Science Friday

‘Prehistoric Planet’ Defrosts Strange Animals Of The Ice Age

December 23, 2025

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  • Recreating familiar Ice Age megafauna like mammoths and saber-toothed cats presents a greater CGI challenge than obscure animals because audiences immediately notice inaccuracies in well-known forms. 
  • The Ice Age (Pleistocene) was characterized by a drier atmosphere and lower sea levels, leading to expanded deserts and savannahs alongside the familiar cold regions, and featured animals adapted for both extreme cold and dry climates. 
  • The end of the Ice Age extinction event, which wiped out over two-thirds of large mammals, was likely caused by a combination of human impacts, including hunting and the widespread use of fire to transform ecosystems, intersecting with significant climate change. 

Segments

Ice Age Animals CGI Challenge
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(00:02:11)
  • Key Takeaway: Familiar Ice Age animals are harder to reconstruct accurately in CGI than dinosaurs because audience familiarity demands perfect realism.
  • Summary: Dr. Darren Naish noted that recreating familiar Ice Age animals like mammoths and saber-toothed cats is a formidable challenge because any slight inaccuracy fails the ‘sniff test’ compared to remote creatures like tyrannosaurs. This required extremely close collaboration with the CG animators at FrameStore. The season also covers obscure creatures like giant marsupials and sloths, where experts have competing ideas on their appearance and behavior.
La Brea Tar Pits Fauna
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(00:04:40)
  • Key Takeaway: Los Angeles during the Ice Age supported a lush savanna ecosystem featuring seven species of cats, including the American lion, and multiple species of giant ground sloths.
  • Summary: The La Brea Tar Pits preserve thousands of Ice Age animals, indicating that Ice Age Los Angeles was cooler and wetter than today. The ecosystem included the American lion, the largest cat ever, multiple saber-toothed cats, dire wolves, mammoths, and mastodons. The site also preserves hundreds of species of birds, reptiles, and amphibians that still live in the LA basin today.
Ice Age Climate and Adaptations
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(00:05:59)
  • Key Takeaway: The Ice Age (Pleistocene) featured a far drier atmosphere due to water locked in ice sheets, leading to larger deserts and savannahs alongside cold zones.
  • Summary: The Ice Age, or Pleistocene, was a two-million-year period where polar regions were colder, but tropical and subtropical zones were generally drier due to lower atmospheric water content. Animals in cold regions developed thick coats and fat layers, while tropical animals adapted to dryness, sometimes with unusual noses to conserve water. Since the Ice Age ended only 11,700 years ago, nearly all modern species were alive during that time.
Cave Art Informing Reconstruction
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(00:07:54)
  • Key Takeaway: Ice Age cave paintings provided crucial, otherwise unknown information regarding the pigmentation patterns, fur length, and even posture of extinct animals like mammoths and rhinos.
  • Summary: Cave artists, who were skilled illustrators, depicted animals they saw alive, offering data on pigmentation distribution like spots and stripes. This information helped the VFX team determine which parts of animals were dark or light and provided clues about fur length. The art even offered insights into posture, such as when a woolly rhino might hold its tail in the air.
Ice Age Climate Diversity
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(00:08:59)
  • Key Takeaway: The Ice Age was not uniformly cold; warm interglacial periods allowed tropical animals like hippos and lions to inhabit regions like Southern England.
  • Summary: The span termed the Ice Age included multiple warm spells (interglacials) where areas considered cool today were warmer and drier. During these times, animals typically associated with tropical Asia or Africa, such as giant elephants, hippos, and lions, lived in places like England. The diversity of megafauna during the Ice Age suggests that the planet’s current view of large animal diversity is significantly impoverished.
Global Distribution and Migration
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(00:11:10)
  • Key Takeaway: Lower sea levels during the Ice Age created land bridges, such as Beringia, facilitating wide global dispersal for species like lions, which were found across Asia, Europe, and North America.
  • Summary: Many Ice Age species were widely distributed globally, unlike today where they are confined to specific regions; lions, for example, were found across North America, Asia, and Europe. Land bridges formed by lower sea levels allowed these migrations, with Beringia connecting Alaska and Siberia being a prime example. Species like camels originated in North America before crossing into Eurasia and South America, later going extinct in their continent of origin.
Causes of Megafaunal Extinction
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(00:14:35)
  • Key Takeaway: The extinction of large mammals at the end of the Ice Age involved a complex interplay between climate stress and the growing technological impact of Homo sapiens, including hunting and landscape alteration via fire.
  • Summary: The extinction event that ended the Ice Age involved the systematic replacement of large mammals by Homo sapiens over the last 50,000 years. While direct hunting is evidenced for some species like mammoths, it does not account for all extinctions. Research at the La Brea Tar Pits suggests a massive increase in landscape fire, likely ignited by humans, coincided with the disappearance of large trapped animals, indicating fire was a key ecological transformation tool.
Modern Ice Age Research Advances
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(00:17:27)
  • Key Takeaway: Current Ice Age studies are in a golden age, driven by new DNA analysis revealing adaptations like woolly mammoths lacking specific cold-sensing genes, and the discovery of well-preserved permafrost bodies.
  • Summary: DNA studies are providing new insights into animal relationships and adaptations, such as discovering woolly mammoths were genetically adapted to cold, lacking genes related to feeling cold. Global warming is paradoxically aiding research by exposing more beautifully preserved Ice Age animals in Siberian and Alaskan permafrost annually. These discoveries provide extensive information on what the animals actually looked like.