fossiling.com

Tar, Baby

Rancho La Brea


The first time I visited Los Angeles my host Howard reveled in the opportunity to play tour guide. Would I like to see the Hollywood Walk of Fame, Venice Beach, The Getty, he offered? No, I said, none of those. I knew where I wanted to go. I wanted to see the Tar Pits. To his credit he hardly missed a beat, then optioned, “Or, we could do the Tar Pits.”

The La Brea Tar Pits loomed large in my childhood. We had a book that dramatically depicted a snarling saber tooth menacing a mammoth woefully mired in asphalt. Rancho La Brea is one of the most famous and productive fossil sites in the world. The pits have disgorged millions of Ice Age remains over the last century. They’re also unique in being situated smack dab in the middle of the second largest city in the U.S. Where museums in New York and Chicago import their fossils from the hinterlands, in the City of Angels they dig them up along the Miracle Mile.

Hancock Park occupies 23 acres of neatly trimmed lawn hemmed by the office towers of Wilshire Boulevard and the LA County Museum of Art. The first thing you notice is the entire neighborhood smells like freshly surfaced road, not too odd in an urban setting. But meander off the footpaths and you risk soiling your shoes in sticky tar seeps lurking in the grass. The black stuff just oozes up out of the ground wherever it wants.


    Mammoths in peril, the Page Museum beyond, Hancock Park, LA.


At the heart of the park sprawls what at first glance looks like a placid pond -- until great bubbles of methane belch up, roiling the veneer of surface water to reveal the ebony depths below. At one end of the Lake Pit a family of mammoths, one plunked struggling in the tar, gathers by the shore. Other life sized statues of Pleistocene giants dot the park: ground sloths, bear, mastodon. Pedestals topped by paleolithic lions and Saber Toothed Cats flank the entrance of the Page Museum, a corporate-modern building half buried under a grassy slope.

The first display you meet inside the museum is a holographic Saber Toothed Cat that cycles in seconds from skeleton to fully furred feline. If one learns anything at the Page it is not to call the California state fossil a “tiger”. With its nine inch canines this prehistoric progenitor makes the average Bengal or Siberian look downright cuddly.

Buried bunker-like as it is, the museum has a central atrium in place of windows. A parade of impressive skeletons circles this verdant core. A hulking Harlan’s Ground Sloth greets visitors exiting the orientation theater. A slightly humbler Shasta sloth lumbers nearby. These are accompanied by an Ancestral Bison, a mastodon and calf,  a giant camel, and a towering Columbian Mammoth with tusks as long as its entire body. There’s an example of a prehistoric horse that went extinct, leaving the Americas equine bereft until conquistadors repatriated their descendants millennia later. The long legged, short faced bear beside it would beggar a grizzly,  while the saber toothed cat is the size of an African Lion and the American Lion is even bigger than that.


    The State Fossil, Smilodon Californicus; mastodon & calf Mammut americanum.


The bones are stained a range of shades from caramel to black. Otherwise their preservation is astonishing, and most are the real fossils, not casts (the rare Shasta specimen is an exception). The same can’t be said of the mammoth and mastodon tusks, they’re made of fiberglass. Apparently the tar preserves bone down to the finest details, but corrodes ivory.

A long wall case displays a smattering of the 600 species pulled from the pits. These include coyotes, badgers, skunks, gophers, mice, weasels, rabbits, antelope, deer, cypress, pine, walnut, sycamore, willow and oak. One of a series of Smilodon skulls reveals a replacement saber growing alongside the original tooth. 100 species of insect are represented by beetles and dragonflies looking like Pythonesque delicacies dipped in dark chocolate. There must be a crunchy frog in there someplace (actually, two species of frog and toad each).

Perhaps most remarkable is a suite of bird skeletons. Bird bones are so fragile that they don’t often fossilize well, but the tar has been gentle on them. Stork, pheasant and quail perch alongside turkeys, the most common species. But it’s a batch of raptors that truly dazzles. These include several species of eagle, vulture and condor culminating in the massive Teratornis merriami, a giant condor with a 12 foot wing span. Colorful murals behind the mounts put the meat and feathers back on their bones.

The most memorable exhibit displays 400 of the Page’s 1600 Dire Wolf skulls tacked to a backlit wall in neat columns. They so resemble an artful array of shoes that museum staff call it “Imelda’s Closet” after the famously footwear fetishizing first lady of the Philippines. The carnivore to herbivore ratio among the La Brea discoveries is the inverse of what it would be in life, by some counts as high as 9 to 1 for the bigger critters. That’s because once an initial animal became stuck in the asphalt -- likely lured by surface water -- a multitude of predators and scavengers would convene for an easy meal. Many of these became trapped themselves. Hence the high body count among meat eaters.


