Have you ever wondered how animals protect themselves from the sun, especially under the blistering sun in the Africa?
Humans suffer with sunburn and sun damage when exposed to the suns harmful UV rays. We have to wear sun screen and clothes to protect ourselves. Our skin isn’t completely useless, as the more melanin we produce, the more natural protection we have. However, it’s not full proof. Many animals have natural defences like skin pigmentation (melanin), fur and scales that provide protection from the suns UV rays. Some animals look for shelter or find covering themselves in mud provides a protective barrier and helps to keep them cool.
What about animals that do not have fur?
Hippopotamuses do not suffer from sunburn, even with their fur-less skin and despite spending all day basking in and around highly-reflective water under the glaring African sun. Scientists have discovered that hippos secrete oil droplets from their skin that act as their natural sun protection. This oil appears as if the hippos are producing red sweat, which gives them a flushed appearance.
Here comes the science …
The oil is made up of two highly acidic compounds, one red, which they named hipposudoric acid, and one orange, which they named norhipposudoric acid. Although the two chemical pigments are unstable on their own, when they dry on the animal’s skin in the presence of mucus, they harden and stick around for hours. This thick, sticky mixture is tough enough to survive on the hippos’ skin no matter how long they stay emerged underwater. The UV spectra of the pigments also indicate that they absorb the harmful ultraviolet rays.. The hipposudoric acid is also a powerful antibiotic. The antibiotic properties produced by the hippos skin may explain why hippos wounds rarely become infected. Male hippos have frequent and aggressive fights and it isn’t surprising with those large, strong teeth that injuries occur. Their teeth have no purpose for foraging or eating, the large lower canines and incisors have evolved for their protection. They are notoriously known as Africa’s most dangerous animal.
Hippos have incredibly evolved to produce an antibiotic, protective sunscreen to survive in their natural habitat. Animal adaptations are incredible, and to think we need a team of scientists to create our sunscreen. It makes us look very inferior. Don’t you think?
Come back next Friday for more interesting facts, #factfriday !
Resources
- Hashimoto. K, Et al. 2007 Studies on the red sweat of the Hippopotamus amphibius – https://www.degruyter.com/downloadpdf/journals/pac/79/4/article-p507.pdf
- Saikawa.Y, Et al. 2004. The red sweat of the hippopotamus. https://www.nature.com/articles/429363a
