Giganotosaurus

I was justing reading some message on discord in a server for a dinosaur survival game. A guy made a post about how giganotosaurus should face up against Tyrannosaurus. I always tought rex was bigger (in weight since we usually count the weight as the size) but he stated that giga was heavier and bigger then Tyrannosaurus. I was reading some other post on reddit but many people seemed to say giga is bigger but alot of people saying Tyrannosaurus is bigger this got me a bit confused. Since Tyrannosaurus is more robust build and heavier right or am I wrong?

I was wondering if there are any widely agreed upon weight estimates for Giganotosaurus?

I've seen estimates for Giga ranging from 9 tonnes to 13.8 tonnes (Which would place it above T.rex which doesn't make much sense looking at how wider T.rex was) and for T.rex ranging from 8 tonnes to 10 tonnes.

Related to my recent post: T-Rex size comparison to human. Again, all in metric meters (human 1,8m to scale)

Since people asked for another one. Here is Giganotosaurus compared to the TRex specimen of my first post.

Considering Rex on the left side: Sue as an rather complete specimen. Second Goliath as presumably biggest specimen of rex found so far but only fragmentary (femur bone), its size is based on its bigger femur compared to other specimen. Third is a potential well above average rex specimen, which would be rare but within a realistic size range and most likely not close to the potential max size. No specimen that size was found so far.

Giganotosaurus on the right: Basically the same order. First, the rather complete specimen of giga with reliable measurements. Second, another Giganotosaurus specimen that was found really fragmentary (fragmentary jaw bone) about 5-8% bigger than the other one. And again, just as there were most likely well above average sized rexes, a potential above average Giganotosaurus.

Hint: We found many TRex so far. According to since its quite reliable to upscale a Theorpod based on its femur bone (especially when one compares the femur bones of the different rexes we found).

There is only the mentioned rather complete Giganotosaurus and the second potential bigger fragmentary one. Apparently its rather unreliable to upscale a Therpod based on its jaw and less reliable than an upscale based on the femur bone. Meaning its not that certain if the second specimen was really that big. Nevertheless, the Giganotosaurus found were statistically most likely average in size. So the bigger depictions here are within realistic size range.

Also: Measurements of the well preserved Giganotosaurus specimen differ depending on source. E.g. earlier estimates of the bone structure range from 3,5m to 3,6m at the hip. Newer estimates suggest 3,7m or more.

I got the exact size measurements of Sue from the field Museum. On her skeleton you have to add flesh and a rather neutral position (sue is depicted in a crouched position) to get a realistic size she had when still alive.

I have heard some facts or rumors that a Giganotosaurus is bigger than a Tyrannosaurs. Is that True?

I know this comparison has been beaten to death, but recently I was engaged in an argument about these two and I'm having trouble buying the idea that T. Rex would lose.

It got me thinking about a lot of different aspects and I wanted to get together as much of the current data that I can find on both animals and also get some outside opinions on the subject.

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FIRSTLY: SIZE

So this one is tricky for a number of reasons:

We have far less material for Giga than for T. Rex and mass estimates vary widely for both species.

T. Rex: this very recent study from 2025 states "body mass estimates based on volumetric models of adult Tyrannosaurus (~11–12 m in length) range from less than 6 tonnes to over 18 tonnes"

This equates to a range of 4935kg(5.44 tons) to 14,805kg(16.32 tons), with a median of 9870kg(10.44 tons)

Giga: I could not find anything more recent than this study from 2014 which estimates Giganotosaurus within a range of 4759kg(5.25 tons) - 7938kg(8.75 tons), with a median of 6349kg(6.99 tons)

Obviously this study is much older, so I'll include T. Rex's weight range from this same study: 5014kg(5.52 tons) - 8361kg(9.21 tons), with a median of 6688kg(7.37 tons)

This means T. Rex had a 29.4% median increase in weight in the newer study, so I'll give Giga the same treatment, based on the % increase from the current study, making it 8200kg(9.04 tons)

Conclusion: T. Rex had a 1670kg(1.4 tons) weight advantage over Giga

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SECONDLY: BITE FORCE / TEETH

This one is well known, so I'm just going to paraphrase since it's pretty unanimous:

This study from 2010 presents multiple theropod jaw structure mechanics and potential feeding strategies.

