Blue Whale (Balaenoptera musculus): The blue whale is the largest animal known to have ever existed, reaching lengths of up to 100 feet and weighing as much as 200 tons.
Giant Squid (Architeuthis dux): These deep-sea dwellers can grow up to 43 feet long. They are rarely seen alive, and much of what we know comes from specimens washed ashore.
Colossal Squid (Mesonychoteuthis hamiltoni): Even larger and more mysterious than the giant squid, the colossal squid can reach lengths of up to 46 feet.
Megalodon (Otodus megalodon): This prehistoric shark, which lived approximately 23 to 3.6 million years ago, could grow up to 60 feet long.
Argentinosaurus: This dinosaur, one of the largest known, lived around 100 million years ago. Estimates suggest it could reach lengths of up to 100 feet and weigh as much as 100 tons.
Whale Shark (Rhincodon typus): The largest living non-mammalian vertebrate, whale sharks can grow up to 60 feet long. Despite their size, they are filter feeders, and much about their migratory patterns.
African Elephant (Loxodonta africana): The African elephant is the largest land animal, with males reaching up to 13 feet tall at the shoulder and weighing up to 14,000 pounds.
Saltwater Crocodile (Crocodylus porosus): The largest living reptile, saltwater crocodiles can reach lengths of up to 23 feet and weigh over 2,200 pounds.