At Sonoma County State Beach, just south of the mouth of the Russian River, stand two seastack rock pillars surrounded by large boulders. The prominent blue schist rocks form something like an amphitheater above the coastal cliffs.

There is something about these rocks that draws you in. Maybe it's the way they jut out of the ground? Or perhaps it's the "Stonehenge" way they form an enclosed circle? Or maybe it's just a nice place to get out of the wind? Whatever it is, they seem to pull you towards them. And once you are there, they almost call out to be touched. The rocks, long known as the "Sunset Boulders", have attracted rock climbers for years. I've climbed these rocks before. But like so many other people, I had no idea I was touching history.

During the Pleistocene, 10 to 20,000 years ago, this place was very different than it is today, inhabited by massive mega-fauna; bigger elephants, lions, bears and wolves, than we see today. While those big animals went extinct thousands of years ago, they left their mark on this place.

Looking around these rocks it is easy for me to imagine the herds of Columbian Mammoths lumbering from the nearby wallow to rub against the boulders. I can picture huge herds of camel and horse grazing nearby. Yes, those animals evolved here in North America and then crossed into Asia where they thrived and survived. Weaving my way between the boulders, I can imagine how the predators could have used these rocks as an ambush site. I envision a huge saber-tooth cat slinking between the craggy rocks, looking to pounce on an unwary bison. I can see the prides of American Lion, similar but much larger than African Lions, basking on the tabletop boulders after a big kill. I can also picture the ultimate predator making their campsite here when that first hunting party foraged deeper inland. Yes, humans were here too. And I'm sure the same pull these rocks have today existed back then.

This seems like a sacred place to me. Sacred to history. So when you visit these rocks think about those who came before you. Think about the mammoth and the bison and the camel and the horse. Think about the lions, tigers, bears and wolves. And think about those first people. Tread lightly and respect this wonderful place. With care, these rocks will be here long after we all become part of history.

Special thanks to the San Diego Natural History Museum for contributing artwork and HD video to our story. Also, to see more artistic representations of Pleistocene mega fauna, by the artists who contributed to our segment, see:

Laura Cunningham's artwork

Artwork of Joseph Venus

William Stout's wonderful murals

Watch the Ice Age Bay Area television story online.

I had always thought that bringing back an extinct animal like the mammoth was impossible using today's techniques. I may have been wrong.

Maybe a clone of this guy will wander the Earth one day.A new study shows that scientists can clone a mouse that has been dead and frozen for 16 years. If they can apply what they've learned to a mammoth that has been dead and frozen for over 10,000 years, then maybe my kids can ride a mammoth one day. Or at least my grandkids can.

You Need More than DNA to Clone

Cloning isn't as simple as was shown in Jurassic Park. You can't take DNA and make a clone from it. Instead, you need an intact nucleus. And ideally, an intact nucleus in an intact cell.

The nucleus is where DNA is kept in our cells. The DNA is stored and packaged there in a way that only Mother Nature can do (for now). We can’t take our 6 feet of DNA and cram it into the tiny space of the nucleus.

Cloning 101.As I said, right now cloning uses intact cells. Here's how it works:

1) Take a cell from the animal to be cloned
2) Remove the nucleus from an egg (this is called an enucleated egg)
3) Fuse the two cells and let it divide a few times in a Petri dish
4) Implant the growing embryo into a surrogate mother
5) If everything goes well, a clone is born

This procedure requires living intact cells to be used. The problem with a frozen animal cell is that it is dead and ice crystals have torn it apart. It is not possible to fuse a beat up dead cell with an enucleated egg.

Cloning Using Frozen Cells

What the researchers in this new study did was change the protocol a bit. Instead of fusing two cells, they harvested nuclei from the frozen cells and injected them directly into the enucleated egg.

When they tried to clone the mouse that had been frozen for 16 years this way, it didn't work. But they managed to get 4 clones by adding an extra step. What they did was to make embryonic stem (ES) cells from the frozen mouse and use those cells to make a clone.

Basically they cloned the mouse but then instead of putting the embryo into a surrogate mother, they harvested its ES cells. Then they used the nuclei from these cells to create a clone in the usual way.

So we can now clone a long frozen mouse. The next step will be to try to clone an extinct animal like a mammoth.

Cloning a Mammoth is Trickier than a Mouse

Mammoth cloning will be no walk in the park. First off, we don’t have any mammoth eggs or cells to use. We'll have to use elephant ones. Hopefully, elephant eggs and/or cells will be compatible with a mammoth's nucleus. ( But there is some concern they they might not be compatible.)

Second, elephants are a lot harder to work with than mice. The experiments in this study used thousands of eggs to get a few clones. I don’t know enough about elephant biology but it seems like you'd need a lot of elephants to get that many eggs.

But this is definitely the first step in resurrecting long dead animals. For now we'll have to focus on the frozen ones. Maybe in the future researchers can figure out how to clone animals stored in formaldehyde. Or from pelts. Then we can start reviving species we humans have managed to kill off over the years.