7 Mammoths walked the earth when the great pyramid of Giza was being built in Egypt.

The Island of Wrangel was isolated from the mainland for about 6,000 years. The island provided refuge to woolly mammoths until 2500-2000 BCE. The size of the herd ranged from 500-1000 mammoths.

While the woolly mammoths were surviving on the island situated in the Arctic Ocean, the Pyramid of Giza, one of the oldest pyramids of Egypt, was completed around 2560 BCE.

(source)

8 The Blue-ringed octopus is one of the world’s most venomous marine animals: their poison has no antivenom and can kill adult humans within minutes.

In spite of their small size and docility, the blue-ringed octopus is considered as one of the world’s most venomous animals. Their venom can kill 26 adult humans within a minute. No anti-venom has been discovered to counteract the toxin. This makes the blue-ringed octopus one of the deadliest reef inhabitants of the ocean. (source)

9 Oysters clean the water: An adult oyster can clean 30 to 50 gallons of water a day.

Oysters are filter feeders. They draw in the water over their gills. The gills trap the plankton and particles from re-entering the water. The Chesapeake’s Oyster population could clean the entire water volume of the estuary within three or four days. A process that would take about a year without the Oysters. Adult oysters can filter and clean up to 50 gallons of water per day. (source)

10 The Toucan’s oversized, colorful bill acts as a heat regulator. Toucan uses the beak to regulate the body temperature by adjusting the flow of blood to their beak.

The Toucans are known for their large colorful bills. Toucan’s bills are soft and do not make an effective weapon against predators.

The large bill acts as a heat regulator for the small bird. Arteries present in their bill expand when the bird gets hot. The expanded arteries release the heat, cooling the body. (source)

11 The male hooded seal has a membrane that looks like a large balloon when inflated. The inflated membrane is used to intimidate rivals during mating season.

The hooded Seal is like an Arctic seal. The male of the species has a black membrane in his nose. The seal blows air into the hood and makes it as big as a soccer ball to warn off other males during mating season. In addition, the hooded seal can inflate a red balloon-like sac through one of its nostrils. (source)

12 The Ligers are a hybrid cross between a lion and a tigress. They are the largest cat in the world and are known to grow at a rate of 1 kg every second day.

The Liger is a hybrid cross between a lion and a tigress (female tiger). Though hybrid vigor is often seen in the case of crossbreeds, it’s not the case with Liger. One of the differentiating factors between other crossbreeds and liger is a gene inhibiting growth.

With no inhibitor, a liger can reach a length of 3-3.6m. Ligers grow at the rate of 1 kg every second day. The liger is said to be the largest cat in the world and can weigh as much as 450 kg or 1100 pounds. (source)