Meet the World's Grumpiest Frogs, the African Rain Frogs.

Don't get me wrong, these frogs aren't mad or sad. This is precisely how they look. Meet the African Rain frog, the little black guy who looks mad.

These frogs live on Africa's southern coast and can be found at altitudes of more than 3,300 feet. People have seen them dig tunnels that are up to 6 inches deep. Do you know why this is amazing? Because these frogs are so giant! They never get bigger than 2 inches. Isn't it amazing that such small animals can dig such huge tunnels?

As species that live on the edges of forests and dig holes, they don't need to be near water to survive. And when it feels threatened, this grumpy-looking frog can puff up and become more aggressive.

They often get more significant when they dig because that makes it harder for whatever is in their way to pull them out of their holes.

During mating season, the female releases a substance that sticks to the male and keeps him from falling off. The name for this is adhesive amplexus. And the female won't let go of her mate in any way. I don't know what else would be more loyal than that!

After the female lays the eggs, the male's job is to stay in the burrow and watch over the eggs until the babies hatch.

If you look closely enough, you can see that they are kind of cute.

Nature is something to behold.

More Info & Images Credit - db_born_wild / Facebook