The Pleistocene Era began 1.8 million years ago and ended roughly 10,000 years ago. During that period were several Ice Ages. Many giant sized animals and birds that seem familiar to us (because they resemble modern animals) roamed the earth. They became extinct, possibly due to environmental conditions or disease, or possibly because they were hunted by humans.
The Irish Elk (Megaloceros) is the largest deer species ever, although it was not an elk, nor was it exclusively Irish. Megaloceros ranged across Europe, Asia, and northern Africa. The biggest specimens are seven feet tall at the shoulder and have antlers that span 12 feet! It became known as the Irish Elk because the Irish would find remains in peat bogs and display the antlers in hunting lodges as if they bagged the beast themselves. Because of its wide geographic range, it is not known when the last of these deer died out.
Giant Short-Faced Bear
The Giant Short-Faced Bear (Arctodus simus) had the ability to run on his two long hind legs, and may have reached a running speed of 40 miles per hour! It would have been a frightening sight, as this bear stood five feet tall on four legs, but rose to 12 feet when standing up. It lived in the western US, Canada, and Alaska.
The fossil bones of giant Syrian Camel was only discovered two years ago in central Syria. The 12-feet-tall at the shoulder bones are around 100,000 years old. Previously, scientists thought camels had only existed in the Middle East for about 10,000 years.
The Giant Ground Sloth (Megatherium americanum) weighed five tons and stood 12 feet tall on its hind legs! Native to South America, it ate tree leaves like its descendants, the modern sloths, but was way too heavy to climb. There were several other species of large ground sloths that inhabited North America, none as large as Megatherium. Although giant sloths died out 10,000 years ago, the last species of ground sloths may have survived until 1550 AD in the Caribbean.
Saber Toothed Tiger
There were several species of Saber Toothed Tiger (Smilodon) in both North and South America during the Ice Age. The largest, Smilodon populator lived in Brazil and had canine teeth up to seven inches long. It probably weighed about 800 pounds, the size of a modern lion. Saber toothed cats are believed to have co-existed with humans for about a thousand years, and may have been hunted to extinction.
North American Lion
The North American Lion (Panthera leo atrox) was bigger than the Smilodon species, but hasn't gotten as much press because there are not as many fossil specimens, or maybe because they had proportionally normal sized teeth for a big cat. They were still big teeth, since the largest lions were over eight feet long! (Image: Dantheman9758)
The Giant Beaver (Castoroides ohioensis) wins the prize for the largest rodent, at least in North America. Skeletal remains have been found indicating the animal was about nine feet long. Although they didn't have the characteristic flat tail of the modern beaver, they resembled their modern cousins otherwise.
Giant Pleistocene species weren't limited to mammals. The Teratorn (Argentavis magnificens) was an ancestor of the Giant Condor with a wingspan of 19 to 28 feet! With wings folded, it stood as tall as a man and could weigh over 200 pounds. Found in Argentina, it was the largest flying bird ever known.
Mastodons (Mammut americanum) were not mammoths, although both were hairy, resemble elephants, and roamed North America until ten thousand years ago. Mastodons ate from trees, while mammoths grazed on the ground. Mastodons are somewhat shorter and stockier than mammoths, reaching about ten feet tall. They weren't any larger than elephants that exist today, but they were pretty big animals anyway.
The Wooly Mammoth (Mammuthus primigenius) belonged to the same family as modern elephants, and were about the same size. They lived in Europe, Asia, and North America ranging up to the Arctic. Woolly Mammoths in the northernmost areas had hair up to three feet long, and curly tusks up to five feet long. Mammoth survived longer than other Ice Age giants, with the biggest extinction occurring about 8,000 years ago. A dwarf species survived on Wrangel Island near Siberia until about 1700 BC. (Image: Mauricio Anton)
The dinosaurs got really big, and they died out. Pleistocene mammals grew very big, and they died out. It makes you wonder... where will the human obesity epidemic lead us?