Headscratchers / The Ballad of Big Al

• One aspect of the special that has caused some confusion is the depiction of Allosaurus nesting habits. There seems to be plenty of fossil evidence that suggests the youngsters stayed in their nest until they were strong enough to find food for themselves, up to which point the mother brought them food. I have also heard that they may have nested in groups, but I haven't found any solid info about this on the net yet. However this had all supposedly been known before the special was made. So what gives? Does the way the episode shows allosaurs nesting have any evidence to back it up?
  • I do not know of any evidence that supports any of those claims. They sound like speculation to me. Indeed, known hatchlings of non-avian theropods (troodonts and oviraptorosaurs) show that they were precocial, not nest bound. Caveat: I'm not familiar with carnosaurs, and there could potentially be evidence that I'm not aware of.
    • Original Headscratcher-er here: A quick Googling session (including clicking through the "Look Inside" feature of a couple of dino books) resulted in the following revelations: allosaur nests have been found to contain a huge number of teeth, from adults and juveniles alike, as well as fragmentary remains of sauropods, occasionally with tiny allosaur teeth still being stuck into them. Bob Bakker, who found the site, claims that this is evidence that parents brought food for their chicks for at least a short while, and there even was a TV documentary about the uncovering of the nesting site, but it's so old, it apparently sank into oblivion. What's interesting is that the second part of the Big Al special also discusses allosaur nests, but it doesn't mention group-nesting, and the babies are shown leaving the nest right after they hatch.
    • Nowadays, most dinosaur experts agree that dinosaurs were like modern crocodyllians and palaeognath birds, being precocial or superprecocial. The idea that allosaurs brought food to their young is not implausible per se - crocodiles do that sometimes - but it is more likely that the so-called group nest was a collection of scavengers, a la Komodo dragon or vulture groups. It doesnt help that the group of people that defend intense parental care in Allosaurus generally know jack shit about Mesozoic birds.
    • More on Bakker's "lair sites;" what was significant about them is that all the shed teeth were from Allosaurus while the Morrison has several large predators (Ceratosaurus, Torvosaurus, crocodiles). The sites fell into two groups in his study; those with a mix of teeth from several different predators and those with just Allosaurus teeth. Using Komodo dragons for comparison doesn't quite work, as there are no other large predators native to the Komodo dragon's range that could give a "non-nest site" signal.

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