Nicknamed the “ T - Rex of the seas,”Mosasaurswere formidable marine predators of the Cretaceous period . These atrocious , Hydra - similar reptiles could grow to more than17 meters(59 ft ) in length and consequently were n’t afraid to take on a gainsay dinner , likesharks or plesiosaurs .

While we know that these animals were not to be messed with , small was understood about their bringing up biology due to a scarce fossil record of baby or infants . Now , thanks to some new key fossils , Yalescientists have in the end shed some light on how these iconic creature begin their lives . grant to their newPaleontologystudy , these powerful carnivore make birth in the open ocean , rather than travelling to the shores like many other maritime reptiles .

“ Mosasaurs are among the best - studied groups of Mesozoic craniate animals,”explainslead author Daniel Field , “ but evidence regarding how they were born and what babe mosasaur environmental science was like has historically been elusive . ”

For the investigation , scientist canvass the youngest and smallest mosasaur dodo so far find . But these were n’t unexampled specimen ; they had been accumulate more than 100 long time ago and were part of the Yale Peabody Museum ’s assembling . They wield to remain under palaeontologist ’ radars because they were mistakenly key as ancient marine bird , but a reexamination concluded that they were indeed mosasaurs due to a diverseness of unique jaw and tooth features .

Since these highly young specimen were recovered from oceanic deposition , the investigator concluded that neonatal mosasaurs likely lived in the capable ocean and were plausibly also born there .

“ Contrary to classical theories,”saysstudy author Aaron LeBlanc , “ these finding suggest that mosasaurs did not lay egg on beaches and that new-sprung mosasaurs belike did not last in sheltered nearshore nursery . ”

Mosasaurslived during the previous Cretaceous period , some 85 - 65 million years ago , expend their days gobbling down pretty much anything they could get their fierce jaw around . Although these widespread creature were extremely successful killers with few , if any , predators of their own , they became   extinct during theK - thyroxine extinction , or Cretaceous - Tertiary extermination , which saw the loss of around three - quarters of plant and fauna species across the Earth , including the dinosaur .