Bison at La Brea Tar Pits

I am going to request information from the museum as to the exact numbers and ages of animals found. I'll ask for the numbers of all large mammels. I think this will help. I'll also ask what the error margin is for judging the ages of the bison calves. I'm glad to see that at least some of you can see problems with the clarity of the information given on the sign.

Thanks for asking. I'm still working slowly through that book (Ancient Earth Ancient Skis). It's a bit over my head, but is also raising some questions which I am looking into.

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BTW, do we actually have migrating herds of bison these days?

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Yes, although we try to keep their ranges small.

In case anyone is interested, this is the email I sent to the museum. Hopefully they will provide me with the requested information soon.

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I recently visited your museum with my family. One display about bison migration sparked my interest, and I have been doing some research regarding it. I am having trouble, however, finding some of the desired information. Could you please provide me with the following:

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-The number of bison found in the tar pits divided into the various ages found. (how many 2-4 month olds; how many 14-16 month olds, etc)
-the ratio of male vs. female bison found
-the margin of error in determining the ages of the bison calves
-the numbers and ages of other large mammals found at the Rancho La Brea tar pits

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Thank you very much for your time

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Those are certainly good questions, Christian, but you might get things cleared up more quickly if you just told them the problems that you (and we) have with the sign in the museum. It would be interesting to see if they have a good answer if asked directly.

Yes, it would be interesting to see what their answer would be. I didn't have time today, however to articulate my problem to them, but I did get an answer to my email. Here's what they said:

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I was very pleased to learn that your visit to the Page Museum stimulated your further research into the bison migration story.

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I was not involved in the original research but believe the information you seek may be found in the following publication:

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Jefferson, G. T. and J. Goldin 1989. Seasonal migration of Bison antiquus from Rancho La Brea.
Quaternary Research, 31: 107-112.

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The numbers of the different kinds of large mammal fossils changes annually as our excavation progresses but a summary of the numbers of fossils before our current excavation started may be found in:

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Marcus, L. F. 1960. A census of the abundant large Pleistocene mammals from Rancho La Brea. Contributions in Science No. 38 pp 1-11.

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Kind regards,
John Harris

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I don't have time now to look for the sources he referenced, but maybe one of you want to do that. Perhaps this info will clear up the problem, otherwise I'll send them another email.

I plan to be at the Texas Tech library Saturday doing work-related stuff - I'll look for these papers, too.

cool!You might need to specifically ask for records of non-migratory animals (rather than large ones) to show the seasonal pattern of entrapment in the tarpits and differentiate it from the pattern observed in the bison. Great. If you have trouble with some specific questions there are a number of people here who can help find the leads to the answers ...

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Grandkids are GREAT! The cutest 15-month-old in this half of the state just came by, smiled, and erased version 1 of this post with a single keystroke. I found the Jefferson & Goldin paper, and it clarifies one important point after discussing the same timing issues we've kicked around here: The 1960 Marcus paper is mostly concerned with the differences in trapping in various pits at La Brea. There were 159 B. antiquus, 1646 dire wolves, and 1029 sabre-toothed cats in inventory in the L.A. collection then.

Do either of those papers have the specific information I requested?

What this information (a half century old though) does clue us into is the sample size.If the 159 is the total number of bison found to that point we are probably talking about from 50 to 200 calves total found over some 10,000's of years. (assumes a larger number has been found -say 300 now and there there was a disproportionate number of calves trapped).In other words even though it is true that no calves have been found outside of some very narrow ranges that doesn't mean that calved weren't there outside of those ranges so the issue with calving season lengths isn't such a big deal.However, finding zero outside a narrow range does suggest that they were not there year round. The information above also offers an alternative explanation though: they only get trapped for a few months each year. I think that would show the same pattern.In either case (certainly the second where the tar is only sticky part of the time) removes any single capture as being viable.This message has been edited by NosyNed, 04-23-2006 07:09 PM

Ok, so the sample size is smaller than what I would've thought. I would like to know how many of those were calves and of which ages. Of course a bigger sample would give us more accurate information. With a smaller sample, it's hard to draw any conclusions. I would like to read those papers myself. Hopefully I'll get a chance to do that. I also may ask again for the requested information if it isn't on those papers. It has to be somewhere. My contention is that the information on the sign is still incorrect.

At least the bison age distribution and some discussion of age error brackets are in the Jefferson/Goldin paper, but, with my usual lack of foresight, I failed to read or copy all of it. The part I have does mention that adult females appear to outnumber adult males by 2.5 to 1 - this is based on analysis of horns, so it doesn't apply to juveniles. It also says, with reference to the ages mentioned on this thread, "Juveniles of intermediate ages are very poorly represented in the assemblage."Quaternary Research is a fairly major journal, I'd think, and should be available at most any state university library. If you can't find it, Christian, I'd be glad to copy the rest and send it to you - you'd just have to email me a fax number or address, or be willing to receive a big image file by email.The full name of the other journal is Contributions in Science - Los Angeles County Museum and I thought I got pretty lucky to find that, with issues for many years, too, at Texas Tech. 'Course, they have a pretty active Quaternary research effort there, with Clovis, Badwater Draw, and Yellowhouse Canyon all within a couple of hours' drive.

Thanks Coragyps. I should be able to find it. It's just a matter of finding the time. I'll let you know if I have trouble.