I'm designing a world where people and dinosaurs exist at the same time. I'm making it realistic (in the sense that it is more like Jurassic Park and not like The Flintstones).

Supposing you could tame an adult male triceratops, is there a way to estimate how much load it could pull/carry? I'm envisioning a cart with wheels, but if the tail is too much of a blocker for that then stowing stuff on its back and sides would do nicely too.

• Look to real world animals... the elephant's not a terrible analog. They're roughly half the weight of the largest triceratops. Google's suggesting that elephants can pull 18,000 pounds or more, and in the context of dragging logs on the ground (no wheels). There's probably no reasonable load you could apply to this scenario that's implausible. Many thousands of pounds carried (even a mule can do 200), tens of thousands pulled. Mar 25, 2020 at 14:58
• Are you going to have brakes? Because I always felt bad for Fred's heels. Mar 25, 2020 at 15:51
• @BLT-Bub consider plain terrain. Mar 25, 2020 at 16:03
• The cart should not be a problem the cart does not need to be further away than a the front horses on a 4 horse cart team. you can also make the cart taller to give more room.
– John
Jun 18, 2020 at 15:36
• @chaslyfromUK That wouldn't work. The main leg retractor muscles on a Triceratops (the caudofemoralis) attach to the tail. Remove the tail and the animal wouldn't be able to walk or would at best be severely crippled. It's been suggested that's why so many bites from tyrannosaurs seem to be on the tail. Jun 25, 2020 at 17:22

So a triceratops would mass about 6-12 tonnes, according to wikipedia.

Draft horses that weigh 1 tonne can pull carts of 2 tonnes. Elephants working in logging drag 2t logs (about half their weight) in the course of their work.

So for a 6 tonne triceratops, that suggests a 12 tonne cart, or 3 tonnes of dragging. (Despite many cars being only about 2t, I don't think a triceratops could drag one if the parking brake was on. Too much friction.) For the 12 t, that's a 24 t cart, or a 6 tonne drag.

As far as actually carrying something by strapping it to the side or putting it on a harness, for horses it's recommended to not exceed 20% of body weight. A triceratops is a bit more stocky, but because of the square-cube law I don't actually think there would be improved specific capacity. So 1.2 to 2.4 tonnes carried.

As far as pulling the cart goes, one option is to have two smaller carts on either side, just behind the legs, and use that. Another option is just to have a really long shaft between the harness and the rest of the cart. (It'd probably need to be 3-4 meters long)

• A elephant can easily drag a parked car, a triceratops would not have a problem. Some part on the car will give out before the trike does.
– John
Apr 24, 2020 at 3:40
• This does not take into consideration the extreme robustness of a Triceratops' limbs in comparison to an elephant's. It's pulling capacity would be much greater. Jun 19, 2020 at 14:44

Triceratops is an example of a very large mediportal animal: an animal that is large, but adapted for relatively rapid locomotion. This can be seen by the structure of its limbs, which unlike an elephant or a more contemporary sauropod, are not columnar, but semi-flexed, a design that allows rapid acceleration. This would fit with its horns: when defending against a predator, it would need to be able to turn quickly and lunge quickly in order to stab at its foe with its horns. The robustness of the leg bones even in comparison to an elephant or sauropod suggests that this is likely. A side effect of being able to accelerate quickly is being able to also run quickly.

Now, we must consider that Triceratops is estimated to have a body mass of 6 to 12 metric tons.

If we consider modern horses, it can be seen from their skeletons and lifestyle that they are a large cursorial species, adapted to running. However, being cursorial does not necessarily equate to maximal load-bearing or -pulling capability: horses' legs are slender at the bottom and relatively far up the limb, and then bulk out near the body, which are classic adaptations to minimising the mass of the limb in order to maximise the rapidity of the gait cycle.

However, Triceratops has far more bulky, robust limbs that are proportionally shorter than a horse's. Despite its longer legs in absolute terms, it is unlikely that it would have been anywhere near as fast as a horse. As I have pointed out, Triceratops seems evolved for making rapid turns and lunges, probably so that it can use its horns as weapons.

So, if a 1 metric ton draft horse can pull a 2 metric ton cart, scaling up the creature to a 6 to 12 ton Triceratops would naively give a hauling capacity of 12 to 24 tons... but this does not take the creature's musculature into consideration.

If we compare a horse with a Triceratops, the comparison is similar to that between a marathon runner and a weight lifter. Even if they weighed the same, the weight lifter would run less quickly and for a lesser duration, but could pull a much greater weight.

A human Marathon runner might be able to lift his own body weight, or perhaps a bit more. However, his training has been more toward lightening his body and increasing his endurance. This is in contrast to a weightlifter, who might be able to lift 2.3 times his own body mass. The comparison between a horse and a Triceratops is that extreme, perhaps even more so.

