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Author Topic:   Bison at La Brea Tar Pits
Christian
Member (Idle past 6255 days)
Posts: 157
Joined: 10-16-2005


Message 1 of 44 (304298)
04-14-2006 5:47 PM


I recently visited the La Brea Tar Pits with my family. We had a great time and learned a lot. One interesting thing we noticed was the ages of the bison found there. Next to some of their jawbones was a sign that said this:
quote:
Migration
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?
At Rancho La Brea, paleontologists have found fossils of many young bison. They can tell the age of the bison by the number and kind of teeth in the jaw and the amount of wear shown by the teeth. The young bison from the asphalt deposits are either 2 to 4 months old, 14 to 16 months old, or 26 to 30 months old. Each group is thus 12 months (one year) apart. No bison have yet been recovered that are of intermediate ages- 5 to 13 months old or 17 to 25 months old.
These clusters of ages indicate that the bison were present at Rancho La Brea only during a few months of the year. If the calves of extinct bison were born at the same time of the year as modern bison calves, then the bison were present at Rancho La Brea every year during late spring.
My husband and I found it interesting that there were no bison found with ages of 5 to 13 months or with ages of 17 to 25 months. So we did a bit of research. Here's what we discovered:
1. This statement:
quote:
These clusters of ages indicate that the bison were present at Rancho La Brea only during a few months of the year
cannot be true unless all the bison were born on or very near the same day, every year for the 30,000 years represented by the tar pits. If there was any variation (as there is with modern bison) they would've had to move very rapidly through Rancho La Brea staying only a few days at the most. Also they would've had to go through the area during the same few days every year for 30,000 years.
2. This statement:
quote:
If the calves of extinct bison were born at the same time of the year as modern bison calves, then the bison were present at Rancho La Brea every year during late spring.
is false and misleading. Modern bison calves are born mostly in may but can be born any time from mid April through July or August. There were no newborn calves, no one month old calves. If all the calves were born in May, they would've had to go through Rancho La Brea in July, August, or September (mid summer to early fall) even if all the calves were born in April, the earliest they could've traveled through Rancho La Brea would be June . For them to be present at Rancho La Brea during late spring, they would've had to have been born in February or March, which is not when modern bison are born.
3. Their scenario doesn't seem very likely. What seems more likely is that there was some sudden event which killed all those animals, and there were bison ranging from 2-4 months which had been born that year, bison ranging from 14-16 months which had been born last year, and bison ranging from 26-30 months which had been born two years previously.
I would like to point out that I want this to be a very narrow topic. I don't want to be asked to prove how the flood could cause the animals to be trapped in tar. That is not something I have researched. I simply want people to agree with me that a sudden event is more likely if you only consider the ages of the bison babies, and that the scenario given at the museum doesn't adiquately explain what was found.

Replies to this message:
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 Message 9 by DominionSeraph, posted 04-16-2006 10:41 PM Christian has replied
 Message 17 by jar, posted 04-17-2006 12:34 PM Christian has replied
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AdminNosy
Administrator
Posts: 4754
From: Vancouver, BC, Canada
Joined: 11-11-2003


Message 2 of 44 (304304)
04-14-2006 6:07 PM


Thread moved here from the Proposed New Topics forum.

  
NosyNed
Member
Posts: 8996
From: Canada
Joined: 04-04-2003


Message 3 of 44 (304324)
04-14-2006 9:22 PM
Reply to: Message 1 by Christian
04-14-2006 5:47 PM


Alternate explanations.
cannot be true unless all the bison were born on or very near the same day, every year for the 30,000 years represented by the 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?
For them to be present at Rancho La Brea during late spring, they would've had to have been born in February or March, which is not when modern bison are born.
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.
What seems more likely is that there was some sudden event which killed all those animals,
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.
I don't want to be asked to prove how the flood could cause the animals to be trapped in tar. That is not something I have researched.
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

This message is a reply to:
 Message 1 by Christian, posted 04-14-2006 5:47 PM Christian has replied

Replies to this message:
 Message 5 by Christian, posted 04-15-2006 12:46 AM NosyNed has replied

  
Chiroptera
Inactive Member


Message 4 of 44 (304327)
04-14-2006 9:40 PM
Reply to: Message 1 by Christian
04-14-2006 5:47 PM


Hi, Christian.
quote:
What seems more likely is that there was some sudden event which killed all those animals....
Although the tar does pose problems with dating the bones, they have nonetheless been dated -- the deaths span a 44,000 year range, so a single event can be ruled out.
-
quote:
I simply want people to agree with me that a sudden event is more likely if you only consider the ages of the bison babies, and that the scenario given at the museum doesn't adiquately explain what was found.
Unfortunately, we don't have the luxury of only considering the ages of the bison. We have a wealth of other information that needs to be taken into account, such as the dating of the bones, the signs of scavenging of many of the remains, and the lack of good, unambiguous evidence of a catastrophe that would have cause so many deaths in such a short time.

