Hippos are endothermic, but since most hippos mainly live
in Africa, they need to be submerged in water for most of the day because their
skin is vulnerable to overheating and dehydration. They have adapted to this by
spending most of the day with their body underwater and only part of their head
and nostrils above water in order to breathe.
Hippos don’t have sweat or sebaceous glands but they do
produce a liquid that turns red a few minutes after being in the sun. This
protects the hippopotamus’ skin from sunlight.
Their eyes, ears, and nostrils are positioned on their top
of their head so they can be submerged as much as possible and still be able to
hear above water noises, and breathe.
Most of the rivers that hippos live in are murky and filled
with bacteria and microbes. To protect themselves from disease and infections,
they same liquid their skin produces for sunlight protection is used. The fluid
becomes brown and works as an antiseptic. This antiseptic is extremely acidic
and is “hundreds of times more powerful than vinegar” (Hippo Sweat par. 4)
Hearing and Communication-
Hippos can produce and hear sounds above water and below
water. They also have adapted to be able to hear and produce both above water
and below water sounds at the same time, called simultaneous amphibious sounds
or SASs. These noises are made at the amphibious position, with ears, eyes and
nostrils above water, but the mouth and throat positioned below the surface.
Their exceedingly large lower jaw is especially adapted to make these calls and
conduct sound waves. The calls are made in times of danger and a hippo on the
surface will make an SAS sound, which causes hippos underwater to surface
1128). To warn other hippos of upcoming danger, these calls can be passed up
and down rivers to different herds.