So, with Triceratops being one of the weight lifters of the animal kingdom, we can expect that they could pull a much greater load than an equivalent-sized horse. If we go with a not unreasonable figure of 2.5 as the greater weight-pulling capacity of a Triceratops as compared to a horse, then we must conclude that a Triceratops's pulling capacity would be on the order of 5 times its body mass... so for a 6 to 12 metric ton Triceratops, it might be able to pull a 30 to 60 ton wagon, provided that the friction of the horse-sized and Triceratops-sized wagons was equivalent.

I mentioned elephants in passing. Elephants have relatively slender limbs for such a large animal, and they are also relatively slow, despite their relatively long legs. A rhinoceros of the same mass has shorter, stronger limbs, and is also faster, as it can gallop, bringing all of its feet off the ground for part of its gait cycle, while an elephant cannot gallop at all.

So, since a Triceratops is equivalent to a physiologically even stronger rhinoceros rather than an elephant, the pulling capabilities of an elephant are a poor example for comparison.

Now, having said that a Triceratops can likely pull vast masses, I would not expect that it could pull them particularly quickly, but it is likely that they could pull a load for a considerable amount of time. Lunging with its horns at a predator would require anaerobic fitness, rather than aerobic fitness. However, Triceratops has a deep, broad rib cage which would be able to house a large heart and a large set of lungs, so it is likely that it could keep up a fairly decent walking pace for a considerable amount of time.

Triceratops dentition consists of around 800 teeth arranged to slice up very fibrous food. This would mean that their preferred diet may have been something like fern fronds or even tree-fern trunks. They would need to spend a considerable amount of time eating in order to meet their energy needs.

The fact that Triceratops has a vast battery of teeth implies that its digestive system is more reminiscent of a horse than a cow, in that it must chew its food thoroughly before swallowing it, and that it does not have the opportunity to re-chew its food as cows do. Cows are forgut-fermenting herbivores, while horses are hindgut-fermenting herbivores.

The significance of this is that a Triceratops could likely eat rich, high-energy food (as can a horse), while a cow cannot, lest it suffer from a digestive imbalance that can be lethal. This would tend to make domestication of Triceratops for purposes of haulage feasible in that eating rich food gives it the ability to gain the nutrients it needs in less time than eating its usual poor-quality food, therefore increasing the time that it can spend working.

On the matter of carts, ball- or roller- bearing axles would reduce the friction of the wood-on-wood bearing surfaces of pre-modern carts, as would having carts with flanged steel wheels running on metal rails, as both these measures decrease rolling resistance. Rubber tyres would have the effect of providing a smoother ride, but at the cost of increasing rolling resistance.

However, as typically happened in pre-modern times when the only power was muscle power, if more power was needed, more animals were added. However, with a single Triceratops likely being able to pull a 30 to 60 metric ton cart, it would be difficult to build a cart that could carry that much, let alone twice that much.

In fact, the extreme strength of a Triceratops would suggest that the more likely arrangement of animal and load would be a train of carts pulled by a single animal, since the individual carts may need to be able to be moved by lesser beings on occasion, as well as the cost involved with producing a single 20 to 40 ton capable cart as compared to the cost of 10 to 20 two-ton capable carts.

Frame Shift Challenge: You might want a hadrosaur instead of a Triceratops

Ceratopsians don't appear to have been particularly fast dinosaurs or have a lot of endurance. They appear to have been slower than big predators like Tyrannosaurus, who wasn't very fast in the first place (speeds of 40 km/h). The semi-sprawling forelimbs of Triceratops are really bad for long-distance running or walking, but are really good at helping the animal turn. By using its hips as a pivot, Triceratops could rapidly swivel around and make sure its horns were pointed at a potential threat at all times. This also means it's really hard to put a saddle or harness on them, as a Triceratops can rapidly turn around and either gore a would-be handler with its horns or maul them with its beak.

By contrast, hadrosaurs were in some ways faster than tyrannosaurs (speeds of ~50 km/h have been suggested) and may have had more endurance. Hadrosaurs like Edmontosaurus are also known to have migrated as much as a modern African elephant, which suggests they were better at the long-distance endurance locomotion necessary for a pack animal.

Another problem with the posture of a Triceratops is it's hard to put a saddle or harness on them. Their backs are strongly sloping and your field of vision could easily be blocked by the large frill and horns. By contrast, hadrosaurs have a nice place to put a saddle at the back of the neck (regardless of whether it's curved and saddle-ready like in some reconstructions or horse-like as in others) which would remain stable even if the animal assumed a bipedal posture.