"Religion is the best business to be in. It's the only one where the customers blame themselves for product failure."
-- Ellis Weiner (quoted on the NAiG message board)

This message is a reply to:
 Message 1 by Christian, posted 04-14-2006 5:47 PM Christian has not replied

  
Christian
Member (Idle past 6255 days)
Posts: 157
Joined: 10-16-2005


Message 5 of 44 (304363)
04-15-2006 12:46 AM
Reply to: Message 3 by NosyNed
04-14-2006 9:22 PM


Re: Alternate explanations.
NosyNed writes:
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.
The idea I was trying to portray was that any variation in times of births, would necessitate a shorter stay at Rancho La Brea. If they were born within a couple of weeks (a much shorter span than we see in modern bison) they would only be able to stay at La Brea for 1.5 months max. But the sign says that they stayed a few months. Seems misleading to me.
2) Born over a two month period and arrive at the tar pits at the end of that time period and stay two months.
No. Because there were no newborn and no one month old calves. Also this scenario has them traveling and giving birth at the same time.
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).
Yes but that is not what the sign indicated. The sign indicated that they stayed there for a few months every year. Also they would have to give birth within the same two months and travel through La Brea within the same few days every year for 30,000 years (or 44,000 according to Chiroptera)
What source do you use for the birthing period of bison?
I've looked at several. Here's one:
Requested Page Not Found (404)
That's all the time I have tonight. I am curious about your statement "Not when modern bison are born on the great plains." Do you have a source stating that modern great plains bison are born in Feb. and March?

This message is a reply to:
 Message 3 by NosyNed, posted 04-14-2006 9:22 PM NosyNed has replied

Replies to this message:
 Message 6 by NosyNed, posted 04-15-2006 2:12 AM Christian has replied

  
NosyNed
Member
Posts: 8996
From: Canada
Joined: 04-04-2003


Message 6 of 44 (304370)
04-15-2006 2:12 AM
Reply to: Message 5 by Christian
04-15-2006 12:46 AM


Bison Calving
The idea I was trying to portray was that any variation in times of births, would necessitate a shorter stay at Rancho La Brea. If they were born within a couple of weeks (a much shorter span than we see in modern bison) they would only be able to stay at La Brea for 1.5 months max. But the sign says that they stayed a few months. Seems misleading to me.
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.
No. Because there were no newborn and no one month old calves. Also this scenario has them traveling and giving birth at the same time.
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.
Yes but that is not what the sign indicated. The sign indicated that they stayed there for a few months every year. Also they would have to give birth within the same two months and travel through La Brea within the same few days every year for 30,000 years (or 44,000 according to Chiroptera)
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.
That's all the time I have tonight. I am curious about your statement "Not when modern bison are born on the great plains." Do you have a source stating that modern great plains bison are born in Feb. and March?
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
quote:
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
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.

This message is a reply to:
 Message 5 by Christian, posted 04-15-2006 12:46 AM Christian has replied

Replies to this message:
 Message 7 by Lithodid-Man, posted 04-15-2006 4:24 AM NosyNed has not replied
 Message 13 by Christian, posted 04-17-2006 12:16 PM NosyNed has replied

  
Lithodid-Man
Member (Idle past 2930 days)
Posts: 504
From: Juneau, Alaska, USA
Joined: 03-22-2004


Message 7 of 44 (304377)
04-15-2006 4:24 AM
Reply to: Message 6 by NosyNed
04-15-2006 2:12 AM


Re: Bison Calving
Nosy,
I did find the abstract of the article I assume the poster was based on:
Evidence for annual seasonal migration of extinct Bison antiquus in the late Pleistocene fossil assemblage from Rancho La Brea, California, is demonstrated for the first time. The maturation of individuals from the B. antiquus sample was analyzed using the cheek tooth eruption sequence and occlusal wear patterns in juvenile and young adult inferior dentitions. Individual age of the specimens was established by comparison with wear stages observed in modern B. bison dentitions of known age. Assuming that reproductive behavior was restricted to a specific annual cycle similar to modern B. bison, B. antiquus was seasonally present at Rancho La Brea during the late spring. An annual migratory pattern is indicated by the presence in the assemblage of yearly groups of young individuals of the same age.
Jefferson GT & Goldin JL (1989) Quaternary Research 31(1) 107-112
This is essentially the same as the poster, apparently so no new info. I have requested the full text article via our ILL and will post again when I read it. I also found this article which is available online and cites this paper:
http://tornado.sfsu.edu/.../gm700/PDF_Files/Connin_et_al.pdf
Which seems to support that there were really big differences in rainfall patterns and plant communities seasonally during the Pleistocene of the SW US.
Anyway, I will post again when I read the article...

