Boas and pythons are less evolved than other snakes as they still retain some lizard-like features, such as a pervic girdle, hind limbs, and a coronoid bone in their lower jaw. These snakes are well known for the way they constrict their prey as a method of killing since they are not poisonous. After suffocating their prey by crushing their ribs they eat the whole.
Pythons are distinguished from boas by having supraorbital bones in their skulls, and laying eggs rather than producing living young. The Green Tree Python and the Emerald Tree Boa are two quite unrelated snakes, as different as any python and boa, but they have evolved to look remarkably similar as they have adapted to their environment.
The Papuan Tree Python (Chondropython viridis) is commonly known as the Green Tree Python, and is found in New Guinea. Its name derives from its green leaf color. The Amazonian Tree Boa (Boa canina) is commonly known as the Emerald Tree Boa, and is found in the tropical areas of South America. Both of these snakes start life as brick red snakes, turn yellow, and then as adulthood approaches become emerald green with cream markings.
With both animals committed to living in the trees they have similar ways of resting in a looped position over branches, and they have larger front teeth than most of the Boidae to allow them to more easily catch prey. A further physical characteristic that they share is a highly developed prehensile tail. You will note this if you ever have the chance to handle green tree pythons.
It is a great example of evolution in action that two species that are not especially closely related have evolved to be so similar as a result of the similarities in the natural environment that they have adapted to. If one were to look for a physical difference it would be that the Green Tree Python grows to around seven feet long, and the Emerald Tree Boa to around six feet.
These snakes will eat birds, lizards and squirrels, and they make use of teeth that are probably the largest in relation to their body of any non-poisonous snake. The way they rest in a coiled position on branches has long made them a favorite of natural history documentaries, although it is rare to see one in captivity. Their arboreal nature makes them somewhat more difficult to care for than other snakes. They do make stunning pets though, and generally do not bite when handled.
