Geerat J. Vermeij (born September 28, 1946) is a Dutch-born paleoecologist and evolutionary biologist in the Department of Earth and Planetary Sciences at the University of California, Davis.

[2] He received a MacArthur Fellowship in 1992,[3] and in 2000, was awarded the Daniel Giraud Elliot Medal from the National Academy of Sciences.

Blind from the age of three, he studied Braille at the Prins Alexander Stichting Boarding School in Huis Ter Heide.

His interests in comparing shell traits came his senior year at Princeton University when he took a trip to both Costa Rica and Hawaii.

[1][8] His research argues that an important evolutionary mechanism is the process of escalation, which occurs when species adapt to, or are limited by their competitors, predators, and parasites.