BE ADVISED: On Saturday 9/20, the Los Angeles Memorial Coliseum will host the USC vs. Michigan State football game. Kickoff is at 8 pm. This event will impact traffic, parking, and wayfinding in the area due to street closures. Please consider riding the Metro E (Expo) Line and exiting at USC/Expo station.

Mind-Blown Science: Dr. Luis Chiappe and NHM's Extraordinary Plesiosaur

Dr. Luis Chiappe, Director of our Dinosaur Institute, explains why this giant marine reptile blows his mind.

pregnant plesiosaur in dinosaur hall

Plesiosaurs were a diverse family of giant marine reptiles (not dinosaurs) that lived during the Mesozoic Era. They typically had broad bodies, short tails, and large flippers. They were among the top predators in the Western Interior Seaway, the large inland sea that existed during the Cretaceous period stretching from the Gulf of Mexico to the Arctic Ocean. 

This extraordinary mounted Plesiosaur skeleton in the Dinosaur Hall shows us a rare surprise. A closer look shows a baby’s skeleton inside her, showing scientists that Plesiosaurs had live births during the age of dinosaurs.