Do all dinosaurs lay eggs or do some give live birth?
There’s no evidence of any live birthing among dinos. A previous respondant wrote: “Plus live birth is only seen in mammals, yet not even all mammals do.” That’s actually wrong for quite interesting reasons. At least, it is if you’ll accept ovoviviparity as being live birth. This is when animals retain eggs within the body, and let them hatch out there rather than in the outside world. There are critters that do that from all kinds of animal groups; some scorpions, sharks, fish, amphibians and reptiles. Some sharks have even gone as far as developing a simple placental system for assisting the development of the growing embryo. Among reptiles, there are a couple of critters which either lay eggs or bear live young according to the circumstances; Bougainville’s skink is one such. There is strong evidence showing that those fish-shaped reptiles, ichthyosaurs, were reproducing with some form of live birth. Lower Jurassic fossils from Holzmaden (Germany) and Lyme Regis (England) include so
