Can Dragons Float?

[Tim the Enchanter]

A somewhat random question, but a question nonetheless. Anyway, I'm wondering whether dragons can float or not. Do you think that dragons are too heavy and dense to float in water, ensuring that they drown; or do you think that they would be light and less dense because they can fly, and thus would float in water?

The reason why I ask is I'm trying to decide how the Norwegian Ridgeback goes about hunting aquatic prey, a trait unique to the species according to Fantastic Beasts and Where to Find Them. If dragons are too dense and would drown in water, I think the Norwegian Ridgeback would hunt aquatic life by using its talons to pluck fish that are too close to the surface out of the water, much like an Osprey would. On the other hand, if dragons can in fact float, I'm thinking that the Norwegian Ridgeback could dive straight into the water (like a cormorant) and kill its prey by shooting jets of hot bubbles, i.e. breathing fire underwater.

So, any thoughts on whether dragons can float or not? Any suggestions on how the Norwegian Ridgeback hunts fish, seals, and other marine animals?

Tim the Enchanter

[OliveOil_Med]

Hm, I know there is a mathematical formula relating relitive sive to weight to calculate density and figure out whether an object is capable of floating. Sadly, I am not a math person, and I do not know exactly what that formula is. Hopefully some of the site's math geniuses will, or else you will just have to look it up on your own. It shouldn't be that hard to find.

[Inverarity]

Most reptiles can swim. Flying reptiles would probably be even more bird-like, with less dense bones and bodies. So I'd say the answer is yes.

[OliveOil_Med]

Yes, lizards can swim. But what I am wonder is whether or not dragons have too much density to be able to float in water. Remember, they do way several tons, and if their body density is too great, they would sink.

[x_GinnyPotter_x]

interesting question. Personally, I can't see a dragon floating on the water's surface and paddling around like a duck.

But more reasonably, I think depends on how they are able to fly. Birds can fly because they're lightweight and have hollow bones. Dragons certainly aren't lightweight, and I can't imagine hollow bones would work because of the amount of muscle dragons have. They have huge bodies that require a strong support to hold up. I'd think dragons are able to fly based more on pure strength and magical properties than physical adeptations similar to birds. Same with Threstrals - their body type wouldn't allow hollow bones, and I can't see them floating, either. More likely magical ability factors in to help them fly.

Also, I just pulled out my copy of DH to check and make sure the dragon from Gringotts didn't float in the lake after the escape. No mention of it.

It was already fifty feet away, swooping low over the lake to scoop up water in its scarred snout... the dragon flew on, its wing beating hard, and landed at last on a distant bank.

But then again, it never said if that dragon was a Norwegian Ridgeback, so that may not mean anything.

I'd imagine the Norwegian Ridgeback would hunt water-prey like an Osprey, grabbing seals and such out of the water with its huge talons. Maybe even small dolphins, since little fish might be a bit hard to grasp.

Hope that might help!
--Kayla

[Inverarity]

Yes, lizards can swim. But what I am wonder is whether or not dragons have too much density to be able to float in water. Remember, they do way several tons, and if their body density is too great, they would sink.


Density has nothing to do with weight.

Whales weigh several tons, too.

[Karaley Dargen]

They probably can fly because of ther huge wings and magic - so they probably can float by magic, too. I can imagine a dragon diving fast, with its wings close to its body, and then ascending, maybe even by beating its wings... It's much cooler anyway ;)

And I think the point about whales is a very good one. Also, ships. There are ships that weigh several ten thousand tons, and they still stay afloat, because they're shaped to displace the weight of more water than they weigh themselves.
To drift on the water surface, the dragon would just spread out its wings and, thus producing a larger.. base area (?) I think it would stay afloat easily.

I think I would combine the two. If there's something close to the water surface, the dragon would just pick it up with its claws or jaw, and if it's hungry and can't find anything, it goes diving.

How much exactly do dragons weigh anyway?

[Halgy]

Density has nothing to do with weight.

Whales weigh several tons, too.
Acutally it has something to do with weight, but I'll take your point.

There are very few large animals that can't float (since sinking is a distinct evolutionary disadvantage). I'd imagine that dragons can float. Yes, they weigh a lot, but they are also huge (volume wise).

Large weight/large volume = possibly buoyant.

Plus, they are magical; they can pretty much do anything you want (so long as J.K.R. hasn't said couldn't).

[Tim the Enchanter]

I'm glad to see so much interest given to a thoroughly useless question! Perhaps the Ministry of Magic should conduct some experiments - dropping dragons into lakes and seeing if they float or not...

However, there seems to be a somewhat vague consensus that dragons can float, for reasons that are unclear. Even so, I think that I would go with Kayla's suggestion and have the Norwegian Ridgeback hunt by plucking fish out of the water like an Osprey, rather than diving after them.

But now that we seem to think that dragons can float, here's another question:

Do you think dragons can take to the air from the water, or do you think they'd need to swim to land and dry off first?

Personally, I think that if dragons are buoyant, they'd float mostly submerged like a crocodile, rather than floating on top of the water like a duck. Since most of the body is underwater, it would be difficult for the wings to create enough lift to drag itself out, but that's just what I think.

Tim the Enchanter

[Karaley Dargen]

Don't forget Hippo-style. They walk underwater, and basically jump to get up again.

[Tim the Enchanter]

Don't forget Hippo-style. They walk underwater, and basically jump to get up again.

