George Cuvier

Cuvier analyzed fossils of large mammals such as mammoths and the giant ground sloth Megatherium, demonstrating in a landmark 1796 paper that they belonged to species no longer living. By comparing fossil elephant remains to living Indian and African elephants, he showed that entire species had permanently died out, directly challenging the prevailing belief that no animal could go extinct.

Cuvier proposed that Earth's history was punctuated by sudden, catastrophic events that destroyed whole groups of organisms, after which new species appeared. This placed him in direct opposition to Jean-Baptiste Lamarck, who argued for gradual species transformation.

Working from fossil bones sent from South America, Cuvier applied comparative anatomy to reconstruct Megatherium in 1796, identifying it as a giant extinct ground sloth rather than an elephant or hippopotamus as others had guessed. This reconstruction demonstrated that extinct animals could be scientifically identified and classified from their remains alone.

Cuvier spent his career at the Muséum national d'Histoire naturelle in Paris, where he held the chair of comparative anatomy. He also served in senior government positions under Napoleon and later the restored Bourbon monarchy, making him one of the most politically powerful scientists in early nineteenth-century France.