The Miocene, which began 23 million years ago, was the last truly warm period before the onset of the great glaciers. The mastodon family split from the emerging elephant one in Africa some 22 million years ago. By 11 million years ago, the Mammut genus had crossed to North America. Mammoths separated from Asian and African elephants around 6 million years ago, just before the era ended 5.3 million years ago.
As northern temperatures cooled during the Pliocene, grass lands that had developed in the Miocene spread. The first of the mammoths migrated into Europe about 3 million years ago. It became the Mammuthus meridionalis found in the cave paintings of Spain and France north of the Pyrenees.
The European Mammoth was already in North America when the late Pleistocene developed 1.8 million years ago. The species evolved into the steppe mammoth of central Europe (Trogontherii) and the Columbian mammoth (Columbi) that ranged from the northern United States into central America. Woolly mammoths (Primigenius) came later, when the cold became more intense in the north.
Based on the habits of modern elephants and the sizes of mammoth skeletons, zoologists believe Columbian mammoths would have needed about 500 pounds of food a day and up to 40 gallons of water. They also would have dropped about 400 pounds of dung.
If the grass were anything like modern timothy, there could have been as much as 4,000 pounds of hay on an acre. That could have supported eight mammoths for one day, or a larger herd for part of a day. Every day, as they mowed grass tops they left fertilizer and conditioned seeds.
Mammoths didn’t begin as grass eaters. In the early years of the Pleistocene, 1.5 to 2.5 million years ago, the European mammoth browsed woodlands of oak, ash, beech, hemlock and wing nut hickory. Their molars had comparatively low crowns with 12 to 14 ridges to chew leaves, bark and fruit.
During glacial advances, which trapped water, the climate dried. Winds blew sand against mountains, and loosened more grains that spread into great dune fields near the mountains. When conditions warmed, water collected. The Danube waterway that ultimately flowed across the northwestern lowlands toward England began developing around 900,000 years ago.
Local mammoths adapted to the steppe tundra marked by the light pink band bordering the gray glaciers on the map Their molars had higher crowns with 18 to 20 ridges to withstand the grit embedded in the coarse grasses. It’s droppings no doubt added to the growing fertility of the Ukraine and adjacent Danubian plains.
The Great Plains east of the Rockies was temperate steppe grassland (peacock blue on the map). Columbian mammoths had a few more ridges, perhaps 20 to 22. A male mammoth found in southeastern Utah’s Manti La-Sal National Forest had remains of sedge, grass, fir twigs and needles, oak, and maple in his stomach. The dung left in Bechan Cave, also in southeastern Utah, was 95% grass and sedge, with sedge composing about a third of the fossils. The rest were birch, rose, saltbush, blue spruce, wolf berry, and red osier dogwood.
It was colder in the polar and alpine desert where woolly mammoths adapted with heavier coats and 26 ridges on their molars. Last year, Eske Willerslev’s team published an analysis of 50,000 years of vegetation preserved in permafrost. It showed the environment was dominated by flowering plants like northern plantain, which thrive when their seeds are trampled. It was only when grass and shrubs replaced the forbs around 12,000 years ago that woolly mammoths disappeared.
The last known Columbian mammoth died 12,850 years ago. The American mastadon, Mammut americanum, survived a little longer in the plum colored taiga in the eastern part of North America until 10,500 years ago.
Notes: Pliocene temperatures were cooler than Miocene, but warmer than today. Some palaeontologists believe Trogontherii is the species that crossed into North America to evolve into the Columbian. The nomenclature and relationships between species have been refined several times. Most scientists would agree they could change again when more bones are found and more scientific tests are run.
Haynes, Gary. Mammoths, Mastodonts, and Elephants, 1993.
Lister, Adrian and Paul Bahn. Mammoths, 2007 revised edition; includes data on molar evolution.
Muitoni, Giovanni, Dennis V. Kent, Giancarlo Scardia, and Edoardo Monesi. "Migration of Hominins with Megaherbivores into Europe via the Danube-Po Gateway in the Late Matuyama Climate Revolution," Rivista Italiana di Paleontologia e Stratigrafia 120:351-365:2014.
Peters, Amy. "How Many Bales of Grass Hay per Acre from the Average Pasture?," Oregon State University Extension Service website. Any estimate of pounds per acre makes assumptions about species, moisture, and soil fertility. This is a generic number. If you lower the yield, you simply decrease the size of the herd.
University of California, Berkley. "About Mammoths," university website.
Willerslev, Eske, et alia. "Fifty Thousand Years of Arctic Vegetation and Megafaunal Diet," Nature, 6 February 2014. The northern plantain is Plantago canescens.
Graphics: "Last Glacial Maximum Vegetation Reconstructed vegetation cover at the Last Glacial Maximum period ~18,000 years ago-( ~16th millennium BC), describing the type of vegetation cover present, based on fossil pollen samples recovered from lake and bog Sediments." Based on J. M. Adams, Global Land Environments since the Last Interglacial, 1997, and on N. Ray and J. M. Adams. "A GIS-based Vegetation Map of the World at the Last Glacial Maximum (25,000-15,000 BP)," Internet Archaeology 11, 2001. Uploaded to Wikimedia Commons, 16 December 2006 by Fabartus, revised 26 November 2007 by J. Rockley.
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