Mammoth trap

One of the places we visited in the Black Hills was the Mammoth Site, a sinkhole that trapped a number of mammoths over the years. This has the largest concentration of mammoths in the world, and they think they've only dug about a third of the way down. Pay them a visit if you're in the area.

The mammoths seem to have fallen in and drowned, so the scientists think the sides were steep and covered with vegetation, making them a little more enticing in the winter. So far every last mammoth has been male. Maybe, as with elephants, the young males are chased out of the herd to fend on their own and find their own females. And, all alone, you don't get the benefit of other's experience or much help when you get stuck.

Right now they think the sinkhole (spring-fed) is about 140,000 years old, and only finished filling in relatively recently. During our wandering about the pit, I looked at the layers in the sediment and did some back of the envelope estimations. There aren't enough layers for 140,000 individual years, but if the layers represent extra wash from El Nino's (or Nina's, dunno which would send extra water to South Dakota during the various glacial periods), it kind of works out if the average time between Nino's is about 5 years.

It sounds like the place must have been a terrible trap, but if the number of mammoths yet undiscovered is proportional to the number found so far, the hole claimed only about 1 mammoth per thousand years or so. (And a few other critters as well.) So it didn't make much of a dent in mammoth numbers. Could be that most of the time there was an easy way out.

They found a few tiny fish bones--those probably don't preserve very well. The mammoth bones aren't fossils, and all DNA was washed out of them ages ago. Look but don't touch.