Link #32: Hippos Give Pink Milk!
As we grow older, we start making these automatic connections in our heads. The most common automatic connection we make has to do with colours. We think that certain things have to be one colour and no other. For instance, we believe that rivers are always blue but the dangerous River Rio Tinto in Spain, as we explained in an earlier post, is red!
Another assumption we make is that milk is always white or off-white. However, hippopotamuses debunk that assumption for us. Believe it or not, hippos actually give pink milk and it has nothing to do with blood!
Do Hippopotamuses Really Produce Pink Milk?
The colour of milk of all mammals on Earth is either off-white or white except for that produced by hippopotamuses. Hippos are known to give pink milk which is a result of their milk containing one of their unique secretions.
Hippos have this natural defence against bacteria on their skin and for protection from the ultraviolet rays of the sun. They secrete two types of acids on the surface of their body for this. The two acids are known as hipposudoric acid and norhipposudoric acid.
These acids make it impossible for bacteria to survive on a hippo’s skin. They also act as a form of natural sunscreen and prevent ultraviolet rays from harming the hippo.
While hipposudoric acid is red in colour like blood, norhipposudoric acid is orange in colour. In fact, the hipposudoric acid is often called blood sweat because of its colour. The reason hippos’ milk is pink is because it contains hipposudoric acid.
As you already know, if you combine the colours red and white, you’ll get pink. Whether the pink is prominent or just a light shade depends on the ratio of the colours you mix.
It’s unclear whether hippos give pink milk straight from their mammary glands or whether the milk mixes with the acids secreted by the glands located outside their teats.
Other Interesting Facts about Hippos’ Milk and Hippos in General
Hippos’ milk has other interesting qualities apart from its colour. For instance, a single cup of a hippo’s milk contains upwards of 500 calories. This makes hippos’ milk one of the most nutritious types of milk on the planet.
In fact, hippos’ reproductive process is all about making the calf as strong as possible as quickly as possible. Hippos give birth to their young while under water. This means that the first thing that a hippo baby has to do is swim upwards to get some air.
Hippos are also very protective of their young. They are known to be extremely aggressive in general but even more so when they are nursing. Furthermore, like many mammals, hippos have a tendency to live in groups. Effectively, a hippo baby is not only cared for by its mother but also other female hippos in the herd.
It is also important to note that a hippo’s milk can be ejected under water. When this happens, the baby hippo dives under water and closes its nostrils and ears to nurse. Since hippos can survive under water for around 30 minutes, this doesn’t pose much of a problem.
Hippopotamus are featured in the following book:
25 River Monsters
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