Doctor Bashir: "Of all the stories you told me, which were true and which weren't?"
Elim Garak: "My dear Doctor, they're all true"
Doctor Bashir: "Even the lies?"
Elim Garak: "Especially the lies"

This message is a reply to:
 Message 6 by NosyNed, posted 04-15-2006 2:12 AM NosyNed has not replied

  
Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 8 of 44 (304420)
04-15-2006 11:59 AM
Reply to: Message 1 by Christian
04-14-2006 5:47 PM


cannot be true unless all the bison were born on or very near the same day, every year for the 30,000 years represented by the tar pits. If there was any variation (as there is with modern bison) they would've had to move very rapidly through Rancho La Brea staying only a few days at the most...
This site tells me that bison mating season starts in July and can run through September. That's a spread of three months. They give birth therefore in Spring/early summer.
We shall say then that birthing starts in April, running through to June. One month later (July) mating season starts again, and one month after that they arrive at the tar pits (in August). This means that the calves that were born in April (the eldest) will be 4 months old; the youngest calves, born in June will be only two months old.
In this case, you are right - if they stayed a few months, we should expect to see 5 and 6 month olds.
However, if birth happened closer to the time of their arrival things might be different. Especially if younger calves are treated differently. I can't find any particular information that would be definitive either way. However, at two months old, the calf begins to develop its horns and humps. I'm also reading that most calves are weaned by late summer. The latest calves to be weaned take seven months, but it seems a few get their earlier.
Perhaps the calves we see in the pits were weaned? We'd need more information to be sure (the nature of the teeth wearing for example).
Alternatively, as Lithoid has said, it could be that we are getting the information worded within error bars (that is, the ages of the calves found are 3 months plus or minus one month).
That said, kudos for have a critical mind and percieving the strangeness of the numbers. We need to look at some primary literature concerning the aging of these bison, so we can establish how the museum have interpreted it for easy consumption.

This message is a reply to:
 Message 1 by Christian, posted 04-14-2006 5:47 PM Christian has not replied

Replies to this message:
 Message 12 by Coragyps, posted 04-17-2006 11:00 AM Modulous has replied

  
DominionSeraph
Member (Idle past 4754 days)
Posts: 365
From: on High
Joined: 01-26-2005


Message 9 of 44 (304679)
04-16-2006 10:41 PM
Reply to: Message 1 by Christian
04-14-2006 5:47 PM


Christian writes:
What seems more likely is that there was some sudden event which killed all those animals
While they just happened to be standing in tar?

This message is a reply to:
 Message 1 by Christian, posted 04-14-2006 5:47 PM Christian has replied

Replies to this message:
 Message 10 by Christian, posted 04-17-2006 10:21 AM DominionSeraph has not replied

  
Christian
Member (Idle past 6255 days)
Posts: 157
Joined: 10-16-2005


Message 10 of 44 (304726)
04-17-2006 10:21 AM
Reply to: Message 9 by DominionSeraph
04-16-2006 10:41 PM


DominionSeraph writes:
While they just happened to be standing in tar?
No, that's not what I think, but I'm not discussing that at this point. I have limited time and have to discuss one thing at a time. Have a nice day.

This message is a reply to:
 Message 9 by DominionSeraph, posted 04-16-2006 10:41 PM DominionSeraph has not replied

  
Yaro
Member (Idle past 6495 days)
Posts: 1797
Joined: 07-12-2003


Message 11 of 44 (304729)
04-17-2006 10:41 AM


Good to see your still around Christian. Glad to hear you visited La Brea
It's a good question you have too, though I don't see how you can get it to fit with your flood theory

Replies to this message:
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Coragyps
Member (Idle past 734 days)
Posts: 5553
From: Snyder, Texas, USA
Joined: 11-12-2002


Message 12 of 44 (304730)
04-17-2006 11:00 AM
Reply to: Message 8 by Modulous
04-15-2006 11:59 AM


Of course, Bison antiquus needn't have had the same breeding season as modern bison - they might have calved in February in Tiajuana, for all we on this board know at this point. I don't really see where the dates are all that odd, and I'll bet that published data exists that clears the phenomenon up.