Ceratopsians also come with some behavioral challenges that make them less appealing candidates for cart animals than. Triceratops is unusual among ceratopsians in that it was rather solitary, whereas other ceratopsians like Centrosaurus would form herds measuring in the hundreds. Even in the cited example you have only three Triceratops at one site, which is a lot lower than is usual for ceratopsians. Solitary behavior means it is a lot harder for humans to impose themselves at the top of the dominance hierarchy and make the Triceratops do what they want. Many, many hadrosaurs, including Edmontosaurus, live in large herds which would make them easier to domesticate.

Hadrosaurs also get a lot bigger than ceratopsians, and therefore can pull bigger loads. The largest known individuals of Edmontosaurus got bigger than T. rex, and Hypsibema and Shangtungosaurus frequently grew to similar sizes.

Ceratopsians also can't swim. Their heads are so heavy they would drown if they went in the water, which means one bad flood and you've lost your draft animal. Compare this with horses or elephants, who can swim. Hadrosaurs are land-adapted animals similar to ungulates, but at least they wouldn't drown if they went through a river.

Realistically speaking, there isn't much a domesticated ceratopsian can do as a draft animal that a hadrosaur couldn't do better, aside from the cool factor and maybe using its horns as a war animal. Ceratopsians may have some advantages in eating higher-fiber woody vegetation.

• This is a very good answer. Jun 25, 2020 at 18:45
• @Renan The biggest thing you'd have to worry about with a hadrosaur is the tail smacking the cart, and you can't dock the tail or else the animal can't walk due to the caudofemoralis attaching there. Maybe have a team of two hadrosaurs on either side like yoked oxen or use large saddle bags similar to what people use with camels. Bonus: hadrosaur skin is very tear-resilient and would make great clothing or bags. Jun 26, 2020 at 13:27

Based on weight and the fact that things don't scale , your (?5-?10 ton) triceratops will have the pulling power of a team of 1-ton heavy horses, so it could pull the largest conventional cart.

Their size creates some interesting issues with harness. Getting them geared up for the ay may require a team of people and some scaffolding.

What makes it more interesting it is metabolism. I would envision them as placid grazers more like oxen, so like oxen or bulls capable of a fast charge at need but generally moving slowly. You may be in for more of an ox-cart lumber than a horse-like brisk trot.

You would also have to consider temperament and intelligence. Obviously they will be bred for domestication, but not all animals have the right qualities to start with. Something that large and powerful will be extremely dangerous if startled or provoked. (What are they like during mating season....?)

Suddenly I see all the advantages of something smaller and horsier.

Pulling a cart might not take full advantage of the triceratops size and strength. Moreover, you have to deal with the logistics of delivering food and water to its current location and removing the resulting fertilizer.

A track or road wide and strong enough for a triceratops, as well as its carts, would be very expensive to build.

I suggest as an alternative a cable railway system. The goods would be moved in trains running on tracks, and pulled by cable loops. The cables would be powered by strategically placed stationary triceratops. The railway system would carry carts full of grain and dried ferns to power the system, in addition to payload. The triceratops locations would be selected for being close enough to a spring or river to keep the triceratops supplied with water.

Because of the locomotive range of a Triceratops, a light cart would naturally bounce up and down (like with horses)1. As a result, we will want to make the base of the cart heavier by using tungsten (a dense material).

Second of all, we will create a cart slightly shorter in height than the Triceratops and equally wide (it will topple over if too tall or wide)2. Since Triceratops is thought to have measured 2.9-3 meters in height, we will create a 2.5 meter tall and wide cart3.

In addition, it would be difficult to turn such a large animal using conventional wheels with tires without causing excessive friction between the tires and the ground. As a result, we will use Mecanum Wheels™ with opposing angles on each side4 to allow for a 360 degree range of motion. (Image source: https://s3files.core77.com/blog/images/lead_n_spotlight/410006_title__47205_te6iK5WZJ.jpg)

The cart will be 10 meters long to allow for a larger volume in carrying capacity without creating excessive length that could lead to collapse. The sides of the cart will be made out of wood to decrease upper cart weight.

As a result, a cart for a Triceratops would look like this:

Finally, we will need a method of attaching the triceratops to the cart. A Triceratops is somewhat similar to an elephant, so we will use a modified elephant harness, but scaled up in size to meet a triceratops' dimensions plus a tail holder. (Image source: https://i.stack.imgur.com/Dm79U.jpg)

An elephant harness is based on an elephant saddle (as shown below), but with wood compartments that attach the saddle to a cart/carriage. (Image source: https://i.stack.imgur.com/xCsoc.png)

P.S. A Triceratops should not carry any more than 1,500 kilograms in its cart as calculated by @Itmauve.