Recent Items about the Late Pleistocene in the News

3 stories relating to the late Pleistocene recently made the mainstream news.  The first story is about the upcoming resurrection of the woolly mammoth (Mammuthus primigenius).  George Church of Harvard University is using CRISPR technology to genetically engineer a woolly mammoth by editing Asian elephant (Elephas maximus) DNA.  (I explained CRISPR technology in a previous blog entry.  See: https://markgelbart.wordpress.com/2016/07/22/possible-resurrection-of-the-mammoth-as-early-as-2018/  ) Scientists at Church’s lab are going to edit in the phenotypical characteristics that make the woolly mammoth able to survive in cold wet climates with extremely short and long days.  These characteristics include a layer of fat, long oily hair, small ears, the ability to withstand cold temperatures, and adjustments to the circadian rhythms animals that live in the Arctic require.  They think they can produce a genetically engineered woolly mammoth by 2019.  Scientists hope to eventually engineer herds of woolly mammoths that can live in Siberia where their activities will convert the tundra landscape into a grassy steppe.  Ecologists believe a grassy steppe environment will better prevent permafrost from melting, thus mitigating anthropogenic global warming.  I’m all in favor of resurrecting herds of woolly mammoths, but I believe their goal of mitigating global warming is a pipe dream, and I doubt woolly mammoths could survive in the present day tundra.  I suspect woolly mammoths were confined to relic steppe habitat during interglacials.  Climate is a much greater influence on sub-Arctic habitat than the activities of megafauna.  Woolly mammoths could probably survive today on the grassy Tibetan steppes but not in the Siberian tundra.  The mammoth steppe of the late Pleistocene was more like the modern Tibetan highlands than the Siberian tundra.

The 2nd story reported the results of a statistical study that determined the average size of mammal species has declined over the past 130,000 years, and the authors of this study squarely blame man.  Humans have been overhunting large mammals that reproduce slowly to extinction, leaving smaller species that can better replenish their populations with faster breeding.  Rabbits breed faster than mammoths and elephants.  The average size of a North American mammal species during the late Pleistocene was 216 pounds compared with the average North American mammal species of today which weighs 16 pounds. This decline in body size is unprecedented over the past 65 million years and hasn’t occurred since the extinction of the dinosaurs.  The fossil record is pronounced…this statistical study just confirms the obvious.

Evidence humans may or may not have tracked a ground sloth in New Mexico is perhaps the most interesting story.  There are thousands of late Pleistocene-aged animal tracks in the White Sands National Monument.  During the Ice Age weather patterns were different due to altered climate cycles, and southwestern North America was much wetter than it is today.  The site of these tracks, presently a desert, was a lake shore then.  The animals walked on the edge of the lake in the mud and the tracks have been preserved for thousands of years.  Scientists found human tracks adjacent and actually within ground sloth tracks.  Ground sloths usually walked in a straight line, but these tracks appear to show the ground sloth zig-zag, as if it was avoiding a predator.  There are 2 sets of human tracks.  One human was directly following the ground sloth–his steps are inside the ground sloth steps; the other human was walking very gently beside the other person, as if on tiptoe.  The ground sloth circled around and appeared to rise up on its legs and bare its claws.  There are claw marks in the ground too.  Scientists suggest 1 human was distracting the ground sloth, while the other was sneaking up on it to deliver a fatal spear thrust or blow to the head with a club.  The end result is not recorded in the tracks.  Other scientists are skeptical of this interpretation.  Some think it unlikely humans would hunt the sloth in such an open landscape.  However, this site was not as open then as it is today, and humans could easily outpace a ground sloth.

Image result for human footprints inside sloth prints

Human footprint inside sloth print.  The sloth print is 22 inches long.  The human footprint is 5 inches.  The sloth had a wider stride, so the human must have been hopping to get his foot inside the sloth’s print.

I wish there were more mainstream news stories about the late Pleistocene.  It’s much more interesting than waiting for Donald Trump to get impeached.

References:

Daley, J.

“Fossil Tracks May Record Ancient Human Hunting Sloth”

Smithsonian April 20, 2018

Smith, F.; et. al.

“Body Size Downgrading of Mammals over the Late Quaternary”

Science  April 2018

One Response to “Recent Items about the Late Pleistocene in the News”

  1. ina puustinen-westerholm Says:

    Possible redesign/introduction..of mammoth by 2019? That news had tippitoed past me..and thanks for bringing it up to the forefront. And hunting anything..for the early folks..is always going to sound reasonable to me. Here..have a haunch of sloth..and, a claw to clean yer teeth..ok? Oh..and the meat around the bones..damn tasty!! 😉

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