snakes than snakes kill humans. Leave the snake alone and it will leave you alone. Most bites occur when people attempt to kill snakes. You are statistically more likely to be struck by lightning or kicked to death by a donkey than to die of a snakebite. More people die of human bites in South Africa than of snake bites. (Shown here: injury due to venom from a Puff Adder.)