Simple Question....Simple Answer? (2 Viewers)

jpoyner

Well-known member

• Jul 27, 2004

• #1

Got asked this today by a non-birding friend............

"Why do birds float and animals swim"? What's the "simple" answer?

JP :h?:

 

V

very boring banned member

New member

• Jul 27, 2004

• #2

Mammalia have heavier bones than Aves.

 

jpoyner

Well-known member

• Jul 27, 2004

• #3

She says......"but surely Geese are pretty heavy birds......." I'm giving up :h?:

 

E

Edward woodwood

Member

• Jul 27, 2004

• #4

simple answer these days is

'go and watch tv or something'

but to be serious, Karwin is basically right - but it's density rather than weight; penguins for example have denser bones and so can float lower in the water. Bird bones have a 'bony foam' or air sacs in them that aid bouyancy

interestingly, so did lots of dinosaurs and recent work has suggested that even some of the very biggest dinosaurs (Sauropods i think they're called) could float......

 

birdman

Орнитол&

• Jul 27, 2004

• #5

jpoyner said:

She says......"but surely Geese are pretty heavy birds......." I'm giving up :h?:

Click to expand...

Just to restate Karwin and Tim in a different way... and hopefully give you a "big bird" argument. Just been watching "Life of Birds" and Sir David had a Golden Eagle on his wrist.

As he points out, and Golden Eagle is about the same size as a Bulldog, but there's no way he could've held a Bulldog in the same way, as it weighs 4 times as much.

 

birdman

Орнитол&

• Jul 27, 2004

• #6

If that fails, you could always say that bird's feathers repel water with exactly the same force as gravity attracts the whole bird - ie 1-g... and so that's why birds just balance on the surface of any stretch of water...

 

A

Anthony Morton

Well-known member

• Jul 28, 2004

• #7

Could the bird's buoyancy be improved in the short term by the amount of air trapped between its feathers (which are kept water-resistant by preening) and its skin?

 

Michael Frankis

conehead

• Jul 28, 2004

• #8

Anthony Morton said:

Could the bird's buoyancy be improved in the short term by the amount of air trapped between its feathers (which are kept water-resistant by preening) and its skin?

Click to expand...

Yes, quite considerably.

That's why cormorants don't have waterproof feathers - their lower buoyancy as a result of not trapping air enables them to dive more efficiently

Michael

 

weather

Pirate name: Poncy Henry Goodfellow

• Jul 28, 2004

• #9

jpoyner said:

Got asked this today by a non-birding friend............

"Why do birds float and animals swim"? What's the "simple" answer?

JP :h?:

Click to expand...

They most be WITCHES!!!....Burn 'em.

Mike

 

D

Dave B Smith

Well-known member

• Jul 29, 2004

• #10

Or the really simple answer, Birds because they can, animals because they can't