Bison at La Brea Tar Pits

One can construct several scenarios:1) Born at about the same time ( within a couple of weeks or so --to suggest the accuracy means the same day is silly). Then arrive at the tar pits 2 months after the end of the birthing period and stay for up to 2 months.2) Born over a two month period and arrive at the tar pits at the end of that time period and stay two months.3) Born over a two month period and arrive at the tarpits 2 months later but pass through in a few days or so (migrating through).4) Some mix of those.If those bison were born "mostly in May" but can be born spread over 4 months (April to August) we'd have to know the percentages outside of a 2 month period of, say May and June. Then we could calculate the number of younger (or a bit older if the age determination is precise enough) that we should expect to find assuming that the entrapment is random with respect to age. (The very young may stay with the mother more closely and be protected by their weariness for example.)What source do you use for the birthing period of bison? Not when modern bison are born on the great plains. How close was the Rancho la Brea climate to todays Meditterean climate at that time? You have some assumptions that need to be supported or researched. As noted, these animals did NOT all die at the same time but rather died over an extended period of 1,000s of years. That is, all by itself enough to falsify a single incident idea. Of course you don't. It is patently absurd to suggest that it could have.This message has been edited by NosyNed, 04-14-2006 09:22 PM

Good point regarding the ages. However the material is NOT a scientific paper."This pattern indicates that bison were at Rancho La Brea for only a few months at a time." isn't in particular disagreement with your 1.5 month stay based on calf ages.The paper you referenced has (during one study year) "most" (whatever that means of the calves born in the first half of May. There are "occasional" calves born in late summer. The capture in the pits could miss an "occasional" calf. True. The scenario only works if something we don't know from the available information is going on. Do very young calfs get trapped less often than ones wandering from their mother? Do migrating bison keep moving while giving birth? (many animals of this type do so).You are objecting to some very minor details. The age measurements are not down to a few days. The time there is only accurate to a part of a season. Where did you get "same few days" from?Migrating animals in Africa move based on seasonal changes with a degree of precision that matches the precision of the La Brea information. (the 'few days' is yours).Something I don't know is whether the tar pits are particularly dangerous at one time of the year and not another. In the spring they may be water covered but not later in the summer. This would mean the captured animals are not a random sample. What I was saying was that I agree that modern plains bison are NOT born in Feb. and March. Why does that mean that a mirgrating coastal (perhaps Meditteranean climate) population could not birth earlier?The material you are referging to seems to be reasonable given the level of detail we have supplied. You will have to go back to the paleontological data from which it is derived if you want to suggest that it is misrepresenting the data.The explanation for the pattern found in the recovered La Brea fossils is reasonably consistent with the information available. You are working from an enormously summarised "poster" in a museum display. You are adding "information" of your own that is not there. You are nit-picking the explanation supplied and then suggesting an alternative that is in no way at all compatible with the available information.That is exactly the kind of behavior that many creationist web sites get up to. It is precisely that kind of special pleading that is rampant among those who wish to be called creation "scientists". They only demonstrate a complete lack of intellectual honesty.Personally, I don't think the available information totally explains the pattern of calf ages either. I'd really like to see a much greater level of detail. However, I couldn't find it.The facts that I do see from the La Brea site and the paper you referenced are that bison may well produce "most" (I want to know what % this is) of their calves in a two week period. Some calves may be born outside of this range. The calves in La Brea are all within a couple of month range. (see below).That is all we have. We do not know how many bison and calves have been found in the pits. We do not know the climate at the time of entrapment. We do not know the actual expected precision of the ages.Again, what we know fits with the explanation at the level of precision you would expect from a museum display. The explanation that you seem to suggest doesn't fit AT ALL.** age of calves

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By examining the bison jaws for the presence of baby and permanent teeth, paleontologists concluded that all the bison found were either 2-4 months old, 14-16 months old, or 26-30 months old

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This does not give accuracy of these ages. It may actually be the end points of error bars with most of the animals ages concentrated at 3, 15 etc months. We don't know from the available information.

