Hi, I’m Chris, and I’ll be your guide on this tour of the marvelous Rancholabrean Pinole Creek scene in the banner painting, brought to us by the fantabulous time machine of the wonderful Carl Buell. Please keep your arms and heads inside the blog as we get going. Thank you.
First things first. The thing to keep in mind about Pinole Creek in this part of the Rancholabrean (late Pleistocene) is that much of the planet’s water is locked up in gigantic ice sheets covering Eurasia, North America, and Antarctica, and the ocean only comes up to 150 feet below year 2007 sea level. Sea level changed dramatically during the Pleistocene: 100,000 years ago or so, there were oyster beds living in shallow salt water about three miles past those bison on the right. But right now, San Pablo Bay isn’t there. Nor is San Francisco Bay, and the Gulf of the Farallones, out the other side of the Golden Gate, is actually the Farallon Plain, a Pleistocene coastal Californian Serengeti with camels and elephants and horses and other strange animals, some of which you are about to meet close up. But don’t worry! We’re equipped with the latest in tranquilizer gun technology.
In the far background, the hills in places that will eventually be called Sonoma, Marin, and Napa counties turn blue in afternoon sun. There is probably a high fog coming in off the Pacific. In front of them, weaving through the broad basin between the Hayward/Rodgers Creek and Calaveras faults that will become San Pablo Bay, is the California River, carrying the combined flow of the Sacramento and San Joaquin rivers westward toward the foothills of Mount Tamalpais, then south toward Raccoon Strait between Tiburon and Angel (will be an) Island (someday), through a river canyon break in the coast ranges that’s now called the Golden Gate, and out across the Farallon Plain anywhere from 12 to 30 miles to the Pacific.
In left foreground, Paramylodon, a giant ground sloth in the Mylodontidae family about six feet from nose to rump, looks for some leafy green vegetables to eat. She is not especially closely related to Nothrotheriops, CRN’s other patron sloth. As a Megatherian, Nothrotheriops is actually more closely related to two-toed sloths of the current day than it is to Paramylodon.
A few dozen yards downhill from the ground sloth, you’ll see a group of teratorns, like condors but with 12-foot wingspans. Teratorns are thought by some scientists to be a possible living basis for the thunderbird myths. These big birds are eating some recently dead megafaunum. I can’t really see what it is from here. It could be anything from part of a Columbian mammoth to another ground sloth, a horse or a tapir (though it’d have to be a big tapir) or a grizzly, perhaps even a saber-tooth cat or short-faced bear. Teratorns, which were big enough and (it is thought) predatory enough to have taken live rabbits and small children, probably played an important role is opening up megafaunal carrion for other scavengers, such as condors, vultures, and ravens— so now we know what that raven is circling around waiting for. Another teratorn is coming in for a landing. Just think: each of those wings is longer than most of you are tall.
In the distance is a coniferous forest, most likely composed primarily of coast redwood and coastal Douglas fir, or at least a very close relation of the latter. There are probably some pines in there as well, likely some relations of the closed-cone pines like the Monterey or Bishop pines. The broad-leaved trees at the ecotone of forest and grazer-wallower-trampler grassland might include alder and elder, Baccharis and oak and tanoak. Looks like it’s been a while since the mammoths have eaten here. Maybe there are more tempting pickings down by the river: looks pretty trampled down there toward what will eventually become Rodeo and Vallejo.
On our side of Pleistocene Pinole Creek, a coyote, Canis latrans, peers through the creek’s fringing willows and tules at the dining teratorns. Or wait a minute: maybe that’s Zeke. No, the fur’s too dark, and besides Zeke’s tail would be firmly tucked between his legs with all these megafauna around. Coyote should be careful, too: she might be the top predator in the biologically depauperate urban Holocene, but right now there are lots of meat-eaters bigger, stronger, and hungrier than she is. If modern-day Yellowstone is any indication, wolves have a thing for killing coyotes: reintroduction of the wolves to Yellowstone has seriously depressed the coyote population, and you can probably interpret that in the population dynamics and psychological senses both. And along Rancholabrean Pinole Creek, coyote not only has to contend with the gray wolves we know, but also with the seven-foot-long, 200-pound dire wolf, Canis dirus, the biggest Big Dog ever. Now some paleontologists think that due to Canis dirus’ bone structure, which was theoretically ill-suited for cursorial hunting, the dire wolves may have functioned more as scavengers and opportunistic hunters rather than gray-wolf-style pack hunters. Still. Seven feet long and two hundred pounds? Cave canem. If that’s not enough, there are still those previously mentioned saber-tooths and short-faced bears. They likely preferred bigger game than the coyote, but why take the risk? Watch your butt, Coyote.
And in the right middle distance, those bison are… well, they’re a calendar, for one thing, something a weary time-traveler could use to get her bearings. Birders distinguish among seemingly identical birds by taking range into account, remembering that species A lives nearby while species B is only found four hundred miles away and then only by fluke. These bison call that to mind, except that the range difference is a temporal one. If this is more than 22,000 years ago, those are Bison latifrons. Less than that, they’re Bison antiquus. Bison latifrons is otherwise known as the “long-horned bison,” due to its really long, dramatically arching horns. Those bison down the hill there look to have shorter horns, so that makes them Bison antiquus, which means we’re at 22KYA or later, really rather close to the Holocene in geological terms. Better enjoy this scene before we pave it.
And of course right up there in the foreground is a raven, Corvus corax, a representation of which species I have learned better than to try to run a blog without.
I hope you’ve enjoyed this tour of Rancholabrean Pinole Creek as much as I’ve enjoyed touring it to you. If you’ll all just make sure your harnesses are secure, our captain will set a course back to your homes in the year 2035, in the glorious waning years of the Jenna Bush administration, where you can… what? I’m sorry, there must be some mixup. Aren’t you with the Iraq-Iran-Syria-Turkey-France war veterans group? Damn. Well, no worries: you can fill out the relocation forms at our office, which you can reach by heading through our fabulous gift shop. Buh-buy, now. Buh-buy.
And thanks, Carl.
Posted by: Chris Clarke
Categories:
The Creek
Paleontology
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