The prehistoric Earth was full of terrifying animals that reached sizes unlike anything alive today. Many modern species, both large and small, are dwarfed in comparison to their prehistoric relatives.

The species below look a lot like animals you'd recognize, but with one key difference: they're much, much bigger. From snakes that can eat a crocodile to a crocodile that can eat a dinosaur, these extinct animals are not the kind of animals you'd want to live in the same time period and place.

Gigantopithecus blacki

• Where: Asia
• When: 300,000-1 million years ago

Gigantopithecus blacki. Image: Wikimedia Commons

O Gigantopithecus blacki, the largest ape that ever lived, was 10 feet tall and weighed over 500 pounds. His enormous bulk and brute strength kept the Gigantopithecus safe from the predators it lived with - including tigers, leopards and black bears. Despite its large size, it was a herbivore, using its heavy, muscular jaws to chew on the tough grasses found in the forests.

Daeodon shoshonensis

• Where: North America
• When: 18-25 million years ago

Daeodon shoshonensis. Image: Wikimedia Commons

Daeodon shoshonensis was a type of extinct, carnivorous pig. Its meter-long skull housed formidable jaws filled with teeth perfectly adapted for shattering bones and cutting meat. A formidable hunter, it had on its menu the primitive horses and camels.

Dunkleosteus terrelli

• Where: Global
• When: 400 million years ago

Dunkleosteus terrelli. Image: Wikimedia Commons

A 10-meter-long giant fish with an armored head, the Dunkleosteus terrelli It could bite with a force of 5,000 Newtons. It could open its jaws (coated with self-sharpening teeth) in 1/15 of a second, creating a current to draw smaller victims into its open mouth.

Arctodus Simus

Arctodus Simus. Image: Getty Images

• Where: North America
• When: 12,500-800,000 years ago

The first humans had to compete with many fierce predators, and Arctodus Simus was among the biggest. Bigger than any bear alive today, it was four metres tall and weighed up to a tonne.

Titanoboa cerrejonensis

Titanoboa cerrejonensis Image/Reproduction: cobras.blog.br

• Where: South America
• When: 58-60 million years ago

Few animals can hunt crocodiles, but the giant snake Titanoboa cerrejonensis was one such beast. It grew to colossal proportions, often reaching 13 m in length and weighing over a ton.

Like modern anacondas, the Titanoboa used to lurk beneath the surface of a lake or river. Any prey that came close was quickly captured and dragged underwater.

Beelzebufo ampinga

Beelzebufo ampinga. image: Getty Images

• Where: Madagascar
• When: 70 million years ago

Beelzebufo ampinga was a terrifying amphibian for insects, lizards and even small dinosaurs. At 40 cm long and weighing 4 kg, it outnumbered even the largest frogs alive today, such as the kururra toad. As an ambush predator, it was probably hidden in the vegetation waiting for its prey.

Arthropleura

Arthropleura. image: Getty Images

• Where: Northern Hemisphere
• When: 280-340 million years ago

One of the largest crawling insects on planet Earth, the Arthropleura It resembled a 2 m millipede with 30 pairs of legs. It had a wide, flat, heavily armored body and fed on rotting leaves and any small animals it could catch.

Emperor Sarcosuchus

Emperor Sarcosuchus. Image: Alamy

• Where: Sub-Saharan Africa
• When: 110 million years ago

Only the jaws of Emperor Sarcosuchus were larger than an adult human. Once the crocodile captured a victim, the unfortunate prey would be unable to escape when the 10-ton crocodile dragged it back into the water, where it would be drowned and consumed.

The 12-meter-long crocodile was big enough to not only compete, but also attack the dominant animals of the time, such as dinosaurs.

Brontornis burmeisteri

Brontornis burmeisteri. image: Getty Images

• Where: South America
• When: 23-25 million years ago

The largest carnivorous bird of all time, the Brontornis burmeisteri, 10 feet tall and weighing 400 pounds, it was equipped with a huge beak and claws. As fast as a cheetah, this bird was also strong and preyed on the ancient relatives of the modern armadillo, which were heavily armored and grew to the size of a popular car.