I agree that with what information we have it doesn't work out. I suggest that characterizing it as "misleading and false" is a bit premature. We don't know enough to know what they started with before creating a very, very short summary with simplifications for a museum display. It does appear that they didn't do that well enough but we don't know yet. Not exactly the same. Only to within the accuracy of the age measurements. Not exactly the same only enough that the great preponderance of the captured calves fit the ranges. The captured calves are given as varying over a 4 month range of ages. That is pretty wide. We don't know if there was a variation in the range of captured age with date of capture either.The museum sign all by itself doesn't hang together very well. We don't know enough to determine what is wrong. You are jumping to conclusions.If calves were born at the same time as modern bison (April to August?) then calves under 5 months old (only, and year increments above that) do indicate that they were there during late spring. It also suggests that they must have been there during other times later in the year too but the sign is messed up enough to be unclear. I was mistaken on this. Sorry. No I am not. Only if you attempt to use confusion of a simplified museum sign to hint that the flood is a reasonable explanation. You haven't been clear if you have or not. You did mention a single event, that is clearly out of the question. I think we both agree that the topic here is the quality of information presented at the museum and NOT any other explanation for the pattern found. We'll leave that alone. Yes, but that doesn't tell us how those ranges are determined. Are the found fossils aged to within +- 1 week and measured to be between 0 and 4.5 months or +- 2 months and measured to be about 2 months old? Measurements based on wear would indicate something like the former (but not as tight as one week I wouldn't think), measurements based on development of the teeth or skeleton might indicate something more like the latter.

From here: http://www.nhm.org/cats/C24/bison.htm

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The extinct ancient bison (Bison antiquus) was an ancestor of the living North American bison (often called the buffalo). It is the most common of the large herbivores found at Rancho La Brea. A second, rarer species is the long-horned bison. This had a horn core spread of about six feet (1.8 meters). Bison are thought to have come into North America from Asia about 500,000 years ago across a land bridge that connected Alaska with Asia when sea levels were lower.

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Not all the animals lived at Rancho La Brea year-round. Some were migratory, traveling in and out of the area. How do scientists know this?

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At Rancho La Brea, paleontologists have found fossils of many young bison. They can tell the age of the bison by the number of teeth, baby and permanent, in the jaw and by the amount of wear shown by the teeth. Young bison from the asphalt deposits are either two to four months old, fourteen to sixteen months old, or twenty-six to thirty months old. Each group is thus twelve months (one year) apart. No bison have yet been recovered that are of intermediate ages, five to thirteen months old or seventeen to twenty-five months old.

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These clusters of ages indicate the bison were present at Rancho La Brea onIy during a few months of the year. If the calves of extinct bison were born at the same time of year as modern bison calves, then the extinct bison were present at Rancho La Brea every year during late spring.

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That looks about right for the kind of thing one might see in a museum.So here is what I understand the problem to be:
1) Calves born at the same time of year as modern bison means born from april through july or even august with "most" born in the first half of May.The oldest would be born then 2 months before the end of spring. Therefore the wording "were present at Rancho La Brea every year during late spring" can not be right if they are from 2 to 4 months old. It would be correct if they arrived in late spring.However, if it is the oldest that arrive there at two months old in "late spring" then there should be ones found all the way down to new born but it says they aren't.The second problem is it says there were there "a few months" of the year. But the age ranges are only 2 months and some people don't consider a "couple" of months to be "a few".So given the quote from the web site we have a problem making it precisely correct.Shall I try to write something which is correct? If the bison migrated through they can't take longer than 2 months since that is the full range of calf fossils found -- this is not a "few months" so it should be worked a "couple of months".Assuming that a LOT of calves are captured in the tar so that ALL actual age ranges are represented: If they are born the same time as modern bison then they can't arrive until 2 months after NO more calves are born and captured. But that means that the oldest would be more than 4 months (since modern bison are claimed to calve over a period that is longer than 2 months) so the two assumptions cannot be true. Either we are getting a non-representative sample or the bison calved over a shorter period of time than the one we assume is good for modern bison.The "facts" are supposed to be:
1) born in the same pattern as modern bison which are taken as being over about a 4 month period from late April.
2) None found outside of the 2 month to 4 month (+ 1 year increments) age ranges.
3) arrive in "late spring"
4) stay a "few months"I can't construct a sign which makes sense given the above. Can you?Maybe I should email this? I'll wait for Christian in case he wants to do it or word it.
So I can't make a sign up that presents the same "facts"

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.

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