In writing my merfolk centric fantasy novel, I've largely ignored any creatures of burden used within their society. Animals of burden were very important in the growth of human civilization, and the small supply of these type of animals (to my understanding) is one of the reasons why the Americas struggled to develop larger civilizations.

In the fantasy world of my story, I already had to confront the problem of not much usable food growing underwater - and so I simply invented a bunch of naturally growing underwater crops, that grow in abundance (though the merfolk still have a great number of issues with agriculture.)

Still though, I feel that there might be some reasons for the merfolk to use some fantasy creature, or at least domesticated version of a real sea creature, as a pack or plow animal. I am not certain how beneficial riding such creatures would be. Riding would require a lot of gear to stay on the mount (with a traditional merfolk tail) and if the mount could not swim faster than the merfolk, it's unlikely they would be in widespread use.

Cavalry I am sure what also lose much of its effectiveness. Unless you find some way to tame and ride a hostile sea creature like a shark, you probably aren't going to do anything resembling cavalry.

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    $\begingroup$ Ox and horse carts did not travel much faster than a man on foot if at all, but regardless they were plenty useful. $\endgroup$ Oct 11, 2022 at 8:49
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    $\begingroup$ Why do you need a hostile mount for cavalry? On land, war mounts are pretty much exclusively animals that are otherwise docile. You don't ride a horse into battle so it can bite someone. $\endgroup$ Oct 11, 2022 at 14:16
  • $\begingroup$ @NuclearHoagie it's because the advantage of a horse on land is in being a large hulking beast that in a formation can swarm over infantry, trampling them. You cannot do that underwater. $\endgroup$ Oct 11, 2022 at 15:57
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    $\begingroup$ @WasatchWind Why not? Having a horse run into you at full speed is going to hurt whether you get trampled underfoot or not. The physics of colliding masses is no different underwater. Underwater mounts can still break formations and cause damage without trampling. $\endgroup$ Oct 11, 2022 at 16:23
  • $\begingroup$ Perhaps. Reading some other responses here seems I underestimated the speed some sea creatures can travel at. I think one of my aversions to having merfolk cavalry is that I really, really don't want my merfolk civilization to feel goofy and gimmicky. I don't want them to be riding a seahorse just because it's punny. I want them to do what they do because it makes actual sense. $\endgroup$ Oct 11, 2022 at 16:41

5 Answers 5


Yes, they would.

I can affirm this because mounts follow the general yet extremely potent principle of specialization : A specialized entity -person, machine or animal- will always perform better than a generalist or worse, an incompetent one at the task it is specialized in.

The very concept of giving and sharing tasks with others -and by extension domestication- relies on the idea that you cannot do every tasks as well as at least another one : Biology constraints, experience and knowledge, all of these make you specialized for something, and weaker in others... Than others. After all, you cannot be good at everything! Combining merfolk aptitude at planning and resource management with carefully chosen pet skillsets will create synergies and give generally better outcomes.

To focus on mounts, here are a few hard advantages that mounts often have over their riders. Hard because, there's very little which can match those without excruciating costs behind or some modern machines. So now grab your whale, dolphin, seahorse (ok, perhaps not them) and go for this ride :) :

Maximum power output and sheer mass

Even in water, heavy house stones and tightly packed kelp balls will still be very heavy to move around. Like on land, take a big animal for these kind of tasks.

Also, have you seen an armoured horse charging at you? Worse, a war elephant? A metal-plated cachalot could break through any enemy lines with ease. Heavy mounts are great for frontline wars.


A mount can be faster than you. Unless your merfolks are moving very fast, they'll ride a mount. If you have big black marlins, I wouldn't be surprised to see merfolks attached to them running races, too1.

Burden transfer

When we basically do anything from walking to pushing stuff, we use our own energy. You can move this energy cost to a third party for two main benefits :

  • First, you can sit back and relax, enjoying a nice cup of Yorkshire tea while your mount does the job, Attach a carriage to a giant medusa, throw it in the Gulf stream and you're in for a gentle, peaceful ride along the flows.

  • They act as energy batteries. Use a pair of walruses to travel from Kelpington to Coral City, then exchange them for another pair to reach New Beach's town. You travelled twice if not thrice the distance you would have made alone, with very little efforts from your part.


Because not everything is physical, animals are also known to help people get through hard times or to live better with their mental disorders. Dolphins could be a good alternative to horses in that regard : smart enough and very social, sea?

Also, having a mount displays the social status of someone : If you manage to feed your 5 orcas, it means you have a good chunk of meat and money in your palms. Any people of high-status would have one mount just to show they're comfortable financially. In other words, rare or tough to tame mounts can make great positional goods.

1 : Well... I would be bubbling out loud of surprise by the whole scene, but not because of their speed :p.

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    $\begingroup$ Thank you kindly for the helpful comment. I'm especially interested in the mention of the fast swimming marlins. I've gotten into a misconceived idea I think, of the nature of the water somehow making it so that merfolk wouldn't find swimming for long periods of time tiring - or that transporting large quantities of material would somehow not take a great effort. One of these days I need to try scuba diving to get a better idea of the underwater environment. $\endgroup$ Oct 11, 2022 at 16:30
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    $\begingroup$ @WasatchWind If you happen to be next to the town's swimming pool, there might be human dolls which are used to learn high-level swimming and/or help people drowning, if you ask kindly to the monitor perhaps they could serve as a "kelp ball". Be warned, it's kinda tough! Or just swim a while and compare how much you can go before being tired compared to running. It could help see how much the archimedes effect help keeping things afloat vs how much the water's drag really hinders you when moving around. The latter really hurts ^^. $\endgroup$ Oct 12, 2022 at 13:07
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    $\begingroup$ Note that all our beasts of burden are herbivorous. It's because it is the relation of strength to the land area needed to feed them that matters. So I suggest the main beast of burden be manatees or something similar (baleen whales or whale sharks that feed on plankton may do), because you need them to eat less of or worse food than the number of merfolk of equivalent strength. Dolphins or porpoises would still be useful for hunting or protection in role similar to dogs, but for transportation they need too much fish. $\endgroup$
    – Jan Hudec
    Oct 13, 2022 at 12:42

Oxen, mules and company were not useful because they were fast, they were useful because they allowed to have more power available to perform tasks which would have otherwise taken the effort or several humans or be plainly impossible.

