An 11-foot-tall (3 meters), flightless bird that weighed almost as much as a polar bear inhabited Europe during the early Pleistocene, Live Science previously reported. Mammoths, saber-toothed cats, giant ground sloths and mastodons roamed North America during this period, according to the Florida Museum of Natural History (opens in new tab). The last ice age is known for hosting many large mammals called megafauna. (Image credit: Shutterstock) (opens in new tab) Life during the ice ageĪn illustration of a short-faced bear defending its territory from a saber-toothed cat during the last ice age. The sea level was much lower, and the shorelines were typically much farther out because glaciation trapped water in ice sheets, according to the American Museum of Natural History in New York City. Because most of the water on Earth's surface was ice, there was little precipitation rainfall was about half of current levels. Ice age conditions were also drier than today. At that time, global temperatures were about 11 degrees Fahrenheit (6 degrees Celsius) lower than they are today, according to a 2020 study published in the journal Nature (opens in new tab). The ice age peaked during the Last Glacial Maximum about 20,000 years ago, when glaciers covered vast swathes of North America, Europe, South America and Asia. Related: 'Last Ice Area' in the Arctic may not survive climate change How cold was the Pleistocene? For example, glaciers in the Antarctic Peninsula may date back to the earlier Pleistocene, according to the U.S. Ice age glaciers mostly retreated and melted away as the planet warmed after the Pleistocene ended, but some ice cover has stood the test of time. Scientists have identified four stages, or ages, within the Pleistocene epoch : the Gelasian (2.6 million to 1.8 million years ago) and Calabrian (1.8 million to 781,000 years ago), representing the lower or early Pleistocene the Chibanian (781,000 to 126,000 years ago), representing the middle Pleistocene and the late Pleistocene (126,000 to 11,700 years ago), representing the upper or late Pleistocene, according to the International Commission on Stratigraphy. The glaciers advanced during colder periods of the Pleistocene, called glacials, and retreated during warmer periods, called interglacials. The snowfall created glaciers and ice sheets, thus deflecting sunlight and continuing Earth's cooling trend, according to the National Oceanic and Atmospheric Administration's (opens in new tab) website. The Atlantic and Pacific oceans could no longer exchange tropical water, forcing warm water northward and increasing precipitation in the Northern Hemisphere, which fell as snow.
About 4.5 million years ago, the Isthmus of Panama land bridge formed between North America and South America, which may have triggered the last ice age. Earth has been experiencing a trend of cooling for about the past 50 million years.
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