Why Were There No Tiny Non-Avian Dinosaurs? Mammals May Have Been to Blame
Researchers say competition with early small mammals likely kept non-avian dinosaurs from evolving mouse-sized bodies, while birds later escaped that limit through flight.
- Researchers, including Dr. Roger Benson from the American Museum of Natural History and Dr. Stephanie Lechki from Princeton University, published a study August 5 in Evolution suggesting early mammals likely prevented dinosaurs from evolving into tiny creatures.
- While dinosaurs evolved into some of the largest land animals ever, they seemingly could not occupy small size classes that modern vertebrates readily inhabit. The smallest known non-avian dinosaurs weighed approximately 450 grams, more than 200 times heavier than the smallest mammals and birds.
- Mathematical models testing 515 non-avian dinosaur species failed to explain their oversized minimum body mass through physiology alone. Researchers argue that competition with shrew-sized early mammals for ecological niches likely prevented dinosaurs from evolving smaller body sizes.
- Birds, which evolved from dinosaurs, eventually escaped these ecological constraints after developing powered flight. This capability allowed early birds to access new habitats, enabling them to evolve body sizes much smaller than any other dinosaur group achieved.
- "If we want to understand how today's biodiversity evolved, we need to understand why tiny dinosaurs appear to have been missing," Benson said. Understanding these evolutionary forces remains essential to comprehending dinosaur biology and vertebrate evolution broadly.
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Why Were There No Tiny Non-Avian Dinosaurs? Mammals May Have Been to Blame
Dinosaurs evolved into some of the largest animals ever to walk the Earth, but a new mathematical model suggests that early mammals may have crowded them out of the ecological niches reserved for the smallest creatures. The post Why Were There No Tiny Non-Avian Dinosaurs? Mammals May Have Been to Blame appeared first on Sci.News: Breaking Science News.
Science Daily
ecotopical.comDinosaurs became giants — so why did they never become tiny?
Dinosaurs conquered the land at enormous sizes, but strangely, they almost never evolved into truly tiny animals. New research suggests that physiology alone can’t explain this missing miniature end of the dinosaur spectrum—and that early mammals may have been partly responsible. While dinosaurs kept mammals from becoming large, small mammals may have returned the favor by occupying ecological niches that could otherwise have supported mouse-siz…
Why were there no teeny-tiny dinosaurs like we have with mammals and birds?
Everyone knows dinosaurs got really big. Some of the long-necked plant-eaters were the largest land animals ever on Earth, as shown by Argentinosaurus, perhaps 65 to 80 tonnes (70 to 90 tons) and upwards of 30 metres (around 100 feet) long. But why were there never tiny dinosaurs, like the size of a mouse? As far as we know, none ever existed. New research investigates this phenomenon. Scientists employed mathematical models to explore the evol…
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