In 1914, Cartier first commissioned Georges Barbier of Gazette du bon ton fame to illustrate an invitation card showing a woman with a panther.* His watchmaker and principal designer, Charles Jacqueau, then produced a timepiece in 1915 of an abstract panther design, using onyx and diamonds to depict the cat's coat - the first use of the panther motif in Cartier jewelry.
The panther, now so synonymous with Cartier, was a prominent icon of the Art Deco period. According to an article in ProfessionalJeweler.com magazine, unlike the "leisurely Edwardian era" the big cat "symbolized the human nature as untamed and unpredictable, covered by a thin veneer of civilized culture." The Jazz Age era of flappers, Prohibition, gangsters, and fast livin' was well served by an image of a sleekly beautiful, but incredibly dangerous animal.
* For more on this, check out Made by Cartier: 150 Years of Tradition & Innovation by Franco Cologni and Ettore Mocchetti.