True, but hippos cannot fly. So, do you think dragons could launch themselves with enough force to get airborne?

Tim the Enchanter

[Inverarity]

Do you think dragons can take to the air from the water, or do you think they'd need to swim to land and dry off first?

Personally, I think that if dragons are buoyant, they'd float mostly submerged like a crocodile, rather than floating on top of the water like a duck. Since most of the body is underwater, it would be difficult for the wings to create enough lift to drag itself out, but that's just what I think.


I agree. Birds that can take off from the water are buoyant, and float on the surface like corks.

Also, we've discussed in a previous thread the implausibility of dragons flying in the first place. But unless you assume that the same magic that lets them fly allows them to simply ignore physics altogether, a dragon just doesn't seem likely to be able to generate the sort of lift by flapping its wings rapidly that would pull its body out of the water without any other upward force. Besides the likelihood that, unlike a bird, it starts out partially submerged, the water will also act as a drag.

A dragon could only jump if it's in water shallow enough to reach the bottom.

[OliveOil_Med]

I just wish I knew the actually mathematical formula for figuring out buoyancy. I know there are several large animals that can float, but other physical factors go into that besides weight. There is probably little chance, however, of being able to look up the physiology of dragon, though.

[herm_own_ninny13]

Density formula is mass/volume. If something is less dense than water, it will be able to float.

But, I digress. It would be SO much cooler for a dragon to dive into the water and dive back out and fly away.

[x_GinnyPotter_x]

Originally Posted by Tim the Enchanter
Do you think dragons can take to the air from the water, or do you think they'd need to swim to land and dry off first?

Personally, I think that if dragons are buoyant, they'd float mostly submerged like a crocodile, rather than floating on top of the water like a duck. Since most of the body is underwater, it would be difficult for the wings to create enough lift to drag itself out, but that's just what I think.

Hmm... I agree, croc-style would seem the most logical style of floating/swimming for a dragon. They seem fairly similar enough to make that assumption, so I can see a dragon swimming about the same way - they have long tails that could probably be used for propelling/steering if needed, so once in the water they could dive under and chase and catch their prey. Though I'm not sure if dragon's tails would be well-designed for this use... perhaps Norwegians have a specific adaptation of their tails for this, sonce they are the only species to hunt water animals. I doubt a dragon would want to use its wings much in water, since the drag from the water might be a bit much for them to handle. They might be useful for steering, though.

As for exiting the water, I also agree with Tim... while the wings have enough strength to get a dragon off the ground, I don't think they would be able to overcome the weight of the water in addition, at least not alone. Maybe the could propell themselves out - start deep and use speed/acceleration to get them out of the water and back into the air so they can fly. (This might also be nessecary in the absence of near-by land, like in oceans or large lakes) Since they don't exactly have feathers, I don't think they'd need to dry off first. But they probably would need to get back to land or jump out of the water in order to take flight again.

--Kayla

[Tim the Enchanter]

Having asked such a random question about the buoyancy of dragons, I have some more questions:

Charlie Weasley "studies dragons in Romania" - what exactly does that mean? Does Charlie just observe and take notes, like wizards presumably have done for the centuries that dragons have been kept away from Muggle eyes? Or could these dragon researchers be performing experiments on dragons, like dropping them in lakes to see if they float or not?

Also...

The Norwegian Ridgeback is so named because of the sharp ridges on the back of its spine. What is the purpose of this feature? Could it have any use for the Ridgeback's aquatic/terrestrial feeding habits?

Tim the Enchanter

[Halgy]

Charlie Weasley "studies dragons in Romania" - what exactly does that mean? Does Charlie just observe and take notes, like wizards presumably have done for the centuries that dragons have been kept away from Muggle eyes? Or could these dragon researchers be performing experiments on dragons, like dropping them in lakes to see if they float or not?

I always took this to mean that he was studying how to handle and care for them, rather like a super Care of Magical Creatures class. It's possible that they did studies, but mostly I figure he just learned now to be around them and not be killed.

The Norwegian Ridgeback is so named because of the sharp ridges on the back of its spine. What is the purpose of this feature? Could it have any use for the Ridgeback's aquatic/terrestrial feeding habits?

The first thing that comes to mind would be ridges for protection. I don't know what would eat a dragon, but some dinosaurs had them too. If you want to go that far into it, they could be a left-over defense mechanism that helped them ward off T-Rexes and such, and they simply haven't evolved since.

[OliveOil_Med]

I finally found the equation I was looking for! The one to figure out rlative density of an object!

Relative Density=substanceX/referenceX
The substance being actual weigh and the reference being the overall volume of the object.

In order to figure out whether or not an object can float, you calculate the relative density of the object and compare it to the density of water. If it is greater than water's density, it will sink, but if it is less, the object has boyancy, and it will float.

[Tim the Enchanter]

I finally found the equation I was looking for! The one to figure out rlative density of an object!

Relative Density=substanceX/referenceX
The substance being actual weigh and the reference being the overall volume of the object.

In order to figure out whether or not an object can float, you calculate the relative density of the object and compare it to the density of water. If it is greater than water's density, it will sink, but if it is less, the object has boyancy, and it will float.

Thanks for the equation, but since nobody here knows how much a dragon weighs or how much volume it has, I'm afraid we're stuck.

But there seems to be a general consensus that dragons can in fact float.

Tim the Enchanter