Patagotitan

Patagotitan mayorum holds a staggering distinction: it is the largest land animal we currently know of. First discovered in 2012 when a farm worker in Patagonia, Argentina stumbled upon a massive fossil protruding from the ground, the animal took years to excavate and describe.

The numbers are almost hard to process. At roughly 37 meters long and 69,000 kilograms — about the weight of 10 African elephants — Patagotitan pushed the upper limits of what biology allows for a land animal. At some point, legs simply cannot support more mass; Patagotitan was likely near that limit.

Like all titanosaur sauropods, Patagotitan had a long neck for reaching vegetation high in the tree canopy, a barrel-shaped body, and a long tail that served as a counterbalance. Its bones, while massive, were partially hollow — an adaptation that reduced weight without sacrificing structural strength.

A cast of the skeleton is so large that it doesn't fit inside the American Museum of Natural History — its neck and head poke out into the elevator lobby. The original fossils are housed at the Museo Paleontológico Egidio Feruglio in Trelew, Argentina.