All snakes are not poisonous. Some snake kill their prey by wrapping themselves tightly around it. These snake are called constrictors. Boas and python belong to this family. while some constrictors are just a few inch long, others, like the boas constrictor, can measure over 18 feet. One of the largest snake in the world, the Anaconda of South Africa, is a boa constrictor. These snake have very thick, muscular bodies.
Python and boas cannot see very well. Instead, they use their tongue to sense the scent of their surroundings. They dart their forked tongue in and out to detect food. They also have heat sensors near their nostrils to locate warm-blooded animals. Boas and python also have heat pit located on their heads. These temperature-sensing organs are so sensitive that the snakes can effectively sense even a slight change of 0.002 Degre celsius. This helps them to navigate and find their prey in the dark.
Source: https://www.youtube.com/watch?v=jqmLfSU-G5s
