There's considerable evidence that dinosaurs once lived at polar latitudes. How did they survive the cold?
The Making of the Big Al special
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
75 million years ago the Mongolian desert was home to dinosaurs of all shapes and sizes - including one with the largest claw of all time.
Argentinosaurus was the largest dinosaur ever - 35 metres long, and up to a hundred tonnes in weight.
When dinosaurs first appeared the world was very different. There were no mammals, no birds and no lizards. But there were some lizard-like reptiles.
Why the dinosaurs died out is one of the most frequently asked questions of dinosaur experts. Will we ever know the answer?
There's considerable evidence that dinosaurs once lived at polar latitudes. How did they survive the cold?
The largest animals ever to fly were pterosaurs. But during their reign, birds as we know them were also beginning to appear.
While dinosaurs dominated the land, huge marine reptiles ruled the water. Ichthyosaurs looked very like dolphins - but they weren't the top predators of the Jurassic seas.
In the Early Jurassic, dinosaurs started getting larger. Diplodocus was over 30 metres long - but even he wasn't safe from predators
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Walking With Cavemen - 03 - Savage Family
The Africa of two million years ago is a crossroads in human evolution. Half a dozen or more different species of ape-men exist alongside one another. Each of them has exploited the environment in a different way and has developed their own survival strategy . One and a half million years ago, a new breed of ape-man walks the land. In southern Africa, Homo ergaster has taken the next step to becoming human. They have long, modern looking noses, which cool air as they breathe.
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Walking With Cavemen - 02 - Blood Brothers
The Africa of two million years ago is a crossroads in human evolution. Half a dozen or more different species of ape-men exist alongside one another. Each of them has exploited the environment in a different way and has developed their own strategy for survival.
It's 3.5 million years ago and in East Africa a remarkable species of ape roams the land. Australopithecus afarensis has taken the first tentative steps towards humanity by standing and walking on two legs. Just a few million years previously, Africa was covered, almost edge-to-edge, with dense rain forest. Our ancestors almost certainly used all four limbs to move and live and hunt in their tree-top homes. But massive geological turmoil changed their destiny
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