Mermaid Biology- Could They Be Pretty Platypuses?

Alright, yes – the title of this post does pose the weirdest question ever asked on this blog, so I’ll tell you all how I came round to this hypothesis…

It started as a comment on a blog post about films, asking how The Little Mermaid would reproduce… it was a pretty random question; but one that got me thinking…

Ariel, the Little Mermaid

Ariel, the Little Mermaid - So pretty... but how do you breed? (image from

You see, if a mermaid has a human top then it would be likely that she would produce milk for her young – technically making her a mammal. On the other hand (or half, you could say), mermaids have fishy tails. This suggests that instead of giving birth to live young, they may lay eggs.

A mammal that lays eggs and lives in water? Sounds like… a platypus!


The Platypus is one of only a few mammals to lay eggs (image from

The platypus is a monotreme.

“The only surviving examples of monotremes are all indigenous to Australia and New Guinea, although there is evidence that they were once more widespread. Among living mammals they include the platypus and four species of echidnas (or spiny anteaters).” – Wikipedia

So, essentially my theory is that a mermaid could also be a type of monotreme; laying eggs and then looking after the young when they hatch… The eggs would have to be laid on land, as platypus eggs are – they would simply drown if they were laid under water. Perhaps there are caves with mermaid nests in. That’s a pretty cool thought!

Of course, this is glossing over the whole ‘ do mermaids breathe underwater?’ issue… If they are able to breathe underwater they must have gills, which means that they would not be mammals at all; gills simply cannot provide enough oxygen from the water to sustain a mammal.

“Cold blooded animals need a lot less oxygen than warm blooded animals do. Imagine that you have a 100-pound human and a 100-pound fish sitting on a couch. A human being needs maybe 15 times more oxygen than the fish does. If the human then gets off the couch and starts swimming, the human needs even more oxygen. So does the fish, but fish are super-efficient in the water… Compared to air, there just is not enough oxygen dissolved in water to keep a warm-blooded animal going.How Stuff Works Express

In most myths of mermaids, they are often seen on rocks – so gills would seem unlikely as they cannot function properly out of the water. This, along with the fact that images of female mermaids pretty much always includes mammary glands (hee hee – boobs! Sorry, couldn’t resist!), seems to suggest that actually the species would be classed as a mammal and thus would have to surface to breathe like a seal or a dolphin.

So there you have it: my theory that mermaids are actually a type of monotreme mammal; living in the water but having to surface to breathe, laying eggs on land and then feeding the young on milk until they can swim and fend for themselves.

I think it’s a good theory. If only mermaids actually existed…



Filed under Randomness and Musings, Science and Geekery

4 responses to “Mermaid Biology- Could They Be Pretty Platypuses?

  1. Very good reasoning and certainly much better thought out than some of the suggestions I’ve seen that sailors were deluding themselves into thinking sea otters (cute as heck but not really sexy?) or dugong /manatees(gentle giants whose mother’s probably think they are lovely, but my goodness you’d have to be a bit mad to think they were cute or sexy) were actually mermaids. Although of course not everyone could afford spectacles to correct sight impairments in those days…

  2. Heh, thanks… I’ve always wondered where the theory that manatees are mermaids came from. The lack of specs might explain it…. 🙂

  3. chvinson10

    i say theres like…fields or something and they’re like little clams that are collected then like sent to nursureys or something then they…er…hatch per-say. yea thats it i think. wether they’re full grown or “mer-babys” i have no idea you’ll have to figure that out on your own.

    • I like that – nurseries of mer-babies… I can picture them all swimming about and frolicking. I think that’d be pretty sweet.

      Thanks for the comment.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s