4 ms·
He’s leaving out the bit about the low oxygen tension and what adaptations allow birds to effectively deliver oxygen at altitude. The air sac system is good fo
by projektfu 6y ago
He’s leaving out the bit about the low oxygen tension and what adaptations allow birds to effectively deliver oxygen at altitude. The air sac system is good for high-demand situations, where increased ventilation is needed. But if the blood is simply not able to pick up enough oxygen, the ventilation rate doesn’t matter much. This is why we need pressure suits at high altitude.
I’m sure when dinosaurs were dealing with 12% oxygen they had developed adaptations to handle it. Special hemoglobins, etc. Whatever that is, is the real reason. The efficient air sac-lung system is better at explaining how they ventilate well and deal with high winds.
- nradov 6y agoDid dinosaurs really deal with 12% oxygen? I thought that atmospheric oxygen content was already somewhat higher by the time the first dinosaurs evolved.
- mkl 6y agoNo they didn't. The story seems rather light on accuracy. See here: https://en.wikipedia.org/wiki/Geological_history_of_oxygen https://en.wikipedia.org/wiki/Geological_history_of_oxygen and https://en.wikipedia.org/wiki/Paleoclimatology https://en.wikipedia.org/wiki/Paleoclimatology
- samstave 6y agoThis is the reason why hummingbirds are the most amazing creatures and their blood should be studied, more deeply. They basically have the ability to pull in oxygen at an order of magnitude greater ppm than hemoglobin based mammals... But their metabolism requires a really high sugar intake constantly. But their speed and endurance is stunning, some humming birds migrate btwn north and south america.... They are also fiercely territorial - ive witnessed two fight literally two feet from me - attacking and pecking at eachother, with the loser of the battle falling on the ground... (whom i picked up and brought him to bart in an uber i was catching - he woke up and escaped my grip and i was in an uber with a hummingbird flying around... ill never forget that experience, the driver loved it)
- js2 6y agoWe have a hummingbird feeder outside our kitchen window. Watching their antics all summer long is a great source of entertainment. The feeder has six feeding spots, but of course they chase each other off so that only one can feed at a time. Sometimes a wasp is at the feeder and the wasp and hummingbird tolerate each other.
- samstave 6y agoWatch this https://www.pbs.org/wnet/nature/super-hummingbirds-full-episode/14586/ https://www.pbs.org/wnet/nature/super-hummingbirds-full-epis... “Humming birds have the highest metabolic rates of any invertebrates”
- Someone 6y ago“We're sorry, but this video is not available” Checked the transcript. Luckily, it says vertebrates :-)
- js2 6y agoProbably only available in the U.S. and maybe only if you support your local PBS station. It’s also available for purchase on DVD or iTunes. https://shop.pbs.org/nature-super-hummingbirds-dvd/product/NAT63401 https://shop.pbs.org/nature-super-hummingbirds-dvd/product/N...
- deleted 6y ago[deleted]
- bch 6y ago*vertibrates
- deleted 6y ago[deleted]
- deleted 6y ago[deleted]
- layoutIfNeeded 6y ago>I’m sure when dinosaurs were dealing with 12% oxygen they had developed adaptations to handle it. Dinosaurs never had to deal with 12% oxygen. Also, mammals' ancestors roamed the Earth together with dinosaurs, so they would have developed a similar adaptation if your hypothesis was true.
- projektfu 6y agoWell, I’m just going by the “facts” as they are in the story.