Over the years, archaeologists have excavated an abundance of important fossils from the La Brea Tar Pits, also known as Rancho La Brea. How knowledgeable are you about this prehistoric place of many a mammoth's demise?
The La Brea Tar Pits are situated in the heart of Los Angeles. You can find them in Hancock Park, adjacent to the Miracle Mile.
The fossils from the last Ice Age that have been excavated from the La Brea Tar Pits range from around 10,000 to 40,000 years old. Animals still occasionally become entrapped in the pits, however, especially when the weather is warm.
More than 1 million fossilized bones have been pulled from the tar pits, along with the remains of about 150 species of plants and 230 species of invertebrates. All told, the museum collection currently contains more than 3 million specimens, although ongoing excavations constantly push that number higher.
Dire wolves are the most commonly recovered species of large mammal from the tar pits. Currently, the remains of several thousand dire wolves are included in the museum's collection.
Saber-toothed cats are the second-most-common species to come out of the ground in La Brea. Currently about 2,000 individual specimens have been unearthed.
The tar in the La Brea Tar Pits comes up from a nearby petroleum reservoir known as the Salt Lake Oil Field, and it's technically asphalt, not tar. As the petroleum seeps up along fault lines and layers of porous rocks, lighter components of the petroleum evaporate, leaving the asphalt behind.
It's commonly believed that a vicious cycle has played out at the pits over the millennia. The tar pits are often concealed by water, leaves, twigs and other debris, so it's easy for prey animals to accidently become ensnared. Predators and scavengers would have frequently been lured in by the promise of an easy meal, only to find themselves trapped in turn.
Little animals, plants and other organisms would have stood the smallest chance of escaping, as well as larger animals who were injured or ill. As for the others, considerations such as the depth of the tar and the temperature of the air would have been mitigating factors. Deeper tar and warmer temperatures would have made the sticky asphalt much harder to escape from.
Considering how many fossils have been found at La Brea, it might seem like a death trap sucking in living creatures left and right. But considering the pits were at peak activity for some 30,000 years, they had a lot of time to end up filled with fossils. If a large mammal was trapped once every 10 years, for example, and it lured nine more large mammals in with it, that would cover the current number of specimens uncovered.
Project 23 is an excavation assignment that kicked off in 2008 after new fossil deposits were found during the construction of a nearby underground parking garage. Instead of holding up construction for the duration of the lengthy dig, the deposits discovered in 2006 were carefully boxed up as-is into 23 separate boxes, so paleontologists could sift through the contents at their own pace. A crane lifted each box to a waiting truck, which then transported them to their new home in Hancock Park.
The heaviest of the boxes weighed in at a little shy of 125,000 pounds (which is about 55,000 kilograms). They ranged in size from a work bench to a delivery truck.
The whole process of unearthing the deposits for excavation in Project 23, and preparing them for the move, only took about three-and-a-half months.
Pit wear (which comes from bones rubbing against each other) has been noticed more in some of the Project 23 deposits than is usually expected. On top of that, invertebrate and plants fossils are being found in greater concentrations, too.
Zed is a Columbian mammoth discovered during the course of Project 23. Apart from being remarkably intact and sporting the most well-preserved set of mammoth tusks found to date at La Brea, he's also the biggest mammoth ever unearthed there.
Project 23, which is drawing specimens from 16 new deposit sites, is expected to increase the museum's collection two-fold.
The asphalt in the pits was formed over millions of years when the area now known as Rancho La Brea was submerged under the Pacific Ocean. Ancient marine life and sediments layered the ocean floor and were eventually converted into petroleum, also called crude oil.
Despite the extreme conditions -- little-to-no air or water, toxic chemicals and hard-to-crack hydrocarbons -- bacteria in the asphalt of the tar pits are able to work as a community, and some expel methane to the surface as bubbles.
George Allan Hancock inherited the land where his namesake 23-acre park is located to this day.
The money for the actual facilities in Hancock Park was donated by George C. Page. The George C. Page Museum of La Brea Discoveries opened in 1977.
In its first 10 years of operation, the Page Museum received about 5 million visitors, eager to see the exhibits of mammoths, dire wolves and more.