no most did go extinct except there ansestors birds By scientific comparisons of extinct fossil remains of theropod dinosaurs (carnivorous dinosaurs) and modern avian (birds), scientist find very close similarities for modern birds to prehistoric theropods the half bird half dinosaur archaeopteryx. but The extinction of most of the dinosaurs remained a mystery. Some animals in cryptozoology are thought to possibly be surviving Dinosarus, such as Mokele-mbembe. The existence of these animals is unproven and in most cases highly to extremely improbable.