The Boidae family (7 genera, 34 species), are prefrontals medially or nearly touched, infrared sensitive (with labial sensory pits), and neural arches of caudal vertebrae simplified snakes. You can found them in tropical Americas, West Indies, Madagascar, and Southwest Pacific islands. They range 0.6-0.9m to 8-11.5m in body length and the largest living snakes in the world belong to Eunectes. Although regularly observed on the ground, these are in fact, arboreal snakes and prefer to strangle when facing huge prey. They are all viviparous. The epibiotic girdle and hindlimb elements indicate these are primitive snakes that still keep their ancestor’s characteristics in limbs.
We estimated the emergence of Boidae at ~55 Mya using fossil calibrations. Analysis reveal Erycidae and Xenopeltidae are the sister groups of Boidae.