1 : Great Whales
The majority of great whales are of the baleen variety, meaning they don't have teeth but use a grill-like mechanism (the baleen) to filter food. The only great whale to have teeth is the sperm whale. The 200-ton blue whale is the largest baleen whale, followed by the 80-ton right whale, 75-ton fin whale, 60-ton bowhead whale and 45-ton sperm whale. In fact, the nine heaviest animals in the world are members of the great whale family. Not only is the blue whale the largest animal on the planet, it’s also believed to be the largest creature to have ever lived on Earth, bigger even than the T-rex and diplodocus. Even blue whale babies are huge, weighing 3 tons at birth and gaining 200 pounds every day for the first year of their lives.
2 : Elephants
Elephants, specifically African bush elephants, are the second largest animals in the world and the largest on land. The biggest elephant ever recorded weighed 10 tons and stood 4 meters at the shoulder. That’s pretty big, but only 5 percent of the weight of a blue whale and still dwarfed by the Bryde's whale -- the ninth largest baleen variety. African elephant babies are big too and it takes 23 months for mom to carry one from conception to birth.
3 : Hippopotamus
The hippopotamus (Hippopotamus amphibius), or hippo, from the ancient Greek for "river horse" (ἱπποπόταμος), is a large, mostly herbivorous mammal in sub-Saharan Africa, and one of only two extant species in the family Hippopotamidae (the other is the pygmy hippopotamus). After the elephant and rhinoceros, the hippopotamus is the third-largest type of land mammal and the heaviest extant artiodactyl. Despite their physical resemblance to pigs and other terrestrial even-toed ungulates, their closest living relatives are cetaceans (whales, porpoises, etc.) from which they diverged about 55 million years ago. The common ancestor of whales and hippos split from other even-toed ungulates around 60 million years ago. The earliest known hippopotamus fossils, belonging to the genus Kenyapotamus in Africa, date to around 16 million years ago.
4 : Rhinoceros
Five rhinoceros species exist: two in Africa and three in Asia. The African white rhino is the largest, weighing up to 2.5 tons when fully grown. Despite the name, the white rhino is a dark gray color. It is believed that the term “white” is a corruption of the original Boer description of this enormous beast, which they called the “wijde,” Dutch for “wide"—a description of the creature's mouth.
5 : Polar Bear
The polar bear is the largest carnivore in the world. Unlike with the elephant, rhino and hippo, much of its bulk is in the form of fat, which it needs to withstand the intense cold of its natural habitat. Despite their size and weight—adults weigh up to 1,500 pounds—polar bears are excellent swimmers and have been observed as far as 60 miles from the shore.
