Scientists now believe that gigantic, flipper-bearing mosasaurs – which lived during the Late Cretaceous period – gave birth to their young in the open ocean.
It's understood that the marine lizard populated most waters of the Earth more than 65 million years ago.
They could grow up to 50 feet long and were described by boffins at Yale University and the University of Toronto as "iconic" predators.
A research paper, published in the Palaeontology journal on Friday, claimed to have unearthed new findings about the birthing behaviour of mosasaurs.
Lead author, Daniel Field, said: “Mosasaurs are among the best-studied groups of Mesozoic vertebrate animals, but evidence regarding how they were born and what baby mosasaur ecology was like has historically been elusive.”
The scientists studied specimens that had been collected over 100 years ago.
But, as the abstract to the research explained, "the record of neonatal mosasaur fossils is extremely sparse."
Field and UoT doctoral candidate Aaron LeBlanc argued against the theory that the specimens – which were originally found in deposits in the open ocean – had belonged to ancient marine birds.
"These findings suggest that mosasaurs did not lay eggs on beaches and that newborn mosasaurs likely did not live in sheltered nearshore nurseries,” LeBlanc said. ®