- Jul 2017
- Crows nest
I think it's really difficult to say just how many eggs T.rex laid, but I would think due to the upper size limit on eggs, then many, and for the reasons you describe of hoping that enough survive to ensure species survival. It's still a little difficult to get a grip on this egg thing with dinosaurs, though of course they were very successful. A diminutive Kiwi laying one eye-wateringly huge egg, but an 80 ton Argentinasaurus laying eggs of about the same size, though without the eye-watering aspect. But it's the egg size limitation thing of course. We really, really do need to find a fossilized T. rex nest with embryos just about to hatch to see if they were altricial or precocial, for until we know that basic fact, then everything else is speculation and personal opinion. And mine, as I think I have already mentioned, is that they were altricial and needed care. This is often the case with predators, and I think we should compare T. rex to the majority of birds and even mammals, not crocodiles where they feed themselves even if the parent does give some protection. While at least the big sauropods could not possibly care for their young, which were hatched as precocial anyway, we see that hadrosaurs did care for their altricial young, and with a size differential between adult and young roughly the same as T. rex....and yet, another speculation:
Some raptors drop entire kills in their nests and share them with the young. A big T.rex kill could feed a T.rex for multiple days, plus a large amount of progeny (presuming parental care, of course). Not many T.rex's, right? Species with low success rate of young growing to adulthood tend to have large broods ... and in spite of that, typically only replace themselves in their lifetime. Think of frogs laying 100's of eggs over their lifetime, and only JUST replacing the adults when it's all said and done. So, there COULD have been lots of little T.rex tykes, sharing a kill, only to be snapped up by anything big enough to swallow them.
Though when we say adult, the reality will be that juveniles were of breeding age long before they reached full size. So probably most T. rex parents would have an easier time giving parental care as there was not such a vast gap in size. It's easier to see thirteen year old "Jane" feeding young than huge 28 year old "Sue". Of course a fully grown T.rex can reach it's snout down to ground level, but I really do find it difficult to visualize it actually feeding hatchlings. Then what food would they drop? could even a thirteen year old, and maybe younger, parent tear meat off prey in small enough portions. Did they regurgitate partially digested food, like penguins, and the same can be asked of hadrosaurs, did the parent feed the young with already chewed vegetation, I think probably.
So, as some completely unfounded speculation, what if juvenile T.rex, younger than breeding age and still comparatively small, acted as nest helpers, as some corvids, and fed the new generation. I have even seen eaglet siblings feeding each other, a change from trying to kill each other I guess, and I would presume that T.rex facial biting and kicking began in the nest. Btw, a study shows that some of the facial biting was not actually biting, but kicking, as the marks, and in some cases holes, do not match teeth but do match pedal claws. Lack of substantial arms makes T.rex much more birdlike, and birds kick, and not just flightless birds, eagles kick each other. Clearly just seeing a live T.rex would be mind blowing, but to see them kickboxing as well....