In 1875, professor William Denton identified a tooth from the pits as being from an extinct species we now know as saber-toothed cat. It was not until the early 1900's, when a professor at the university of California, John C. Merriam, who began studying and carrying out research and excavation at the La Brea site on vertebrate and invertebrate paleontology. Upon examination of the fossils within the tar pits, Merriam made key observations which led to further work, and conclusions that La Brea housed fossils of further extent, other than just unlucky cattle, as Denton had found out 25 years earlier.

Merriam carried out the bulk of his research from 1900 to 1919. He and his student Chester Stock described many of the vertebrates from La Brea, including saber-toothed cat (Smilidon californicus), as well as other large cats, wolves, and camels, etc. As his reputation grew with his research and published work, his original researched slowed as he took on more administrative duties as his career advanced. Although he continued to oversee the continuation of what he started with more paleontological research and the continued excavation of La Brea.

Through the work of Merriam, his students, and continued research and excavation of the La Brea tar pits, a premier collection of Pleistocene fossils, has been amassed with more than 500 species found, and in excess of 200 tons of fossil bones recovered from the tar pits.