Current Events > a picture of a toucan

(+) Yeah! (+)

A toucan's beak has a rich supply of blood vessels running along its surface so the bird's bill is suited to act as a means of radiating heat to keep the core temperature of the body stable the bill also accounts of between 30 and 50 per cent of the bird's surface area.

In case you guys ever wondered why their beaks are so big. I knew of this a while ago, but it's still a cool fact to know about them and to explain their ginormous beaks.

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Rainbow_Dashing posted...

the bill also accounts of between 30 and 50 per cent of the bird's surface area

wait that's. probably not true? >_> i would assume feathers n shit give you a LOT of surface area per volume

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I follow two YouTubers who own toucans lol.
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Choco posted...

wait that's. probably not true? >_> i would assume feathers n shit give you a LOT of surface area per volume

You're probably right, but looking at this abstract I think they're looking ONLY at the surface., not like each feather counts inside outside and then the actual flesh body of the bird.

Estimation of the surface area of the avian body is valuable for thermoregulation and metabolism studies as well as for assessing exposure to oil and other surface-active organic pollutants from a spill. The use of frozen carcasses for surface area estimations prevents the ability to modify the posture of the bird. The surface area of six live homing pigeons in the fully extended flight position was estimated using a noninvasive method. An equation was derived to estimate the total surface area of a pigeon based on its body weight. A pigeon's surface area in the fully extended flight position is approximately 4 times larger than the surface area of a pigeon in the perching position. The surface area of a bird is dependent on its physical position, and, therefore, the fully extended flight position exhibits the maximum area of a bird and should be considered the true surface area of a bird.

https://bio.biologists.org/content/3/6/486

https://www.sciencemag.org/news/2009/07/bird-big-air-conditioning-bill
I imagine these guys know more, they say that the bill can radiate heat "anywhere from 5% to 100% of the bird's body heat loss," and when flying is 4times more efficient at dispersing heat. Which is also 4 times more efficient than elephants' ears and duck bills. Apparently babbies don't know how to regulate heat because they need to control the blood vessels of the beak. Seems like is a conscious effort to do so, or it's possible the vascularization of the beak doesn't happen until their older (this one seems less likely, because you'd need that vascularization in the first place to make the beak.

The bill of the toucan attains its remarkable size through a steep ontogenetic growth (Fig. 1), leading to a bill surface area 25 to 40 times larger than that predicted from scaling relationships (17). Changes in bill length follow a moderate trajectory during the first 4 to 5 weeks of life, scaling with positive allometry, relative to body mass (bill length = 0.33 body mass0.598). Thereafter, when the juvenile attains nearly 80% of its adult mass, the bill exhibits more rapid allometric growth, with the scaling exponent (b) increasing to 0.845, nearly three times predictions from isometry. This positive allometry in bill growth led us to examine whether juvenile toucans (n = 2, mass = 503 g, bill length = 10.7 cm) with actively growing bills would have the same ability to modify heat exchange as adults (n = 4, mass = 676 T 42 g, bill length = 18.7 T 0.4 cm; table S1).

https://science.sciencemag.org/content/325/5939/468

So apparently their bills are much more than expected in terms of surface area which is why they can be 30-50% of the surface area of the bird itself. Hope that answers your question now.

As for how they measured the surface area? Apparently it was a figure S1 from this science article (www.sciencemag.org/cgi/content/full/325/5939/468/DC1) "It is, therefore, remarkable that the toucan bill, which represents ~30 to 50% of body surface area (table S1)."

EXCEPT I CAN'T FIND THAT ARTICLE. So we'll have to BELIEVE THEM and TRUST WHAT THEY SAY. Can't go looking up the methodology they used at all.

"During this period, the young are not brooded by the adults during the day (5) and shiver at temperatures as high as 26 to 27C (5)"
Poor babbies that can't control their beaks. They literally shiver at 80 degrees. That's crazy.

If someone wants to find that article, I just get hit with a I'm not authorized.


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Wow.

That was impressive.

I legitimately appreciated that write up.

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Choco posted...

wait that's. probably not true? >_> i would assume feathers n shit give you a LOT of surface area per volume

You're probably right, but looking at this abstract I think they're looking ONLY at the surface., not like each feather counts inside outside and then the actual flesh body of the bird.