    Imelda's Closet Canis dirus; an extinct eagle; the fabulous tar pull.


Not all the Page’s exhibits are fossils. An animatronic dwarf woolly mammoth excites the toddlers while elsewhere a sabertooth sinks its fangs into a hapless sloth. These slightly goofy automatons are mercifully about as Hollywood as the Page gets. Those and a jokey orientation film.

But my heart belongs to an interactive exhibit that promises to reveal “what it’s like to be trapped in tar”. At a hexagonal platform visitors can tug on chrome pistons plunged into gooey asphalt under a plexeglass barrier. The unit’s orange Formica skin belies the facility’s 1970s pedigree. The gift shop used to sell a postcard of models in bellbottoms and Afros enjoying this wonderfully abstract device, but sadly, no more. Was it deemed too retro?

The museum also includes archaeological artifacts like fish hooks and bone tools. People have been using the local tar to waterproof buckets and barrels since they arrived in the area over 9,000 years ago. A law yet on the books entitles Los Angeles residents to collect tar for their personal use. Archival photos depict early excavations while a vividly illustrated time-line puts the extinction of this Ice Age megafauna in perspective. Whether the cause of this great die-off was human predation or climate change, the Page isn’t picking sides.

The fecundity of the Tar Pits has revealed a wealth of data about Ice Age ecology and animal populations. But until recently it hasn’t had much to say about individual creatures. Due to the natural churning of the asphalt, scavenger scattering and other causes, the tar bound bones come disarticulated, anonymous. While the skeletons on display are for the most part actual bones, these mounts are canny composites. The bones did not necessarily come from the same animal, and that diminishes their scientific value. So the discovery of Zed was big news, literally. Zed is the name given to a huge, articulated, near complete Columbian Mammoth skeleton uncovered in 2006. Zed was not buried in tar, but in clay sediments nearby. Not only were most of his bones found in  life position, he sported a full set of tusks, a first for Rancho La Brea. During my May 2009 visit Zed’s pelvis, jaw and a plaster jacketed tusk were on display in the Fishbowl Laboratory where visitors get a generous peek at fossil prep in action.


    Tar puddle bubble; Pit 91; Project 23.


Across the park, visitors can also see a fossil excavation in progress. A viewing platform overlooks Pit 91, hailed as the longest ongoing urban paleontological site in the world (“!”). It’s not always open, and during my visit the dig was on hiatus. But a docent answered questions and pointed out bones emerging from the inky ooze, like a horse scapula, 14 feet below.

Though the lion’s share of the Page’s 3.5 million specimens is booty from  the big digs of 1913-15, the bones, like the tar, keep coming. A recent construction project at neighboring LACMA uncovered a wealth of fresh fossil deposits. Not wanting to halt construction for the years it would take to excavate the new finds an accommodation was reached. The site was carefully gridded out and the strata transferred in massive blocks into “tree boxes”. 23 open crates, like pinewood dumpsters, sit fenced off at the NW corner of the park. Hence the title, Project 23. Scientists and volunteers are now painstakingly picking through these piles one box at a time. At a local gift shop (not associated with the Page) Howard gleefully pointed out a t-shirt that read, “What Happens in the Tar Pits Stays in the Tar Pits”. Seeing the Page folks at work I thought, “Not if these people can help it”.

But big bones aren’t the whole story at La Brea. Since 1969 microfossils – seeds, pollen, bacteria even – have come to the forefront of research, opening an ever wider window on this Ice Age ecosystem. Plant fossils also offer insight into climate change, showing how LA has progressed from a cool and moist to hot and dry environment over the last 40,000 years.

The Tar Pits are just one instance of a wider phenomenon that distinguishes Los Angeles. This megalopolis of 4 million lives cheek by jowl with it’s natural setting like no other big city I can think of. Here the sea abuts the desert over a tectonic fault that sends seismic shivers through the region. Two minor earthquakes  sparked dinner conversation the last week I was there. And though the ground sloths and mammoths are gone, wildlife abounds. Housepets are menaced by coyotes who share the streets with raccoons and opossum. One friend’s home dangles over a parched suburban canyon frequented by owls and bobcats. Squirrels and fence lizards regularly take up residence in her clothes closet. After watching sea lions frolic off Point Dume a fat gopher snake slid lazily across our path. Back at the Page, hummingbirds are a frequent sight whirring around the atrium. They may not be giant teratorns, but to an Eastern city boy, they’re still pretty cool.



A version of this article appeared in the NYPS newsletter, The Spirifer.


 


    American Lion Felis atrox, the wolf wall beyond.