Paleontologists Uncover Three Species of Extinct Walruses in Orange County

Study Gives Insight to Tusk Evolution of the Marine Mammal in new window

Dr. James Parham and Jacob Biewer

November 16, 2020

Cal State Fullerton paleontologists have identified three new walrus species — estimated to be 5 to 10 million years old — discovered in Orange County. One of the new species has “semi-tusks,” or longer teeth. 

The other two new species don’t have tusks, and all three predate the evolution of the long iconic ivory tusks of the modern-day walrus, which lives in the frigid Arctic. Millions of years ago, in the warm Pacific Ocean off the coast of Southern California, walrus species without tusks lived abundantly.

“Orange County is the most important area for fossil walruses in the world,” said geology graduate Jacob Biewer, who conducted the study for his master’s thesis. “This research shows how the walruses evolved with tusks.”

The researchers describe a total of 12 specimens of fossil walruses representing five species from Orange, Los Angeles and Santa Cruz counties. Two of the three new species are represented by specimens of males, females and juveniles.