Dinosaur scale thread

[DinoToyForum]

I've created a Dinosaur Toy Scale Calculator on the DinoToyBlog: https://dinotoyblog.com/dinosaur-toy-scale-calculator/

Just input the length of the toy (in cm or inches) and the animal (in metres or feet) and it outputs the scale. It will also work if you input measurements for a particular body part or measurement, say, the skull (both toy and animal).

It uses the formula of T @therizinosaurus and @Gwangi. For simplicity I've set it to round up or down to a full number (i.e. 0 decimal places). I'm thinking this will be particularly helpful for reviewers now that we have a scale category on the blog, but anyone can use it.

[Gwangi]

That's a handy tool to have. That's the formula I've used for every review on both blogs. Not always body length though. I've used it for skull length, wingspan, and shoulder height too. Depending on what I'm reviewing.

[DinoToyForum]

That's a handy tool to have. That's the formula I've used for every review on both blogs. Not always body length though. I've used it for skull length, wingspan, and shoulder height too. Depending on what I'm reviewing.

Yeah, I put "length of the animal" and "length of the toy" in the instructions for simplicity, but I could change that to "length of the animal (or a specific dimension of the animal)", and "length of the toy (or the same specific dimension of the toy)". It can be any part or dimension so long as we measure like for like.

I doubt anyone would input, say, the length of the animal and the length of the toy's skull, which would give the wrong result. Similarly, if measuring a part of the animal it might be easy to mistakenly input in cm/inches rather than m/ft, which would also give a wrong result. But I doubt that would happen very often, and there's no way to control for mistakes like that anyway.

[Ikessauro]

Am I correct to assume I should measure a figure following the animal's vertebral column to get a correct scale?

[DinoToyForum]

Am I correct to assume I should measure a figure following the animal's vertebral column to get a correct scale?

Yes, the full length measurement should reflect a neutral symmetrical pose, from snout to tip, so if the toy has the neck or tail turned to the side, that has to be taken into account. But the measurement shouldn't represent the length of the spine as if it was stretched out in a completely straight line (dorsoventrally as well as mediolaterally), unless it's an animal with a more or less completely straight spine, like a snake or plesiosaur.

The scale is always going to be approximate anyway to account for variations in posture (of both the toy and the reconstructed animal) and variations in the full length estimates.

[Stunt_Kitty_Films]

I've recently started examining the scale of the figures in my collection. Rather than using individual measurements, I'm using an overall approach by overlaying photos on top of scale drawings.

[DefinitelyNOTDilo]

That is quite a neat approach! I assume you're photographing them alongside an object of a known scale.

[Sim]

But the measurement shouldn't represent the length of the spine as if it was stretched out in a completely straight line (dorsoventrally as well as mediolaterally), unless it's an animal with a more or less completely straight spine, like a snake or plesiosaur.

D @Dinoguy2 has said that prehistoric animal length estimates tend to be of the animal's bones put in a straight line, so that should be how the figure's vertebral column should be measured too.  Is that incorrect?

[DinoToyForum]

But the measurement shouldn't represent the length of the spine as if it was stretched out in a completely straight line (dorsoventrally as well as mediolaterally), unless it's an animal with a more or less completely straight spine, like a snake or plesiosaur.

D @Dinoguy2 has said that prehistoric animal length estimates tend to be of the animal's bones put in a straight line, so that should be how the figure's vertebral column should be measured too.  Is that incorrect?

In a straight line mediolaterally, yes. But dorsoventrally as well, even if the animal could or would never adopt that pose in real life, or measured obliquely along the spine from, say a head in high position to a tail in a low position? Wouldn't that be misrepresenting (inflating) the actual length of the animal?

Anyway, it doesn't really matter, so long as the person calculating the scale is comparing like for like.

[Sim]

I think Dinoguy2 mentioned that the life position of the bones of dinosaurs couldn't be fully known, particularly for example the position of the neck.  So the length would be measured as if the animal's bones were in a straight line on the ground.  It would be increasing the length of the animal from the length when it was alive, but it would be consistent with the length estimates I tend to see for dinosaurs compared to size charts with rigorous reconstructions of the animal.  The length estimates tend to be longer than the reconstructed animals.

[Stunt_Kitty_Films]

That is quite a neat approach! I assume you're photographing them alongside an object of a known scale.

I use some of the drafting-like features of Blender 3D app to size the skeletal drawing and photo in conjunction to each other based on the scale bar. I then scale up the photo of the figure to match the skeletal drawing, thereby determining the scale.

[DinoToyForum]

I think Dinoguy2 mentioned that the life position of the bones of dinosaurs couldn't be fully known, particularly for example the position of the neck.  So the length would be measured as if the animal's bones were in a straight line on the ground.  It would be increasing the length of the animal from the length when it was alive, but it would be consistent with the length estimates I tend to see for dinosaurs compared to size charts with rigorous reconstructions of the animal.  The length estimates tend to be longer than the reconstructed animals.

Yeah, the 'length' will be seriously inflated if measured that way. There's a big difference between the length of the animal from front to back, and the length of the vertebral column + skull. Here's a diagram I created to compare three different ways of measuring the 'length' of a familiar modern animal.



A is the length of the animal from front to back.
B is the length of the spine + skull, as measured in a straight line.
C is the length of the spine + skull, as measured along the dorsoventral curvature.

The numbers in black give the significantly different lengths of the lines (in pixels): C > B > A.

