Snake is a serious threat to humans for the past millions of years so that humans became extremely sensitive to snakes during the long evolution period. The present experiment shows that humans and non-human primates can detect snake pictures more quickly and accurately than those of other animals. Here we performed a flicker paradigm task to compare the accuracy and speed of detection between two types of the target stimuli, which consisted of snake pictures and lizard pictures. We find that the snake target stimuli can be detected more rapidly and accurately than lizard target stimuli. Our study shows that participants were more sensitive to snake pictures during the flicker paradigm task and supports the Snake Detection Theory.