So, what are the largest predators that have ever lived in North America.

As for furry animals, North America's largest predatory mammal was probably the massive short-faced bear (Arctodus simus), said Ross MacPhee, senior curator of mammals at the American Museum of Natural History in New York City.

It can be difficult for scientists to gauge the exact body weight of an extinct species, because they have to extrapolate those numbers using existing species as benchmarks, MacPhee told Live Science in an email.

Modern polar bears (Ursus maritimus) aren't too far off — the largest males stand around 5 feet (1.5 m) at the shoulder and weigh around 1,300 pounds (600 kg), according to Polar Bears International. .

The largest predatory North American dinosaur is also the continent's most famous: the king, Tyrannosaurus rex. .

During the late Cretaceous period, about 100 million to 66 million years ago, North America was a land of monsters.

"Carnivorous dinosaurs had incredible variety in North America across the Mesozoic [252 million to 66 million years ago]," Andrew Farke, director of the Raymond M.

Alf Museum of Paleontology in Claremont, California, told Live Science in an emailT

rex's length but was lighter, weighing 6.8 tons (6.1 metric tons), compared with T.

rex's 7.8 tons (7.1 metric tons), according to the American Museum of Natural History.

rex used all that bulk to its advantage: With its powerful jaw muscles, it could deliver up to 6 tons (5.4 metric tons) of pressure per bite — enough to tear through steel as if it were a piece of paper, according to a 2019 study in the journal The Anatomical Record.

The only dinosaurs alive today are birds, making the largest living dinosaur in North America the California condor (Gymnogyps californianus).

In the late Triassic period, roughly 237 million years ago, an ichthyosaur known as Shonisaurus sikanniensis began swimming in the waters of what is now British Columbia, Canada.

sikanniensis is regarded as the largest known marine reptile of all time," Kenshu Shimada, a professor of paleobiology at DePaul University in Chicago, told Live Science?