T. Rex has bone-crushing jaws, with estimates ranging from 35,000N - 57,000N of force

And Giganotosaurus had a significantly weaker bite with estimates ranging from 13,800N - 19,000N of force

Obviously both animals would've used different techniques to hunt prey, with Tyrannosaurus crushing their prey(which there is countless evidence for) and Giga theorized to slash their prey open with their serrated teeth(which there isn't much evidence for specifically, but is inferred from relatives).

Conclusion: T Rex could crush bone. Giga could slash open. Both could be lethal in the right circumstance.

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THIRDLY: LOCOMOTION / ANIMAL BEHAVIOR

This one seems to be left out of a lot of debates surrounding theropod dinosaurs in general, so here is what I've found:

This study from 2019 states "Tyrannosaurid dinosaurs had large preserved leg muscle attachments and low rotational inertia relative to their body mass, indicating that they could turn more quickly than other large theropods" - meaning they could maneuver better during combat in order to potentially cause more damage and to avoid taking damage.

This theory coincides with the idea that T. Rex regularly hunted and preyed upon one of the most formidable terrestrial herbivores of all time: Triceratops Horridus.

T. Rex co-evolved over millions of years to FIGHT. We have an immense amount of evidence supporting T. Rex and Triceratops fighting, but also T. Rexes fighting one another(see this study from 2022).

T. Rexes seem to have been aggressive and robust predators that could take on and often *did* take on other large aggressive animals while surviving afterwards to heal from their wounds.

This blog from Mark Witton in 2021 suggests Tyrannosaurus and other theropods could head-butt one another during combat. If that was the case, T. Rex's skull was much more robust and therefore would've likely did more damage in comparison to the thinner skull of a Giga.

Speaking of skulls: binocular vision.
During combat between these two, T. Rex would've had better vision. See this summarization of a 2006 study. When compared to Carcharodontosaurus - "Carcharodontosaurus restricted binocular vision to a region only approximately 20° wide, comparable to that of modern crocodiles. In contrast, the coelurosaurs Daspletosaurus, Tyrannosaurus, Nanotyrannus, Velociraptor, and Troodon had cranial designs that afforded binocular fields between 45–60° in width, similar to those of modern raptorial birds" - meaning that during combat it would've had more visual acuity.

According to this study from 2007, states "Powerful forelimbs and a highly mobile neck suggest similarity in the amount of forelimb use between derived carnosaurs and much smaller macropredaceous dromaeosaurs. In contrast, tyrannosaurids and large neoceratosaurians more likely attempted to outmaneuver prey for dispatch by the jaws alone."

This essentially asserts that both animals' necks were specialized for different feeding/hunting habits, but I myself can't determine any particular benefit to either side of the argument from this study and it doesn't include any large Allosauroids to compare to Giganotosaurus. Therefore this study doesn't add much to the debate imho, but could've possibly had an effect in "head-butting" behavior if it occurred.

Conclusion: T. Rex has much more evidence and is studied significantly more, so this one is hard to determine. That being said, based on what data we do have, I personally see a significantly larger amount of adaptations in T. Rex that make it better suited for inter-species combat than what we have evidence for in Carcharodontosaurids in general, let alone Giganotosaurus specifically.

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LASTLY: FINAL CONCLUSION

It seems to me like there is a clear winner.

T. Rex was not only larger, but more robust and could out-maneuver other large theropods. It had better vision, a significantly stronger bite force, and it engaged in inter-species *combat* on the regular, not just hunting prey.

Giganotosaurus has more serrations on its teeth and is about a foot longer, but lacks proper evidence to support any other significant adaptations or beneficial behaviors.

All in all, what we can infer is that T. Rex was bulkier and I think that difference in and of itself is enough.

But I am no expert and I would love for someone to provide more insight on the topic!