The subject of hippo milk – and the question of whether hippo’s milk is pink – is one that’s been of increasing interest online in recent years, so we wanted to examine the topic in some detail.
Female hippos give birth to just one calf at a time and, as with all mammals, produce milk to feed their calves for the first stage of their lives… But is hippo milk actually pink?
The short answer is no. Hippo milk is definitely not pink. Like all mammals, hippos produce milk for their offspring that is a white/off white colour.
The longer answer is that the ‘pink hippo milk’ rumour has been doing the rounds online for some years now, and was taken into the mainstream by a National Geographic Facebook post on 26 July 2013, stating that ‘a hippo’s milk is bright pink’:
Despite any evidence to support this pink milk statement the rumor continues to spread, even as countless experts have dismissed the idea, such as biologist David Wynick.
Read on below for a fuller explanation as to why some people think hippo milk is pink. As with all rumours (or, dare we say, conspiracy theories), there is a kernel of truth!
Why do some people think hippo’s milk is pink?
The idea that hippo’s milk is pink likely comes from the fact that hippos secret an oily liquid from their skin, that for a time can appear pinkish. The secretion is referred to as ‘blood sweat’ – though it’s neither blood, nor sweat – and is secreted from mucus glands rather than sweat glands.
This ‘blood sweat’ is actually made up of two different acids – hipposudoric acid and norhipposudoric acid – that play an important role in the hippo comfort and health. The acids perform two functions:
- They act as a natural sunscreen, absorbing the UV rays that would otherwise destroy the hippo’s sensitive skin cells.
- They offer antibiotic protection, minimizing the growth of harmful skin bacteria whilst hippos are in the water. This allows hippos to live in some fairly toxic water with minimal risk of infection.
When the secretion comes out onto the hippo’s body it is colourless, but reacts to sunlight by turning to a bright orange-red colour, hence the term ‘blood sweat’. After a few hours, the liquid changes colour again to dirty-brown.
During the time after secreting ‘blood sweat’, whilst it’s still an orangy-red colour, it’s possible that this liquid could mix with a mother hippo’s off-white milk to turn it a pinky colour. But as we’ve discussed, it’s not the milk itself that is pink – rather the milk mixing with another liquid to change the colour.
That said, whilst it’s possible that hippos milk may appear pink, it’s unlikely, given that baby hippos are very efficient eaters, and form a very tight grip on the mother’s nipple between their tongue and the roof of the mouth. So tight in fact baby hippos can suckle whilst underwater.
Hippo milk & nursing facts
- Before and after giving birth, the hippo mother isolates herself from the herd for a few weeks to spend time alone with the baby.
- Hippos give birth underwater after an eight month gestation period.
- The first thing a new-born hippos does is to swim to the surface for its first breath.
- Baby hippos are able to suckle whilst underwater by taking take a deep breath, closing their ears and nostrils, and tightly wrapping their tongue around one of their mothers’ two teats.
- Baby hippos start eating grass at three weeks old, but are not weaned off their mother’s milk until around eight months.
- A single cup of hippo milk contains around 500 calories.
Final ‘pink milk’ thoughts
Despite promoting the pink hippos milk theory, it’s worth noting that neither National Geographic’s page on the hippopotamus nor their fact sheet on National Geographic Kids makes any mention of hippos having pink milk. Perhaps their highly liked Facebook post was a prank, or written by a confused employee.
And one bonus pink milk debunking point for you . There are also some people who believe that yak’s milk is pink. The truth of this pink milk myth as that the first milk excreted by a mother yak after giving birth contains blood that colors the milk pink, known as ’beastings’. After a short while, the blood disappears and the yak’s milk turns into a more normal off-white colour.
What are your thoughts on the great pink hippo milk debate? Any new evidence to add, or have a strong opinion either way? Let us know in the comments section below!
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