Bones belonging to sloth and ancient bison found during Crenshaw/LAX Line work

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The bison bone found recently at left, a sample bison bone at right.
Ancient bison. Credit: La Brea Tar Pits.
Sample sloth bone at left, sloth bone found at right.
Harlan’s ground sloth. Credit: La Brea Tar Pits.

We Found Bones!

Quick Facts:

• Bones were found 16 feet below Crenshaw Boulevard, between 63rd Street and Hyde Park Boulevard.
• One bone is a fragment of a bison.
• One bone is a sloth’s hip joint (Yes, a sloth’s hip!).

More Details:

On May 16th, two partial large mammal bones were discovered in a sandy clay layer area 16 feet under Crenshaw Boulevard. The recovered fossil bones were stabilized and prepared in the Paleo Solutions laboratory and were identified on May 24th with the help of Gary Takeuchi at the La Brea Tar Pits and Museum.

The first fossil was determined to be a bison right proximal radius and the second fossil is identified as a sloth proximal femur head fragment. The fossils will be held at the Paleo Solutions laboratory and will eventually be transferred to the Natural History Museum of Los Angeles County or other accredited repository for permanent curation.

This is an amazing discovery. If this is a Harlan’s Ground Sloth (the largest and most common of three species of ground sloth found at the Tar Pits) then the animal could have easily weighed up to 1,500 pounds and measured up to 10 feet in length.

Although it is difficult to find out all of our Sloth’s history from just one bone, there is some information that can be gathered from our staff’s visit to the Tar Pits. Assuming the sediments are the same age as the Tar Pits, the Harlan’s Ground Sloth (Paramylodon Harlani) lived in the Los Angeles basin 40,000 to 11,000 years ago, i.e. the late Pleistocene era.

Many large mammals that lived in our region — including sloths, bison, ancient camels, mastodons and mammoths — went extinct in North America at least 10,000 years ago during a wave of large animal extinctions following the last Ice Age. Earlier this year, bones belonging to an ancient camel and a mastodon or mammoth were found during excavation work under Wilshire Boulevard for the Purple Line Extension subway.

 

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10 replies ›

  8. Fascinating! Are these fossils discovered by the TBM, or while using other excavation techniques? Is the TBM able to recognize fossils when it encounters them, or does it just gobble up everything in its path regardless of the archaeological or historical significance?

    • I’m kind of interested in this too. I’m guessing it must go slow enough to identify and stop it for things of this nature?