Arctodus

Arctodus (Latin: "gigi beruang") — disebut juga sebagai beruang bermuka pendek atau beruang bulldog'— adalah genus beruang punah dari Amerika Utara di masa Plestosen, mereka muncul sekitar 3.0 juta tahun lalu dan punah 11,000 tahun lalu.

Mereka dikatakan sebagai karnivora, walaupun seperti beruang modern, mereka tidak selalu memakan daging. Tulang - tulangnya panjang dan ramping, dan dipercaya mampu berlari dalam jarak dekat lebih cepat dari beruang masa kini . Mereka adalah makhluk besar, dan bisa jadi predator puncak di masanya dan di daerahnya. Ukuran besar mereka, ditambah dengan kekuatan alami beruang, berarti mereka mungkin memburu megafauna Amerika Utara. Namun, karena hidup mereka bergantung pada megafauna Amerika Utara sebagai sumber makanan utama, mereka menghilang bersamaan dengan hilangnya mangsa mereka, sekaligus bersaing makanan dengan manusia.

Name: Arctodus (Giant Bear)

Pronounced: ARC-to-dus

Description:
Based on the skeletons that have been found, Arctodus stood 11.5 feet tall and weighed as much as 2,500 pounds--twice as big as the largest bears living today. Besides its enormous size, Arctodus had several features that set it apart from modern bears, including oversized teeth and a short muzzle relative to its wide skull, a fact that earned it the nickname "short-faced bear" or "bulldog bear." It also had unusually long front legs, which might have allowed it to reach speeds of more than 45 miles per hour and travel much greater distances than modern-day bears.

Fighting Style:
One of the giant bear's lethal weapons as a predator was its massive paws, equipped with long sharp claws and powered by a strong upper body. Its teeth also had the strength to crush bone, with a force that could reach more than 2,000 pounds per square inch. Arctodus was well-adapted for close combat situations, as it could intimidate with its sheer size and use its power to throw down and crush its enemies.

Home Turf: Across North America

When It Lived: Late Pleistocene Era (10,000 years ago)

What's For Dinner?:
Most scientists believe Arctodus was an apex predator in its habitat because it could run down and overpower its prey--mainly bison, but perhaps also larger animals such as wooly mammoths. Others have argued that despite having the size necessary to be a mega-predator, Arctodus was too light-boned to be able to bring down such huge prey. Some of them think instead that the giant bear was a scavenger, relying mainly on the kills of other predators for survival.

Did You Know?:
The giant bear, Arctodus simus, can be distinguished from another type of North American short-faced bear, Arctodus pristinus, by its superior size. The closest living relative to the short-faced bear that exists today is Tremarctos ornatus, more commonly known as the spectacled bear, of South America.

Megalodon

Megalodon adalah spesies ikan hiu purba raksasa yang hidup sekitar 20 hingga 1,2 juta tahun lalu. Hiu ini berukuran lebih besar dari sebuah kapal pesiar. Namanya sendiri berarti "gigi yang besar". Hewan ini termasuk jenis hiu perairan dalam yang jarang naik ke permukaan kecuali untuk mencari mangsa.

Isu yang tersebar, meski hiu ini belum pernah ditemukan dalam keadaan hidup, banyak di antara kalangan ilmuwan berpendapat bahwa hiu ini masih hidup, dan termasuk fosil hidup. Keturunan dekat hiu ini adalah hiu putih.

Twice the size of a great white shark, and with teeth 21cm long, this was the top predator of its time.

Type: Cartilaginous fish
Size: Up to 16m in length
Diet: Carnivore
Predators: No known predators
Lived: The Miocene and Pliocene epochs, 16-1.6 million years ago.

Name: Megalodon

Pronounced: MEG-a-la-don

Description: Measuring up to 50 feet long and tipping the scales at up to 50 tons, the Megalodon, a shark, was probably two to three times larger than today's great white shark. Its name means "long tooth," and its teeth were not only long but huge all around, with serrated edges.

Fighting Style: The Megalodon had an extremely sharp sense of smell and good eyesight; it was also very agile, which made it a lethal predator. After stalking and catching up to its victim, the Megalodon would use its rows of massive teeth to rip into its flesh. The shark would then retreat and allow its prey to lose blood, returning to attack again when the victim had become weaker.

Home Turf: Ocean waters around the world

When It Lived: Miocene and Pliocene Eras (roughly 25-5 million years ago)

What's For Dinner?: The Megalodon was an apex predator, at the top of the food chain in its waters. Its prey probably ranged from victims as small as seals (100 pounds each) to much bigger animals, including giant squid, other large sharks and, especially, whales.

Did You Know?: Sharks don't have bones, which makes it hard for paleontologists to estimate the Megalodon's size and shape. They did have some bony cartilage that fossilized, but most existing information about them comes from their teeth, which were replaceable. In guessing the size of the Megalodon, scientists estimate 10 feet for every inch of tooth.