I understand the reason for calculating C for a scientific description, but we have to be careful not to conflate that measurement with the front to back length of the animal (A). It might work out for some groups, but it will be way off for others. In the giraffe, C is a whopping 40% longer than A. So, if length estimates for dinosaurs (on, say, Wikipedia) are uniformly calculated by method C, we need to treat the measurements with caution, and measure our toys using the same metric (if that's even possible, since the 'spine' measurement is inside the toy). The best we can measure accurately would be B. If they are not uniformly calculated by method C or the method is not made explicit, then we need to treat our scale calculations with caution.

[andrewsaurus rex]

Agreed.  I usually find on good quality illustrations, that while the description may say '80 feet long', if you look at the accompanying illustration, which includes a scale bar, the 'front to back' length is normally much less, indicating that the 80 foot figure is measured along the curvature..  At least that's what I usually see in Wikipedia articles.

With mammals the norm is to quote the 'head body' length, which ignores the tail.  Obviously with prehistoric reptiles (and extant ones) that is not as useful a dimension to quote.

[DinoToyForum]

Related thread: https://dinotoyblog.com/forum/index.php?topic=9457.0

I may need to add a disclaimer to the Dinosaur Toy Scale Calculator!

@Sim, please can you direct me to D @Dinoguy2's discussion of how dinosaur lengths are calculated? Is it on the forum or elsewhere?

[andrewsaurus rex]

Since body posture will play a big factor in the natural length of the animal, especially sauropods, a better approach might be trunk length (base of the neck to the start of the tail) which is fairly static and thus not open to as much interpretation.  Problem is many remains are incomplete of course, making perhaps vague estimates necessary.  But it would allow for fairly accurate scale drawings and models to be constructed.  ie if the head, neck, limbs and tail are represented proportionally to the trunk, then the result must be the size the animal was; the only variations would be because of the poses selected by the various illustration/model creators, but the dimensions of each body part would still be the same, regardless of pose.

I also find hip height is a good standard to go by as it is fairly static as well, although a uniform leg position would have to be standardized. eg standing at rest, not walking or bending/crouching

[Concavenator]

I've created a Dinosaur Toy Scale Calculator on the DinoToyBlog: https://dinotoyblog.com/dinosaur-toy-scale-calculator/

Great idea!! 

[andrewsaurus rex]

Another problem with assessing scale in models/toys is that you have to ensure the model represents the animal well proportioned.  Many toys have features exaggerated or not big enough and that can really throw off the scale calculation.   It happens all the time with Mattel figures, for example.

Such as the recent Elasmosaurus review.  The scale is noted as 1/27.  But since the neck is way too short proportionately, that isn't really the scale of the figure.  The neck should be much longer, and if it were,  the figure would be much longer overall and this would reduce the scale of the figure.  So the Mattel figure is more like 1/22 scale with a neck that is way too short.  But the body (base of neck to start of tail) is about 1/22 scale.   Since most Mattel figures are proportioned wrong, determining scales for them is really tough.

Another example is the Epic Roarin' Trex, which I love.  The head and legs are 1/18, the body and tail are about 1/22 and the arms are about 1/15 (I won't even talk about the feet).  So what scale is it?   I use it for 1/18 scale because of the head being correct.  But strictly speaking it isn't any scale really....it's a mish mash of scales.

[Sim]

@DinoToyForum, Dinoguy2's comments on measuring dinosaurs were on this forum.  I've currently only found two threads where he talked about it, first is this one: https://dinotoyblog.com/forum/index.php?topic=5199.0  The most relevant posts are #6, #15 and #18.  In the thread @Doug Watson said that in palaeontology length is measured as if the bones were in a straight line on the floor and some palaeontologists told him it was the norm...

There's also this thread: https://dinotoyblog.com/forum/index.php?topic=3571.0  The most relevant post is #8.

I haven't been able to find the part about neck posture, it must have been in another thread, but as an example, the Haolonggood Spinosaurus and PNSO 2023 Spinosaurus are in the same scale (1:35), but the posture of their neck is very different, contributing to different lengths for the two figures.

[DinoToyForum]

@DinoToyForum, Dinoguy2's comments on measuring dinosaurs were on this forum.  I've currently only found two threads where he talked about it, first is this one: https://dinotoyblog.com/forum/index.php?topic=5199.0  The most relevant posts are #6, #15 and #18.  In the thread @Doug Watson said that in palaeontology length is measured as if the bones were in a straight line on the floor and some palaeontologists told him it was the norm...

There's also this thread: https://dinotoyblog.com/forum/index.php?topic=3571.0  The most relevant post is #8.

I haven't been able to find the part about neck posture, it must have been in another thread, but as an example, the Haolonggood Spinosaurus and PNSO 2023 Spinosaurus are in the same scale (1:35), but the posture of their neck is very different, contributing to different lengths for the two figures.

Thanks for digging out those conversations.

The take-home message for me was this:

"In palaeontology length is measured as though the skull and vertebrae were laid out on the floor in straight  line"
This is usually true but not always, and I challenge you to find a single paper that explains which way they did it!

So, I think we just have to regard the scales we calculate as approximate, no matter how we approach it there is so much room for error.

[Gwangi]

I usually measure down the midline of the back and account for the various curves in the spine. But yeah, it's gonna be approximate any way you do it. The lengths of the animals themselves are approximate.