Bison at La Brea Tar Pits

I see no problem with the sign. Perhaps someone could explain the difficulty more clearly? To merit charges of misleading and false, I would have expected the problem to leap off the page.The museum's web site tells us that the climate in the area was cooler and more humid (more like San Francisco at present), and that the warmer months were the most dangerous because the asphalt was softer and more likely to be concealed by leaves and other debris.In particular, I don't understand the notion that the bison would have had to migrate/calve at almost exactly the same day each year for thousands of years, given that the age ranges are months. Since the key data were the relative annual age clusters, what difference does it make which day they were calved? Even if the climate, migratory schedule, or birthing season varied considerably over the millennia, the variance between one year and the next would likely be low.According to the museum, just 10 large mammals being captured every ten years would account for the total mammal assemblage found: how many were bison? How long did bison capture continue? I bet the researchers at La Brea are thrilled each time a school child e-mails them with that kind of question, though I guess it's easier for adults to call them liars.Perhaps someone can help me out here. I don't see anything dishonest, misleading, contradictory, or inadequate about the sign. It presents a bite-sized nugget of scientific hypothesis and is intended to make one ask questions and want to learn more. Christian's OP and subsequent posts are quite ad hoc, but that is a function of intellectual bias, or incompetence, not dishonesty.

Thanks, Nosy. I see the "problem" better now.It's a tempest in a tarpit.Bison, which are migratory animals, were present at La Brea for at least two months of the year, given the ages of the youngest calves captured: possibly, given the age clumping range, they could have been there four months each year.Given the calving habits of modern bison--and the seasonal nature of the tarpit hazard--we can conclude the bison were present at La Brea in late spring when the hazard began to increase due to temperature. The bison left the area before any new calves had aged more than four months.So if they arrived in April with some immediate calving ocurring, with most calving in May, and with the hazard increasing in June and peaking in July, just when the bison might seeker greener, cooler pastures (just as an example motivator--the captured large mammals also attracted predators the bison might want to avoid)...they would be there a few months, calves 2-4 months could be captured, and none older. As to finding newborns in the tarpit, IIRC, few large mammals have precocial young, and as I specifically recall, bison herds organize with cows and calves to the center, bulls protectively at the perimeter; the newborns who felt footloose were unlikely to survive long in the land of the direwolf and short-face bear.Doesn't that work?BTW, do we actually have migrating herds of bison these days?