Mosasaurus

No, Mosasaurus was not a dinosaur. It was a giant marine reptile and a close relative of modern lizards and snakes.12

The largest species, Mosasaurus hoffmanni, may have reached 17 to 18 metres (56 to 59 ft), though many scientists think 11 to 12 metres (36 to 39 ft) is more likely. Other species were about 8 to 10 metres (26 to 33 ft) long.12

Mosasaurus was a carnivore that ate fish, sharks, squid, birds, sea turtles, and even other mosasaurs. It could swallow very large prey thanks to a special hinge in its jaw.132

Mosasaurus lived during the Late Cretaceous Period, from about 82 to 66 million years ago, when it went extinct along with the dinosaurs.2

Probably up to about 26 km/h (16 mph) in a short burst, about as fast as a grown-up riding a bike. This is an estimate. Mosasaurus swam by swishing its tail, but it probably could not swim very fast for long.34

Adult Mosasaurus had no natural predators, but young ones were hunted by sharks and giant fish. Mosasaurs also fought and sometimes ate each other.32

Mosasaurus fossils have been found in North and South America, Europe, Africa, Western Asia, and Antarctica, showing it lived in oceans all over the world.2

Yes, Mosasaurus was longer than T. rex. The largest Mosasaurus species could reach 17 to 18 metres (56 to 59 ft) long, while T. rex was about 12 metres (40 ft) long.12

No, Mosasaurus gave birth to live young in the open ocean. Scientists found a fossil of a pregnant mosasaur with five babies inside.13

Mosasaurus went extinct about 66 million years ago, at the same time as the dinosaurs, likely because of the asteroid impact that caused a mass extinction.2