Hobbies And Interests
Purpose
The hood serves one clear purpose when it comes to cobras -- intimidation. A cobra will only flare its hood when it feels threatened. The hood sends a signal that the snake feels threatened and is on the verge of striking.
Loose Skin
For people, loose skin might be a negative, but for the cobra, it's a beneficial intimidation technique. The cobra's flap is composed of excess loose skin, just like the skin on its body. However, in order to make the skin stand, it has another component -- ribs. Moveable and retractable ribs are what provide the support when the cobra flairs its hood. Some types of cobras -- such as the Asian Cobra -- have large hoods in proportion to their body, while others -- such as the King Cobra -- have smaller hoods by comparison.
Coloring
The colors of the cobra hood are about the only thing that vary. Most versions come in a combination of colors, from black and white to brown and yellow. The colors tend to flow with the color of the particular species. Many cobras also have specialized designs on the back of the hood, such as the Indian Cobra, which contains eye-like circles on the back of the hood.
Evolution
In regard to evolution, the cobras' expandable hood is beneficial in many circumstances. The key reason behind why it's an intimidation technique is in the ability to make the snake look larger than it is. Colorful designs and patterns -- such as those on the back of some cobra hoods -- often occur in poisonous or venomous species, such as many poisonous frog species from the Amazon region, or the Coral Snake with its red, yellow and black coloration patterns.