Hippos are basically gentle animals. They would rather run away than fight. And because of their enormous size and sharp teeth, few animals try to attack them. Mostly hippos fight each other.
Male hippos fight over leadership of a herd. Or they fight over who has control of a water area or mudhole. When two hippos clash, it becomes a contest of weight and strength.
Most hippo fights take place in the water. The opponents move backward side by side in a circle. Then, using their massive heads as sledgehammers, they swing them toward each other and ram their open mouths together.
Few animals can open their mouths as wide as hippos can. One reason hippos stretch their mouths so wide is to scare away other animals.
Hippos often fight for up to two hours, with only short rests. The longest hippo fight on record lasted eight hours! When hippos fight, they use their razor-sharp teeth as weapons.
When fighting, hippos use their mouths like buckets to toss water at each other. They also grunt, growl, snort, bellow, honk, and roar as they charge at each other.
The common hippo has two tusk-like canine teeth in its lower jaw. Hippo canines can be up to 20 inches long, and can weigh more than 4 pounds each. Like elephant tusks, a hippo’s canines keep growing throughout the animal’s life.
Young or old, almost all hippos are scarred from fighting. A layer of fat under their thick hide protects their body organs and muscles.