Therefore, if you can have a domesticated creature to help with for example transporting loads, that's already a win. You mentioned the difficulty of having the equivalent of agriculture: normally life rich waters are such because of the effective circulation between the surface and the bottom, mixing and transporting nutrients; a water beast of burden could be used to raise nutrients from the bottom through the water column, helping improving its productivity. This would be the water equivalent of tillage for land agriculture.


As a human-sized merfolk, especially with children, I think a pet porpoise, or even a pet killer whale, could be quite protective against sharks. Much like having a pet wolf, or pet bear or elephant.

The porpoise is about our same strength, but even without much in the way of natural weaponry, they are smart and fast and a nose butt can kill a shark; sharks fear them. And porpoises have "adopted" and protected humans at sea from sharks. Don't you want your mer-kids out playing with a porpoise or two?

Killer whales are fast, smart, far stronger than humans and as deadly as their name against sea predators. Thus good protectors. And if they can be domesticated to help carry burdens -- how much of a slaughtered whale can one of them carry home, versus one mer-folk?

Wolves were great hunters all on their own, better than humans in several respects (speed, scent tracking, hearing) but teamed up with humans because of our brains, our strategy, and our technology, we could kill at a safe distance, and take prey wolves could not. We provided them with a steady supply of food, and for animals that intermittently starved and gorged, a steady supply was enough. And they "get" working in packs (so do porpoises).

Find ways your merfolk with human intelligence makes life in the human pack easier and emotionally satisfying for the porpoises and killer whales, and they will provide both muscle and protection as their role in your society.

One thing I think humans could do that they cannot is provide some sort of medical care. Just like dogs and some other animals, saving an animal in dire need of medical care can create a loving friend for life. That includes feeding a starving animal, rescuing a trapped animal, warming a freezing animal.

I'm not sure what the analogs are for merfolk, or what you have them doing for a living, but get creative, translate the dynamics that led to us landfolk domesticating land animals, into merfolk domesticating sea animals.

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    $\begingroup$ Thank you for the very helpful answer. Did not know that porpoises were effective at fighting sharks, and I guess I didn't think about this kind of defense - not a mount, but still a helpful creature. I'll definitely consider this as I continue to build out my world. $\endgroup$ Oct 11, 2022 at 16:07

Chariots, chariots, chariots

Once upon a time, humans had a similar problem to the one you envision for your merfolk: they had a bunch of horses that were not that strong individually, and couldn't carry a rider very quickly or for long distances. So they tied a bunch of them to a cart and put a guy with weapons in the cart. The weight is distributed between individual animals, making it much less tiring.

Until horses were bred to bear an individual rider, chariots dominated plains warfare. Your merfolk could do the same, with the added bonus that they don't even have to invent the wheel for it! Just stick the "rider" into a harness, give them reins to control their pack of trained squids or whatever, and go for it. Give the merfolk long lances to avoid the problem of reaching the enemy.

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    $\begingroup$ Is that you Cave? $\endgroup$
    – Corey
    Oct 14, 2022 at 3:34

Humans already use underwater mounts so yes.

Humans spend less time underwater than merfolk and use mounts, why wouldn't merfolk?

Dolphins, sea lions, and seals are most commonly used as they're very intelligent and easily trained. They can carry great loads, detect enemies and food with sonar, and their bodies are much better suited to moving quickly.

Unless the merfolk are magically quick, their bodies probably aren't as well suited to the sea as actual underwater animals who are fully ready for it. Having underwater servants is a massive advantage to any prosperous nation.

For riding, just hang on the back.

You could likely design some sort of rope to hold on the back. You swim behind the dolphin, being dragged by it and adding in your speed to move.

  • $\begingroup$ Ouch, that sounds like an uncomfortable harness lol. The merfolk are suited to the sea. They have tails and such. I'm not going for realistic merfolk, but just a feeling of plausibility. Thank you for your response. $\endgroup$ Oct 11, 2022 at 16:00
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    $\begingroup$ @WasatchWind It would be much more uncomfortable, and un-hydrodynamic, to "ride" a sea creature in a manner similar to a horse. $\endgroup$ Oct 11, 2022 at 17:02
  • $\begingroup$ They have tails, but do they have aerodynamically shaped bodies completely filled with muscle? They may be faster than a human underwater, but dolphins and such are much much faster than humans, and much more able to swim freely. $\endgroup$
    – Nepene Nep
    Oct 11, 2022 at 17:56
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    $\begingroup$ I imagine "saddles" would have a very different shape underwater, especially if the mount's speed was important. You might have differences between saddles for draft animals / tasks and those for racing / warfare. The latter could extend the streamlined shape of the animal to cover the rider, or place the rider mostly in the lee behind the creature's maximum diameter. Compare the difference in windscreens for different models of motorcycle: revzilla.com/motorcycle-windshields-windscreens $\endgroup$ Oct 12, 2022 at 17:03
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    $\begingroup$ When you mentioned mounts I was more thinking of these: en.wikipedia.org/wiki/Diver_propulsion_vehicle $\endgroup$
    – Michael
    Oct 12, 2022 at 19:19

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