This debate has gone for centuries since they discovered the first dinosaurs back in the 17th century. Some scientists today believe dinosaurs were warm-blooded in order to place them closer to birds on their evolutionary timescale. Dr. Tom Holtz said,”Birds are dinosaurs! and because birds live today, dinosaurs never did become extinct.” (T.R.Holtz Jr., 2007, “Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages”, New York Random House, p.163)
Does science back this claim up? Is there evidence that dinosaurs were warm-blooded and are ancestors of birds living today? Lets weigh the evidence! We know today that birds are endothermic (warm-blooded). Endothermic means simply that an animal can generate its own internal body heat using its metabolism, independent of its surroundings. While on the other hand, ectothermic (cold-blooded) means that an animal needs external source of heat, like sunlight, to warm its body, like snakes and lizards do. Unfortunately, most fossilized dinosaur bones do not give us this evidence that they were endothermic or ectothermic. This type of study requires soft tissue anatomy. Scientists have found some evidence to support cold-bloodedness in dinosaurs, just opposite of what dino-to bird proponents hoped.
Scientists did a study of the abdominal cavity of the meat-eating (carnivore) dinosaur Scipionyx. It was a small dinosaur some paleontologists claim to be the precursor of today’s birds. In this study they revealed the presence of a lung ventilation system similar to that of modern crocodiles. (J.A. Ruben, “Pulmonary and Metabolic Physiology of Therapod Dinosaurs”, Science, p. 514-516)
An interesting study was a done on the nasal passages of some dinosaur skulls. About ninety-nine percent of all warm-blooded animals have turbinates, coils of membrane-covered cartilage or bone in their nasal passages that reduce water and heat loss during breathing. Dr. John Ruben performed CT scans on four different dinosaur skulls, including two predatory dinosaurs. All scans revealed narrow nasal cavities similar to those of a modern crocodile rather than those of birds. (J.A. Ruben, “the Metabolic status of some Late Cretaceous Dinosaurs”, Science. pp. 1204-1207)
Something more interesting is that fossils of birds (ducks, geese, parrots, albatross, loons, flamingos, etc.) have been found in the same rock layers alongside dinosaur bones. This kind of scratches the idea that birds evolved from dinosaurs. Dr. Carl Werner did research on living fossils and found modern birds in the fossil record.
In conclusion, there is no compelling scientific reason to claim dinosaurs were warm-blooded animals. The evidence instead backs the case that dinosaurs were created as cold-blooded reptiles, and their cold-blooded nature may have played a big part in their post-flood extinction. But no matter if dinosaurs were warm or cold-blooded, it does matter that we believe they did exist and played a purpose in God’s creation.