Dinosaurs took months to hatch out of their eggs. That may have doomed them.

Jan 8, 2017

By Sarah Kaplan

For dinosaurs, hatching eggs was a long-term commitment.

A nest pinned the parents down to the spot where the eggs were laid. As long as they were incubating their eggs, they couldn’t venture off in search of food or to flee predators. And their eggs incubated for a very long time.

That’s according to Gregory Erickson, a paleobiologist at Florida State University and the lead author of a new study on dinosaur hatching times in the journal Proceedings of the National Academy of Sciences. Close examination of embryos found fossilized inside their eggs suggests that dinosaurs took as many as six months to hatch — far longer than their closest modern descendants, today’s birds.


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3 comments on “Dinosaurs took months to hatch out of their eggs. That may have doomed them.

  • Successful creatures were small and adaptable animals that lived fast and died young. For the ancestors of birds, quick incubation times may have boosted their ability to repopulate and evolve to fill ecological niches left vacant after the disaster.

    Erickson gets closer to the more parsimonious explanation. Dinosaurs that survived immediate incineration and cascading death from fatal injuries after the asteroid explosion simply starved to death as most of the earth’s vegetation, unable to flourish with photosynthesis, died off in a nuclear winter of darkness. Most species were large creatures, and many were gigantic requiring tons of vegetable matter (trees, plants and grass) every day. The warmer more humid climate of the cretaceous supplied the requisite plant food. The carnivorous dinosaurs depended on their herbivorous counterparts and both obviously depended on huge supplies of fodder that grew “the meat” of the former. The small, light avian dinosaurs evolved into birds, could fly above the wasteland ranging far and wide searching for scarce food sources and nesting places. The same held true for small land mammals that could scurry into burrows and survive on scraps and marine species that could find shelter in the depths of oceans.

    FROM ARTICLE: **But dinosaurs were large and probably endothermic (warm blooded), which made them “profligate wasters of energy,” Erickson said. They also took a long time to reach sexual maturity. **On top of all this, a slow incubation might have been a “black ace” — contributing to long generational times that made it harder for dinosaurs to bounce back.****

    Slow incubation of eggs and longer generational length would not present the formidable challenges that Erickson proposes compared to the intractable conditions for relatively rapid starvation. World dinosaur population at its peak was prolific and included (perhaps) 1,000 species with up to 60 million living individuals. Erickson does not take into account age structure within populations. While it may have taken 3 to 6 months incubation to produce an offspring, not all dinosaurs lived on a simultaneous timetable of development. When the asteroid hit, millions occupied young cohorts from infancy to fertile maturity while millions more in gestation were days or weeks from hatching. Over several years the high-output vegetation ecosystem the dinosaurs depended on for food would have shriveled into a death spiral even though large though shrinking fertile cohorts may have survived for decades, centuries, millennia. These huge ravenous creatures more than likely just starved into extinction.



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  • @WP – link – While the dinosaurs did whatever it is dinosaurs do while nesting (scientists think some species sat on their nests like birds, while others probably buried their eggs like reptiles), the embryos inside slowly develop. Just before the halfway point of their incubation period, they start to grow teeth.

    It seems unlikely that they would sit on eggs for months.
    More likely tose with long incubation periods, would let a warm climate or heat generated by rotting vegetation incubate them, – as crocodiles do – in which case, a serious drop in global temperature or lack of accumulating vegetation would inhibit facilities for hatching!



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  • Another interesting discovery is the discovery some ancient dinosaur protein.

    http://www.bbc.co.uk/news/science-environment-38810065

    Ancient proteins dating back 195 million years have been found inside a dinosaur bone.

    The discovery pushes back the oldest evidence for preserved proteins by 100 million years.

    Scientists have also found traces of a mineral that probably came from the blood of the early Jurassic dinosaur.

    Soft tissues provide new insights into the biology of dinosaurs and how they evolved.

    They are rarely preserved during the process of fossilisation, during which bones and teeth are slowly transformed into “rock”.

    Robert Reisz, a palaeontologist from the University of Toronto Mississauga, in Canada, said: “We hope to be able to learn more about the biology of these animals and the more we know about their soft tissues the more we will know about them overall.

    “We are actually looking at the preservation of the original materials that were in the living organism rather than an impression of the soft tissues that were there.”

    The researchers studied the fossils of a Lufengosaurus dinosaur using infrared spectroscopy with a synchrotron in Taiwan.

    Preserved fragments of collagen and iron-rich proteins were found within the walls of blood vessels running through rib bones.

    They think the remains of dinosaur blood may have preserved the collagen for almost 200 million years.

    Lufengosaurus belongs to a group of dinosaurs which lived during the Early Jurassic Period in what is now south-western China.

    A site in south west China has produced dozens of skeletons of the plant-eating dinosaur.

    The discovery follows research by the same team on the oldest dinosaur embryos ever found.

    Insight into life in a dinosaur egg

    The research is published in the journal, Nature Communications.



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