Upper respiratory allergies and inflammation and swelling of the adenoids, the tissue at the back of the nose, can cause poor fluid drainage from the middle ear to the external ear and therefore cause a blockage in the Eustachian tube. Excess fluid can lead to middle ear congestion.
1 Black skin and Asian skin have thicker and more compact dermis than white skin. This is also why blacks and Asians have fewer facial wrinkles than whites. 2  Black skin has more casual lipids and more moisture in the stratum corneum than white skin.  Black skin has 50% lower ceramides than white or Hispanic skin.
This animal, which can weigh up to 5,000 pounds, has a longer, heavier head than its cousin and a noticeable hump on the back of its neck, absent in the black rhino. This hump consists of three layers: thickened skin, a pad of fat, and a thick muscle and ligament that support the animal's massive head. Researchers have noticed that when there's not enough food for the rhino, the hump shrinks the same way it does in camels, so they believe it is also an indicator of the animal's nutritional health.