What is the largest an animal can be?

[Chronos]

Quoth Iggy:

The same reports notes that some shallow water sponges could live to 2300 years, thought dating them is difficult.

Then I guess I won’t be needing these flowers and box of chocolates.

[DrDeth]

@Chronos

Then I guess I won’t be needing these flowers and box of chocolates.

snort, guffaw…wipes keyboard and screen.

[Weisshund]

@cjackson

I know the blue whale is the largest known animal to have existed on Earth, but can animals conceivably grow larger, or is that pretty much the largest animal you can expect to find in the universe?

Can not answer this question
We only know somewhat definitely about life on earth.

On earth life does have size constraints, which vary with the physical body design and the design of its supporting systems.
(Referring to only an individual being, not a composite)

For example, you can not have a 100 foot tall insect, the exoskeleton nor the breathing mechanism can support that size, not on this planet.

There are many many things that dictate max size
distribution of nutrients to the entire body, breathing, moving, are not even a scratch in the list.

In the Universe?
Can not even begin to answer, what environment in the universe, what composition is the life form, how does it function, how does it live, where does it live.
And then after answering that kind of stuff, since we don’t know any other life forms, we can only give neat theories, but no real answer.

[TSBG]

Thank you all for an interesting discussion, but special Thanks to Colibri. I think that as a scientist you have a real gift for communicating in vernacular. Do you write books? If not you should, I’d read them.

[Leo_Bloom]

Wiki on megafauna, if it hasn’t been posted upthread already.

[Atamasama]

@TSBG

Thank you all for an interesting discussion, but special Thanks to Colibri. I think that as a scientist you have a real gift for communicating in vernacular. Do you write books? If not you should, I’d read them.

He has written some Straight Dope articles.

I’d be interested in books too, he really is a great communicator.

[Colibri]

@TSBG

Thank you all for an interesting discussion, but special Thanks to Colibri. I think that as a scientist you have a real gift for communicating in vernacular. Do you write books? If not you should, I’d read them.

Thank you. I am a professional science writer and exhibition curator. As mentioned, I have written a number of Straight Dope staff reports, a few of which were republished here. I have published several books on the birds of Panama.

[Filbert]

@DrDeth

I agree, and there’s no reason one of them couldn’t be longer than a a blue whale.

Bootlace worms may well already get longer than blue wales (they’re a bit stretchy to get accurate measurements), and they’re definitely one organism.

[Gunslinger]

@Kamino_Neko

including the largest land animals ever (the high weight estimate* for the largest of them, Argentinosaurus, is about even with a blue whale)

Largest in length, maybe, but that weight estimate is way off – that was calculated based on it being the density of an elephant or some such, when it’s actually even more hollow-boned than a goose.

Also, “dinosaur” is a loose term. T. rex is way closer in every metric but size to those little sparrows in your yard than to Stegosaurus.

@TriPolar

There are masses fungi and trees that are part of clonal colonies.

There’s a humongous fungus among us. Also one bigass aspen tree grove, iirc, with lots of shoots from a single root system.

@Silver_lining

In the water, larger animals such as Blue Whale can be supported.

When you get very big, gravity can be the enemy. Things weigh a lot less in water.

However, if you want to talk theory, it is possible to have bigger ( but perhaps not more massive in weight ) type of floating animal that is lighter than say a thick/dense form of gas on a planet or moon’s atmosphere.

Most critters are about the same density as a sack of muddy water, because that’s essentially what were are – you and I, for example, are 70+ percent water. The square-cube law defines an upper limit for things that walk – get much bigger than the biggest sauropods and the leg bones have to be unreasonably big to carry the weight, so the 50-Foot Woman and giant-bug movies like Them! are right out – but whales get a break, because they’re near enough the same density as their medium to not have to deal with gravity, then it’s just air/food supply that limits size. (And, I guess, water pressure, that tangent to gravity.) A jellyfish-like critter floating among the upper clouds of a gas giant? The only limits are respiration and prey.

@Filbert

Bootlace worms may well already get longer than blue wales (they’re a bit stretchy to get accurate measurements), and they’re definitely one organism.

Mass is more the issue in this discussion, though. Or I guess acreage, if you’re willing to consider my posited living Zeppelins. Being a ribbon is just cheating the Guinness Book length category, y’dig?