A new study finds that dinosaur eggs took between 3 and 6 months to hatch—twice as long as predicted from bird eggs of similar size. Trex eggs or nests have never been found, but fossils of other Tyrannosaur relatives suggest that they laid elongated eggs, roughly 20 or more at a time. T. Rexes Were Loving Parents It's possible that T. rex parents were protective of their young as well. There is a surprising lack of juveniles in the fossil record. This could mean a number of things, and one of the theories is that most young T. rexes lived long enough to reach adulthood, which would have meant parental help and guidance.