The Extreme Mammals Image Gallery

Honorable Mention

Megatherium: Finally, he may have been bumped from the list by a horned rat, but I'll always have love for the giant Peruvian sloths of yesteryear. The 20-foot-tall (6 m) Megatherium was as big as a modern elephant and used its hooked sloth claws to bend leafy tree limbs to its lips. What a noble-looking creature...

About the Author: Robert Lamb spent his childhood reading books and staring into the woods — first in Newfoundland, Canada and then in rural Tennessee. There was also a long stretch in which he was terrified of alien abduction. He earned a degree in creative writing. He taught high school and then attended journalism school. He wrote for the smallest of small-town newspapers before finally becoming a full-time science writer and podcaster. He’s currently a senior writer at HowStuffWorks and has co-hosted the science podcast Stuff to Blow Your Mind since its inception in 2010. In his spare time, he enjoys traveling with his wife Bonnie, discussing dinosaurs with his son Bastian and crafting the occasional work of fiction.