1. Wolverine
The wolverine is just the size of a Cocker Spaniel or a Beagle (dog breeds), but has enough muscular strength to defend itself against other predators and bring down an animal as large as the caribou. Although it weighs somewhere around 20-50 lb, it has the ability of defending its food from a pack of wolves, cougars, and grizzly bears. Relative to its size, it is thought to be the strongest animal amongst mammals.
2. Honey Badger
Honey Badgers have powerful jaws and sharp teeth, which powerful enough to crush tortoise's shell.
They also have very tough skin. The skin is so thick and rubbery it's almost impervious to arrows and spears. Even a blow from machete can't scratch the skin. The Honey Badger is listed in the Guinness Book of World Records as the most fearless creature in the world.
The Honey Badger is one of the craziest animals ever!
3. Greater Grison
Like the honey badger, the greater grison is a temperamental carnivore. The greater grison is so fierce that it is unknown what, if any creatures outside of humans hunt them.
10. Tasmanian Devil
Its oversize head houses sharp teeth and strong, muscular jaws that can deliver, pound for pound, one of the most powerful bites of any mammal.
According to researchers, the Tasmanian devil's large head and neck allow it to generate one of the strongest bites per unit body mass of any land predator — 1,200 pounds (540 kg) per square inch — and their jaws are strong enough to gnaw through metal traps.
Despite its rotund appearance, the devil is capable of surprising feats of strength, climbing trees and swimming across rivers. Devils can't run at high speeds to chase down prey, but they are adept at distance sports: They can run about 15 mph (24 kph) for an hour straight.
.