Piecing together the evidence from his bones and those of other animals found in the Morrison Formation we could reconstruct how Al might have lived and died. The story opens as Big Al hatches from an egg buried in a nest chamber underground. The nest of a dinosaur very like Allosaurus has been found near Lourinha, Portugal. There were about 100 eggs in the nest and there may have been many more. Inside some of the eggs were tiny fossilised embryos which revealed the type of dinosaur which had laid them.
Eggshells have tiny pores to let the embryos inside breathe.
Eggs which are buried underground have bigger pores than those incubated above ground. By examining the pores on the eggs in Portugal we could tell that the nest had originally been underground. Hatching out Allosaurus eggs have been found which would have contained tiny embryos In the programme, Al's mother is nearby and helps dig out the youngsters as they hatch. This is speculation based on the behaviour of other animals which bury their eggs. For these animals, good nesting sites tend to be rather rare.