March 1, 2016
Today let's reflect on the biodiversity of Los Angeles from a deep time perspective. Los Angeles has a unique resource for tracing the legacy of many of the animals that we still see around in this region: the celebrated Tar Pits. Mired in sticky asphalt seeping up to the surface through cracks deep underground, the remains of countless creatures are found at this site in the heart of our city. The gruesome deaths endured by saber-toothed cats, dire wolves, and giant ground sloths as they starved fighting to free themselves from their gooey trap are nearly unimaginable. However, such carnage has left us with the most vivid image of Ice Age L.A., a fossil record that, in addition to various large mammals, includes a myriad of tiny animals. There are also plant remains—branches of all sizes, seeds, and even pollen—which, together with the spectacular record of the animals that once lived in and around what’s today Hancock Park, provide us with unparalleled evidence of the environmental history of Los Angeles over the last 50,000 years.
Thousands of fossils like these have been found at the Tar Pits, in the heart of L.A. For most people the Tar Pits conjure images of extinct mammoths and saber-toothed cats, but the surprising fact is that 90% of the species recorded in the Tar Pits are still alive today. In some ways, the Tar Pits are far more about the present than about the past! For decades, research has focused on a limited number of extinct species that have rightfully captured our imagination. Who wouldn’t daydream of a time when 10-ton mammoths walked the Miracle Mile next to herds of giant camels and huge bison as they were stalked by big cats and the piercing eyes of 10-foot-winged teratorns high in the sky? Just 12,000 years ago, when our ancestors were experimenting with domestication and toying with agriculture, we had a sort of African drama right in our backyard. But as I mentioned above, the Tar Pits have an important role to play in understanding our time and what we will face in the future. The countless fossils of insects and tiny mollusks, small mammals, lizards, fish, and plant remains—collectively known as microfossils—carry critical information about how the environment changes over time around the last glaciation that blanketed much of North America in ice and paved the road for the arrival of humans to this continent and into Southern California. Understanding the ecological transformations of this time is critical for understanding the environmental change we are experiencing today, for such a knowledge places our time into a historical context and give us baselines against which we can compare the present. As such, the Tar Pits are much more than a window into a fascinating past; they stand as an unparalleled resource for framing environmental change in deep time.
One of the many insect microfossils found in the Tar Pits Lately, as I see this tremendous resource waiting to be fully tapped, I have come to think of the Tar Pits as a paleontological metaphor for the Roman god Janus. Citizens of this famed empire used to place sculptures of this two-faced god along the roads, milestones looking both backwards and ahead. Our beloved Tar Pits are in many ways a Janus: one face gazes into a fascinating time, when bygone animals roamed our city, while the other provides an insightful look into today and the future, the road to come.