The cobra's hood, very cool. But how does it work? A study in the Journal of Experimental Biology takes a look at just that.
Cobras belong to the Elapidae family of snakes. This is a family of venomous snakes which are found in tropical and subtropical regions around the world. Skeletally, the bones in the hood of the cobra evolved from ribs and the associated muscles evolved along with them. Scientists have taken a look at the cobra's defensive display, the "hood flare," and measured the electrical activity coming from the snakes' hood muscles to tease out which muscles are involved in the movement. This experiment found 8 muscles involved in the hood flare. Interestingly, these muscles are also present in non-hooding snakes. The muscles and the nervous system's control over them have evolved to spread the snake's hood. While this research was mostly identifying the muscles themselves, further research will delve into the evolution of these muscles in various snake species.
Here's the story: http://news.bbc.co.uk/2/hi/science/nature/8625553.stm