Early Residents of San Diego

In Mammoths and Mastodons: Titans of the Ice Age, visitors learn about fossil discoveries of these giant creatures all over the world. However, discoveries of fossil proboscideans (elephants, mastodons, gomphotheres, and their common ancestor) have been made at many locations right here in San Diego County! These discoveries have contributed to our understanding of where and when elephants and their kin have lived over time, and how they evolved.


Although today there are only two surviving species of elephants, the Asian elephant (Elephas maximus) and the African elephant (Loxodonta africana), the fossil record reveals that the proboscidean "family tree" was formerly rather bushy, with representatives inhabiting, at one time or another, all continents except Australia and Antarctica. This fossil record begins at least 50 million years ago in Africa and includes periods of speciation, dispersal, and extinction. Proboscideans reached North America from Asia during the middle part of the Miocene Epoch, approximately 15 million years ago.

  • In 1986, remains of a one-million-year-old mammoth, Mammuthus meridionalis, were collected from the Borrego Badlands by professional and avocational paleontologists associated with the Anza-Borrego Desert State Park. These remains include a nearly complete skeleton of an adult individual with tusks measuring almost 10 feet in length. 

  • The fossil beds in the Borrego Badlands have also yielded many remains of a second species of mammoth, Mammuthus columbi . This species occurs at stratigraphic levels that date from about one million to 700,000 years old. Apparently, for a short time, Mammuthus meridionalis and Mammuthus columbi lived together in San Diego County.

  • In the mid-1980s, a retired engineer donated a partial mammoth (Mammuthus sp.) lower jaw with two molars to the Museum. The specimen had been dredged from San Diego Bay in 1965 during construction of a pier at the U.S. Navy’s submarine base. Fossil sea shells adhering to the jaw bone help estimate its age as approximately 100,000 to 200,000 years old.

  • A partial skeleton of the American mastodon, Mammut americanum , was discovered in 1993 during freeway construction improvements to State Route 54 in National City. This specimen includes tusks, molar teeth, vertebrae, and limb bones of an adult individual.

  • Mastodon (Mammut americanum) remains were found in 1994 during construction of the Walmart shopping center along Town Center Drive in Oceanside. These remains include limb bones and vertebrae of an adult individual, as well as skull and limb bones of a newborn calf. 

  • Construction of the Old Grove Marketplace shopping center in 2001 in Oceanside resulted in the discovery of a partial skeleton of an adult Columbian Mammoth (Mammuthus columbi). The recovered fossils include a complete tusk and all four adult molar teeth, as well as portions of skull and lower jaws.

  • In 2002, construction of a housing development in the San Luis Rey River Valley in Oceanside resulted in the discovery by Museum paleontologists of a Mammuthus columbi partial skeleton in ancient oxbow lake deposits dating from approximately 100,000 to 200,000 years ago. Also found in the same sedimentary layer was the partial skeleton of an American mastodon. The skeletons were about 100 feet apart and were arranged as disarticulated bones and teeth scattered along an ancient lakeshore.

  • In 2003, installation of new sewer pipes near the intersection of Ibsen Street and Rosecrans Street near MCRD resulted in the discovery of a single molar tooth of a mammoth (Mammuthus sp.). The tooth was found just above a layer of tropical shell fossils that lived in an ancient precursor of San Diego Bay about 500,000 years ago.

  • Mastodon (Mammut americanum) fossils were unearthed in 2007 near the intersection of College Boulevard and El Camino Real in the northern part of Carlsbad. The remains were discovered in 120,000-year-old river deposits, which also produced fossil bones and teeth of ground sloth, tapir, horse, camel, and deer.