Dinosaurs have undergone any number of scientific makeovers in the last few decades. When I was young, they were depicted as lumbering, over-sized lizards, “cold-blooded” and drab. That simplistic image was eventually replaced with a more vibrant one. The velociraptor à la Jurassic Park was agile, quick, birdlike — and quite possibly festooned in feathers. Bright colors (though maybe not Barney purple) and rich social lives have also been proposed.
Scientists’ latest look at dinosaurs offers up another revision. As Meghan Rosen describes in “Dinosaurs had middling metabolisms,” the new work compares dinosaur growth rates, estimated from fossils, with growth rates from modern animals for insights into dino metabolism. Energetically, dinosaurs were neither fowl nor lizard, but something in between, the researchers conclude. Like today’s sea-faring tuna and great white sharks, dinos share some traits with both ectotherms (what people mean when they say “cold-blooded”) and endotherms (“warm-blooded”).