Polar Bear vs. Nanuqsaurus hoglundi

[DonaldCengXiongAzuma]

Jan 2, 2020 16:14:06 GMT 5 dinosauria101 said:

DonaldCengXiongAzuma

Comin' up.

Cool. I will be waiting.

[dinosauria101]

DonaldCengXiongAzuma

Here it is. Polar bear is from Wikimedia Commons and is 1.2 meters SH, while Nanuqsaurus is by Nathan E Rogers and 68 cm skull.

[elosha11]

^That seems a bit inaccurate. Polar bears can exceed 1000 pounds, even get up to 1500 pounds, and this theropod is supposed to be around 1200 pounds. So it may have been a bit bigger on average, but not THAT much bigger. That picture makes it look about twice as big as the polar bear. And while nanuq's head was much larger, it didn't dwarf the polar bear's head by that much. See InfinityBlade's excellent first post with diagrams. Different species, but probably around the same proportions for the heads of these two animals.

[dinosauria101]

Well, from what I can tell it would probably work.
Mammals of the Soviet Union, AFAIK, gives the average male polar bear a shoulder height of 1.2 meters and mass of 400-500 kg, and ~550 kg seems to be a severe underestimate for Nanuqsaurus here. Scaling down from Lythronax, its closest relative (which is 6.8 meters and 1.5 tonnes AFAIK), gives 1.03 tonnes, and even scaling from Tarbosaurus (a more gracile relative) gives 914 kg. This tyrannosaur is substantially larger than the vast majority of polar bears.
Regarding polar bear skull size, this source gives about 38 cm for an average male, and the tyrannosaur's skull is about 68 cm based on what Infinity Blade posted - that seems fairly coherent with my chart.

[elosha11]

Not sure where you're getting the weight estimates for the dino. InfinityBlade's initial post said around 1000 pounds but the hyperlink for his sources aren't working. Did Nathan Rogers provide a weight estimate, and if so, what was it the basis? Even if the dino was a ton, a big polar bear 1200-1500 pounds, would not be as dramatically smaller as this pic. Also the dino's head appears to to over twice as long as the polar bear's (admittedly just my eyeballing it), whereas the length estimates you provided would suggest it was less than twice as long.

I think if you scaled this polar bear up by 25-35%, you'd get a much better depiction.

[dinosauria101]

Jan 2, 2020 21:36:04 GMT 5 elosha11 said:

1: Not sure where you're getting the weight estimates for the dino.
2: InfinityBlade's initial post said around 1000 pounds but the hyperlink for his sources aren't working.
3: Did Nathan Rogers provide a weight estimate, and if so, what was it the basis?
4: Even if the dino was a ton, a big polar bear 1200-1500 pounds, would not be as dramatically smaller as this pic. Also the dino's head appears to to over twice as long as the polar bear's (admittedly just my eyeballing it), whereas the length estimates you provided would suggest it was less than twice as long.

1: This is from scaling down from relatives. The lower one was scaling down from Franoys' mass estimate of 5 tonnes for a 10.57 meter Tarbosaurus, and the higher was from scaling down the (oversized) mass estimate for Lythronax, which was 8 meters and 2.5 tonnes, to what Theropod says is 6.8 meters. 
2: 450 kg is faaaar too gracile for a 6 meters tyrannosaurine. Scaling that up to 12 meters gives 3.6 tonnes, and most tyrannosaurids are 7-8 tonnes at 12 meters.
3: No, as I said this is scaling from relatives
4: Looks aren't necessarily everything. Bear in mind (ha!) that the bear would have denser bones due to its frequent swimming habits, while theropods like Nanuqsaurus are pneumatized (partly air). Not to mention there is a hypothetical feather coating on Nanuq that would make it look larger. As for head length, I measured from the ear to the the nose for the bear, and this is a bit over half the length of the dino's skull.   

[elosha11]

Ok, but I note your using an average size bear. Why don't you try to scale it up to max size, around 1500 pounds and see how that appears? I still don't think bones and feathers alone can make up from this size discrepancy. Two animals that greatly overlap in size should visually seem closer in appearance than this.

[dinosauria101]

elosha11
Here it is. I replaced the Nanuq with Prehistoric Wildlife's for ease of scaling.
The bear is now ~133 cm SH and would be about 700 kg.

[DonaldCengXiongAzuma]

Jan 2, 2020 21:49:22 GMT 5 dinosauria101 said:

Jan 2, 2020 21:36:04 GMT 5 elosha11 said:

1: Not sure where you're getting the weight estimates for the dino.
2: InfinityBlade's initial post said around 1000 pounds but the hyperlink for his sources aren't working.
3: Did Nathan Rogers provide a weight estimate, and if so, what was it the basis?
4: Even if the dino was a ton, a big polar bear 1200-1500 pounds, would not be as dramatically smaller as this pic. Also the dino's head appears to to over twice as long as the polar bear's (admittedly just my eyeballing it), whereas the length estimates you provided would suggest it was less than twice as long.

1: This is from scaling down from relatives. The lower one was scaling down from Franoys' mass estimate of 5 tonnes for a 10.57 meter Tarbosaurus, and the higher was from scaling down the (oversized) mass estimate for Lythronax, which was 8 meters and 2.5 tonnes, to what Theropod says is 6.8 meters. 
2: 450 kg is faaaar too gracile for a 6 meters tyrannosaurine. Scaling that up to 12 meters gives 3.6 tonnes, and most tyrannosaurids are 7-8 tonnes at 12 meters.
3: No, as I said this is scaling from relatives
4: Looks aren't necessarily everything. Bear in mind (ha!) that the bear would have denser bones due to its frequent swimming habits, while theropods like Nanuqsaurus are pneumatized (partly air). Not to mention there is a hypothetical feather coating on Nanuq that would make it look larger. As for head length, I measured from the ear to the the nose for the bear, and this is a bit over half the length of the dino's skull.   

