Do you know why kangaroos always hop' It’s because kangaroos are mostly arid-dwellers and often have to travel long distances in search of food and water. Now, all of us know it takes a lot of energy to travel in arid regions. And hopping saves more energy than running or galloping. In fact, a hopping kangaroo also uses less energy to breathe than one standing still. That’s because the air is pushed out of the lungs by the impact of the organs against the diaphragm, each time it hits the ground.