Lizards' and Breathing/Oxygen?

[Ogrork the Mighty]

For all those reptilian experts out there, here's a question for you. Do lizards need more or less oxygen than humans do? For example, at high altitudes? Of course, lizards are smaller and would need less overall but I'm thinking on a pound-for-pound basis. Is the reduced oxygen supply at high altitude to blame for lack of lizards at such heights, or is it more of a cold thing?

 

[Alchemist]

I'm no expert, but I do know that generally speaking, reptiles operate at much lower metabolic rates than mammals. That means that they would consume less oxygen than a comparably sized mammal.

Since they don't generate their own heat, they are less tolerant of low temperature. I think that's why you see mammals in cold regions (high metabolism=self heating) but not so much lizards and the like.

 

[ErickArnell]

Cold blooded -> Less oxygen

Lizards are cold blooded. Biggest difference in this context with mammals (like me and, I assume, you) is that their metabolisms are a lot slower. Less metabolic activity, less need for oxygen to "stoke the fire."

We get lizards and snakes at 5000 ft altitude in the Rocky Mountains at least. I only know because I need to watch out for rattlesnakes when out hiking.

 

[Shemeska]

Off the top of my head I recall that some form of alligators or crocs used a varient form of hemoglobin that was copper based rather than heme based and which bound oxygen more efficiently, allowing them to hold their breath underwater for longer. Not my area of biology though so best to look it up rather than take me as gospel here.

 

[Ogrork the Mighty]

Cool, so it wouldn't be totally offside to have lizardmen operating more comfortably at higher altitudes than humans?

 

[Gez]

No, it wouldn't be totally offside. Especially in a fantasy world with big 6-limbed reptiles who breathe fire.

 

[Ogrork the Mighty]

Yeah, but even red dragons don't tend to live in cold climates...

 

[kirinke]

high altitudes: cold-drakes, white dragons and silver dragons respectively.

 

[Nifft]

IMC, Fire Dragons live wherever they darn well please.

-- N

 

[Umbran]

Off the top of my head I recall that some form of alligators or crocs used a varient form of hemoglobin that was copper based rather than heme based and which bound oxygen more efficiently...

Nope. All known terrestial vertebrates use an iron-carrying hemoglobin for oxygen transport through the blood.

Most molluscs, and some (but not all) arthropods use hemocyanin instead, and that uses copper as the carrier.