From the robust boa constrictor to the venomous rattlesnake, all of the more than 3,400 snake species that slither today may have descended from the same prehistoric forest prowler, whose sinuous body had two small hind legs with toes and ankles, researchers reported on Tuesday.

After analyzing data gathered through fossils, genetic sequencing and anatomical comparisons of 73 snake and lizard species, a team of paleontologists from Yale University has constructed what it calls the most comprehensive snake “family tree” to date. The findings provide an answer to longstanding questions about when, where and how modern snakes originated.

“Having that tree as a backbone let us draw a ton of conclusions for what the ancestral snake would have been like,” said Daniel J. Field, a doctoral candidate in evolutionary biology and an author of the study. The team concluded that the most recent common ancestor of all living snakes was nocturnal, thrived 128.5 million years ago in the Southern Hemisphere and devoured relatively large prey whole using its sharp, hooked teeth as a hunting tool.

To reach this conclusion, the team’s first step was to reconstruct the snake’s family tree from tips to its trunk. To better understand when certain characteristics — like the ability to constrict prey or hunt at night — first appeared, the researchers used the genetic and morphological data they collected to piece together how different groups of living snakes are related to one another.