This message is a reply to:
 Message 8 by Modulous, posted 04-15-2006 11:59 AM Modulous has replied

Replies to this message:
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Christian
Member (Idle past 6255 days)
Posts: 157
Joined: 10-16-2005


Message 13 of 44 (304748)
04-17-2006 12:16 PM
Reply to: Message 6 by NosyNed
04-15-2006 2:12 AM


Re: Bison Calving
NosyNed writes:
However the material is NOT a scientific paper.
So it doesn't have to provide accurate information?
NosyNed writes:
."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.
MY 1.5 month stay? I don't think it's very likely that they stayed for 1.5 months. Bison these days are born over a period of at least 2 months, which wouldn't give them more than a day or two to stay at La Brea each year. And even if they were staying there 1.5 months, their statement would be in disagreement. "A few" generally indicates between 3 and 5.
NosyNed writes:
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.
Even if we assume that all the calves were born in May. There are problems with the statment on the sign. If they were born anytime in May that gives a 1 month span for them to be born. They would have to arrive at La Brea in July (which is not late Spring)They would have to arrive towards the end of July so that the youngest calves (born end of May) would be 2 months old. They could only stay until mid September at the latest, because after that the oldest ones (born beginning of May)would look more like 5 month olds than 4 month olds. That only gives them 1.5 months which is less than "a few" . Notice that I'm allowing for some calves to actually be 4.5 months old. They would have to continue these narrow patterns for many thousands of years. The more year to year variation you allow for, the smaller the window of time for them to be born and the smaller the window of time for them to remain at the tar pits.
NosyNed writes:
You are objecting to some very minor details.
I'm only pointing out that their scenario doesn't work very well, and that their info is misleading and false.
NosyNed writes:
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?
That was you. Message 3
NosyNed writes:
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).
NosyNed writes:
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).
It was yours. And I don't think bison migrating patterns are that precise. They seem to vary from year to year.
NosyNed writes:
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.
Whatever the case, the conditions would have to be almost exactly the same every year for many thousands of years.
NosyNed writes:
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?
Do you know of any modern bison which are born in Feb and March? I agree that ancient bison could've calved earlier, but the sign said:
quote:
If the calves of extinct bison were born at the same time of the year as modern bison calves, then the bison were present at Rancho La Brea every year during late spring.
Which is false.
NosyNed writes:
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.
What they have up there is clearly false. Maybe YOU can provide some information which excuses them from lying to the public?
NosyNed writes:
You are adding "information" of your own that is not there.
What "information" am I adding that's not there?
NosyNed writes:
and then suggesting an alternative that is in no way at all compatible with the available information.
If it's helpful we can just forget my alternative. I'll just stick with pointing out that the museum is posting false information and that their migration scenario seems inadequate given the ages of the animals found.
NosyNed writes:
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.
I hope you're not accusing ME of intelectual dishonesty.
NosyNed writes:
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).
It would be nice to see percentages. Maybe our next field trip should be a bison ranch. this one http://www.nature.org/aboutus/travel/almanac/nea.php?requ... says the babies are born May through July.
NosyNed writes:
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.
Yes, I would like to see that information too. I looked and couldn't find anything. I wonder why it's so hard to get that info?
NosyNed writes:
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.
But it does say
quote:
No bison have yet been recovered that are of intermediate ages- 5 to 13 months old or 17 to 25 months old.

This message is a reply to:
 Message 6 by NosyNed, posted 04-15-2006 2:12 AM NosyNed has replied

Replies to this message:
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Christian
Member (Idle past 6255 days)
Posts: 157
Joined: 10-16-2005


Message 14 of 44 (304753)
04-17-2006 12:25 PM
Reply to: Message 12 by Coragyps
04-17-2006 11:00 AM


Coragyps writes:
Of course, Bison antiquus needn't have had the same breeding season as modern bison - they might have calved in February in Tiajuana, for all we on this board know at this point. I don't really see where the dates are all that odd, and I'll bet that published data exists that clears the phenomenon up.
But then why does the sign say
quote:
If the calves of extinct bison were born at the same time of the year as modern bison calves, then the bison were present at Rancho La Brea every year during late spring.
?
Also I would be very interested to see that published data.
This message has been edited by Christian, 04-17-2006 12:26 PM

This message is a reply to:
 Message 12 by Coragyps, posted 04-17-2006 11:00 AM Coragyps has not replied

  
Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 15 of 44 (304754)
04-17-2006 12:25 PM
Reply to: Message 12 by Coragyps
04-17-2006 11:00 AM


Of course, Bison antiquus needn't have had the same breeding season as modern bison - they might have calved in February in Tiajuana, for all we on this board know at this point.
Quite. The specific dates are not important, but the relative dates are.
I don't really see where the dates are all that odd, and I'll bet that published data exists that clears the phenomenon up.
Assuming there are no other factors involved would seem to suggest Christian was right - however as you say, there are likely other factors not discussed in the brief text presented.

This message is a reply to:
 Message 12 by Coragyps, posted 04-17-2006 11:00 AM Coragyps has not replied

Replies to this message:
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