Glad we can agree the polar bear has denser bones here ☺️ and thank you for the size comparison between the two animals.

Looks like the nanqusaurus weight seems to be underestimated right?

[dinosauria101]

Jan 3, 2020 1:39:56 GMT 5 DonaldCengXiongAzuma said:

Jan 2, 2020 21:49:22 GMT 5 dinosauria101 said:

1: This is from scaling down from relatives. The lower one was scaling down from Franoys' mass estimate of 5 tonnes for a 10.57 meter Tarbosaurus, and the higher was from scaling down the (oversized) mass estimate for Lythronax, which was 8 meters and 2.5 tonnes, to what Theropod says is 6.8 meters. 
2: 450 kg is faaaar too gracile for a 6 meters tyrannosaurine. Scaling that up to 12 meters gives 3.6 tonnes, and most tyrannosaurids are 7-8 tonnes at 12 meters.
3: No, as I said this is scaling from relatives
4: Looks aren't necessarily everything. Bear in mind (ha!) that the bear would have denser bones due to its frequent swimming habits, while theropods like Nanuqsaurus are pneumatized (partly air). Not to mention there is a hypothetical feather coating on Nanuq that would make it look larger. As for head length, I measured from the ear to the the nose for the bear, and this is a bit over half the length of the dino's skull.   

Glad we can agree the polar bear has denser bones here ☺️ and thank you for the size comparison between the two animals.

Looks like the nanqusaurus weight seems to be underestimated right?

Yes, that's true - in general, theropods at ~6 meters aren't really 500 kg as is often stated.
For instance, Shaochilong, Concavenator, and Nanuqsaurus, at 6, 6.2, and 6 meters respectively are about 864 kg, 921 kg, and 1 tonne scaling from relatives respectively. Not the often quoted 500 kg.

As for the polar bear bone density thing, I learned it from you. You truly are a bear expert!

[Infinity Blade]

I edited the OP to better fit our relatively new format for these threads. I also found that a total body mass of ~900 kg seems to be seen as plausible for Nanuqsaurus by what seems to be a rather rigorous source for dinosaur body mass (it's got Asier Larramendi as one of the authors, fwiw), so I've incorporated that into the OP. Of course, any arguments against this are welcome.

EDIT 11/12/2021: Looks like I've got one myself. The holotype of Nanuqsaurus has been interpreted as belonging to an immature animal by recent research. Undescribed teeth and postcranial remains suggest adult animals closer in size to Albertosaurus. Albertosaurus, for the record, weighed somewhere around 2.6 tonnes.

"We note that other Prince Creek Formation tyrannosaurid material in the UAMES collection do not support the assertion that Nanuqsaurus is a diminutive, small-bodied tyrannosaur. Rather, adult-sized teeth and isolated postcranial elements suggest an adult body size more closely comparable to other North American tyrannosaurid taxa, such as Albertosaurus sarcophagus. As such, we interpret small tooth crown size in UAMES 17610 to be reflective of an early ontogenetic state and not related to small adult body size."

www.sciencedirect.com/science/article/pii/S0960982221007399?casa_token=aZuCB3PWgLUAAAAA:UktWvYqw3n2RqIqeRiPQfil6lfIgvQlTrsGO4PXRcyTOoJQlbFM7RhEn8mMXbatuAKI4iqLHqQ

While I stand by my opinion backing a robust skulled tyrannosaurid against a bear even at hypothetical parity, this is probably not a parity fight. Forget polar bears, this dinosaur could tear apart a rhinoceros.

[dinosauria101]

I think 900 kg seems reasonable - not too far off from what I got with the scaling. The weight for the bear of course is pretty good.

[Verdugo]

Jan 2, 2020 22:54:44 GMT 5 dinosauria101 said:

Here it is. I replaced the Nanuq with Prehistoric Wildlife's for ease of scaling.
The bear is now ~133 cm SH and would be about 700 kg.

The illustrations from Prehistoric Wildlife are usually oddly proportioned so it's not a source i would recommend using for making size comparison. Nanuqsaurus is very fragmentary, only represented by fragmentary cranial materials with no post-cranial materials IIRC, so we know little about its actual proportions. I think it's most appropriate that you just take a rigorous skeletal drawing from more well-known Tyrannosaurids, and scale it down/up to around 6 m long. I would recommend taking Frannoys's Daspletosaurus and shrinking it down to around 6 m in length to get Nanuqsaurus. Daspletosaurus is rather short-legged by Tyrannosaurid's standard so i think its proportion would be reasonable for a Tyrannosaurid living in cold environment.


Also, could you use this Polar bear's skeletal drawing instead?

I would love to see how their skeletons are compared to one another. Thanks in advance

[dinosauria101]

Verdugo , you do have a point there - PW, while there may be those handy scalebars, is probably not the best; no telling what it's based on.
As for the new skeletals, I used Hartman's Lythronax scaled to the estimated ~68 cm for Nanuq as Lythronax appears to be the closest relative. The bear is scaled to about 133 cm SH and ~700 kg while the tyrannosaur is ~68 cm skull length and ~1 tonne.