00:07With our planet around for nearly five billion years, countless species have walked or crawled
00:13on its surface. Some of them have managed to fight for their existence and staved off extinction.
00:19Here are 11 prehistoric animals we're glad are extinct.
00:26Extinct nightmares. Although many organisms are alive today, some animals haven't been so lucky.
00:32When it comes to some animals, we should sigh with relief that they aren't around
00:36and can only live in our nightmares. Here are some extinct animals that are probably better left
00:42in the past. Titanoboa. Many are already wary of snakes, but what about their prehistoric ancestors?
00:5260 million years ago, a snake called Titanoboa crawled around the planet.
00:57Living in tropical rainforests, this enormous snake is thought to be 50 feet long and had over 250 vertebrae.
01:07Dinosuchus. Dinosuchus is an extinct species of crocodile,
01:11but something made it stand out from its modern-day cousins. Dinosuchus was big, a lot bigger than the
01:17crocodiles we know at an estimated 35 feet long. Evidence points to it getting into fights with
01:22T-Rex to make it even more imposing. Arctotus. The Arctotus was a bear that roamed North America
01:32until possibly only about 12,000 years ago. The giant bear could stand at an enormous 11 feet high
01:39on its hind legs and run at 40 miles an hour. They weighed an estimated 1500 pounds.
01:49Megalodon. This list wouldn't be complete without the iconic Megalodon. The Megalodon
01:54was similar to a great white shark but was much bigger. They went extinct 3.6 million years ago and
02:01paleontologists have managed to determine their massive size due to finding fossilized teeth.
02:05The shark could be as long as 33 feet. Gigantopithecus. When people in Asia first started finding
02:15Gigantopithecus teeth, they thought giants used to roam the earth. Gigantopithecus was similar to a
02:22modern-day orangutan standing nearly 10 feet tall and weighing over 600 pounds.
02:31Phorus racidae. Phorus racidae, also called the terror bird, was a large flightless bird that was also
02:37a predator. With fossil evidence, terror birds could be as small as 3 feet and others as tall as 9
02:43feet.
02:44They chased down their prey and were apex predators in South America.
02:51Arthropleura. Even the smallest bugs make people's skin crawl today, but what about a giant
02:56millipede? Arthropleura was a giant arthropod that could be as long as 9 feet. They were so large
03:02because Earth's air was more oxygen-rich than today's. They died out about 290 million years ago.
03:12Smilodon Fatalis. The Smilodon is a notorious extinct animal seen in all media today.
03:18Colloquially called the saber-toothed tiger, the Smilodon was the largest example of a saber-toothed
03:24cat and would be the length of a lion but much bulkier. The animal was bold enough to go after
03:29even the biggest prey mammoths. Megalania. Megalania was an enormous lizard and cousin
03:38to our modern Komodo dragon. Like Komodo dragons, Megalania evolved to rip and tear flesh, hunt and
03:44scavenge for food. They could be 18 feet long and weighed up to 1,300 pounds.
03:53Megapirana. The Megapirana was a cousin to the piranhas we have today, but on a much larger scale.
04:00The extinct carotene fish that lived around Argentina weighed 22 pounds and was 27 inches long.
04:07It is thought to have gone extinct because the population became isolated in shallow basins,
04:12where its numbers slowly diminished before going extinct.
04:18The Rhizinosaurus. The Rhizinosaurus was a dinosaur that lived around 70 million years ago.
04:24What sets them apart from other velociraptors is the large knife-like claws they have on each hand.
04:30Thankfully, they would have used them more for pulling vegetation than hunting prey.
04:34Yankee Ammonish.
04:34The Rhizinosaurus. The Rhizinosaurus did not work for the
