Giant Animals & Mega Fauna "Megafauna are generally defined as those species animals whose average adult weight exceed 100 pounds (44 kg). The term is also used to refer to particular groups of large animals, both to extant species and, more often, those that have become extinct in geologically recent times. Megafauna animals are generally K-strategists, with great longevity, slow population growth rates, low death rates, and few or no natural predators capable of killing adults. These characteristics make megafauna highly vulnerable to human exploitation. Many species of megafauna have become extinct within the last million years, and, although some biologists dispute it, human hunting is often cited as the cause." From Wikipedia. Also visit Largest Organism on Wikipedia. BIG and ALIVE FAQ! Largest Animal: Blue Whale - 110ft in length and weighs 209 tonnes. Largest Land Animal: African Bush Elephant - 13ft high and weighs about 8 tonnes. Tallest Animal: Giraffe - up to 19ft tall. Largest Reptile: Saltwater Crocodile - up to 7 metres in length. Largest (Heaviest) Snake: Anaconda - 27ft in length, weighs up to 500 pounds. Largest (Longest) Snake: Reticulated Python - 26-32ft in length. Largest Moth: Atlas Moth - wingspan of 25-30cms. Largest Butterfly: Queen Alexander Birdwing - wingspan of about 23cms. Largest Beetle: Goliathus Regius - up to 11cms in length. Largest Bird: Ostrich - up to 9ft tall and weighing around 345 pounds. Largest Fish: Whale Shark - around 40ft long and weighs around 15 tonnes. Largest Invertebrate: Giant Squid - up to 43ft in length. Largest Carnivore: Southern Elephant Seal - up to 22ft in length. Largest Land Carnivore: Polar Bear & Brown Bear - up to 10ft long and 5ft tall at the shoulder. Largest Primate: Eastern Lowland Gorilla - up to 6ft tall and weighing 500 pounds. Largest Bird of Prey: Eurasian Black Vulture - 10ft wingspan. Largest Crab: Japanese Spider Crab - leg span of about 13ft BIG and EXTINCT FAQ! Largest Complete Dinosaur: Brachiosaurus (mounted in Berlin) - 38ft tall Largest Flightless Bird: Giant Moa - 12ft tall Largest Predatory Fish: Megalodon - 40-52ft in length Largest Elephant: Columbian Mammoth - 15ft tall and weighing 15 tonnes.