"Dinosaurs were basically caught holding bad cards—a dead man's hand"
October 8, 2019 8:05 AM   Subscribe

What do you know about dinosaur eggs? What do you want to know? PopSci: egg fossils can reveal a lot about how dinosaurs lived, including the understanding that dinosaur eggs took between 3 and 6 months to hatch (Science Mag), which put them at a disadvantage against other reptiles, birds and mammals. Want to know more? The Embryo Project Encyclopedia has a page on Dinosaur Egg Parataxonomy, and the UC Museum of Paleontology has a section on fossil eggshells.

How big can eggs be? (Earth science Picture Of the Day) compares a large ostrich egg, a midsize chicken's egg, and a tiny hummingbird egg, and claims that dinosaur eggs never got as big as ostrich eggs, but the San Diego Zoo notes that ostrich eggs averaging 6 inches (15 centimeters) in length, 5 inches (13 centimeters) across, while the largest-known type of dinosaur eggs reach up to 23 inches (60 cm) in length (Vision Times). American Museum of Natural History has an article that notes:
Also, there is a limit to the size any egg can be. Eggshell is very brittle, so the larger the egg, the thicker its shell must be to keep from shattering. However, the shell must also allow oxygen and water to get through to the embryo growing inside, and, above a certain size, the egg wouldn’t be both suitably strong and porous. So although the sauropod young grew big very fast, they started out relatively tiny.
Speaking of oxygen, dinosaurs' superior lungs may have allowed them to outcompete early mammals, according to a new study of modern-day alligators (National Geographic, 2010).
Scientists found that a method of high-efficiency breathing used by birds is also employed by today's alligators, which share a common ancestor with dinosaurs.

In mammals, each fresh breath carries oxygen-rich air to "cul-de-sacs" in the lungs called alveoli.

Air circulating through these sacs transfers oxygen into the bloodstream that picks up the blood's carbon dioxide waste.

But birds don't have alveoli. Instead, the air flows in one direction into the birds' air sacs.

This adaptation keeps birds' lungs filled with "fresh" air, allowing them to breathe at altitudes that would kill other animals.
Bird-like lungs might have also helped giant sauropods keep cool, despite being warm-blooded giants. (For example, here are some equations testing theoretical limits of animal scales, with hummingbirds and elephants as modern examples.)

Dinosaur egg news, previously.
posted by filthy light thief (4 comments total) 15 users marked this as a favorite
There would have to be a lot of superior nutrition in an egg to feed an embryo for 3 - 6 months.
posted by theora55 at 12:01 PM on October 8, 2019

Hmm, I wish that the scientific article linked to in the previously actually came with a time estimate, since it states its results "possibly indicat[e] that short incubation times were characteristic of sauropodomorphs" -- the opposite of this new study (though whatever "short" means I couldn't discern).

Paging a palenotologist?
posted by puffyn at 12:24 PM on October 8, 2019

There would have to be a lot of superior nutrition in an egg to feed an embryo for 3 - 6 months.
posted by theora55 at 4:01 AM on October 9 [+] [!]

You just know, once we get lab-grown meat down, that this is what the super-rich will use it for. Synthetic dino egg omelettes will be the wagyu steak of the future, which means actual cloned velociraptor will be our grandchildrens' panda meat.

By then, they'll have forgotten Jurassic Park.
posted by saysthis at 9:07 AM on October 9, 2019

Those who forget Jurassic Park are doomed to repeat it.
posted by Pickman's Next Top Model at 8:54 AM on October 10, 2019

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