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 that revealed the type of dinosaur that 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