Estimation of the surface area of the avian body is valuable for thermoregulation and metabolism studies as well as for assessing exposure to oil and other surface-active organic pollutants from a spill. The use of frozen carcasses for surface area estimations prevents the ability to modify the posture of the bird. The surface area of six live homing pigeons in the fully extended flight position was estimated using a noninvasive method. An equation was derived to estimate the total surface area of a pigeon based on its body weight. A pigeon's surface area in the fully extended flight position is approximately 4 times larger than the surface area of a pigeon in the perching position. The surface area of a bird is dependent on its physical position, and, therefore, the fully extended flight position exhibits the maximum area of a bird and should be considered the true surface area of a bird.

https://bio.biologists.org/content/3/6/486

https://www.sciencemag.org/news/2009/07/bird-big-air-conditioning-bill
I imagine these guys know more, they say that the bill can radiate heat "anywhere from 5% to 100% of the bird's body heat loss," and when flying is 4times more efficient at dispersing heat. Which is also 4 times more efficient than elephants' ears and duck bills. Apparently babbies don't know how to regulate heat because they need to control the blood vessels of the beak. Seems like is a conscious effort to do so, or it's possible the vascularization of the beak doesn't happen until their older (this one seems less likely, because you'd need that vascularization in the first place to make the beak.

The bill of the toucan attains its remarkable size through a steep ontogenetic growth (Fig. 1), leading to a bill surface area 25 to 40 times larger than that predicted from scaling relationships (17). Changes in bill length follow a moderate trajectory during the first 4 to 5 weeks of life, scaling with positive allometry, relative to body mass (bill length = 0.33 body mass0.598). Thereafter, when the juvenile attains nearly 80% of its adult mass, the bill exhibits more rapid allometric growth, with the scaling exponent (b) increasing to 0.845, nearly three times predictions from isometry. This positive allometry in bill growth led us to examine whether juvenile toucans (n = 2, mass = 503 g, bill length = 10.7 cm) with actively growing bills would have the same ability to modify heat exchange as adults (n = 4, mass = 676 T 42 g, bill length = 18.7 T 0.4 cm; table S1).

https://science.sciencemag.org/content/325/5939/468

So apparently their bills are much more than expected in terms of surface area which is why they can be 30-50% of the surface area of the bird itself. Hope that answers your question now.

As for how they measured the surface area? Apparently it was a figure S1 from this science article (www.sciencemag.org/cgi/content/full/325/5939/468/DC1) "It is, therefore, remarkable that the toucan bill, which represents ~30 to 50% of body surface area (table S1)."

So...looking at S1, WE GOTTA GO DEEPER.

Predicted Bill Area (cm2)(S7) 7.6 0.6 6.4
Predicted Body Surface Area (cm2) (S7) 622 52 513

How did they predict it? Using an equation FROM ANOTHER FUCKING PAPER. S7. G. E. Walsberg, J. R. King, Journal of Experimental Biology 76, 185 (1978).

https://jeb.biologists.org/content/76/1/185.short
This one is free thankfully.

So this guy's paper is basically saying, don't use surface area of skin to determine heat exchange, use the feather surface area, which makes sense. Now where are the formulas.
"In studies of avian thermal biology, the skin surface area is frequently used in calculations (e.g. Veghte, 1964; Pohl, 1969; Drent & Stonehouse, 1971; Calder, 1974) and is commonly estimated using Meeh's (1879) formula with Rubner's (1883) constant of 10 (1) where Sskin is skin surface area beneath the feathers (cm2) and M is body mass (g)."

Sskin as only that skin surface beneath the feathers (doesn't count feet or beaks)


Note how the tail gets ignored for surface area calculations lol. It makes sense they don't help in thermal significance. So I THINK this explains why the surface area seems REALLY off. The surface area of the tail accounts for a MASSIVE amount of the bird, take that away and I can see now how the surface area of the beak takes up 30-50% of the bird. Now we understand what they mean. The heat exchangeable surface areas of the bird is what they mean when they say the surface area of the bill accounts for 30-50% of the bird. There we go IT HAS BEEN FIGURED OUT. You were right chocolate. It was odd that the surface area of the beak takes up 30-50% of the bird, it is untrue, but they are correct that for the surface area that is used in heat exchange, the beak accounts for 30-50% of that. An hour spent figuring out this nonsense. WITNESS ME https://youtu.be/4KlSuGNt8e4?t=12

An adorable thermal video of a toucan going to sleep and tucking its feathers in.
https://science.sciencemag.org/highwire/filestream/590593/field_highwire_adjunct_files/0/1175553s1.mpg

"During this period, the young are not brooded by the adults during the day (5) and shiver at temperatures as high as 26 to 27C (5)"
Poor babbies that can't control their beaks. They literally shiver at 80 degrees. That's crazy.

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Alteres posted...

Wow.

That was impressive.

I legitimately appreciated that write up.

Haha, you may want to reread it again, I managed to find that missing article in the end. It's in bold. Chocolate was right, but there's a cute thermal vid of a toucan sleeping in there too, that you'll have to download. Made it kind of worth it.

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And I learned a bunch of stuff on my endeavor to figure out what is right and wrong. Baby toucans shiver when it's 80 degrees F. Still blows my mind. These are highly adapted birds to their environment, makes sense considering what they do with their beaks. Apparently they also overheat in flight too if you read more, but I'm burnt out to expound upon that and I don't care now.

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wow damn fuck what

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bump

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