Male kangaroos can get big, and depending on the species, they can be as tall as seven feet and weigh as much as 200 pounds. Much of those 200 pounds is pure muscle. If you check out the video ...

An adult male red kangaroo can stand over 1 1/2 meters tall ... It's lined with powerful, but flexible, muscles and ligaments. To keep the joey safe, mom can tighten those muscles to shut the ...