Nigel goes through the time portal to South America 1 million years ago when the sabre-tooth species known as Smilodon were in their prime (having recently entered South America after the Panama land bridge formed), but the terror birds (Phorusrhachids) were dying out; before that South America had been cut off from the other continents for 30 million years. He drives through a moving herd of Toxodon; he follows them to find where they were going, and he sees that they were going to water to swim or wallow in: he sees that they lived like modern hippopotami, and thus may be dangerous like hippos. A huge male Toxodon chases Nigel's jeep, and he has to drive fast and far before it gives up the chase. In the park the female Ornithomimus had laid more eggs. Two of them have rolled out of the nest and she leaves them there, so Susanne must rescue them for artificial incubation, as all those eggs are precious. Susanne stalks up to them and picks up them; the Ornithomimus does not chase, but demonstrates, causing a flurry among some white egrets. Bob puts the 2 eggs in an incubator at 33 °C, as this is best temperature for crocodile and ostrich eggs. On site Nigel sees a female Smilodon stalk a Toxodon and then after a short chase, jump on its head and bite its throat to kill it. More Smilodon come, including some 6 to 8 week old cubs. While waiting Nigel has a coffee and the Smilodon eat their fill and go away. A Phorusrhacos starts to eat from the carcass. Another Smilodon appears and chases it away, forcing it to drop a lump of meat which it had pulled off. That sort of pressure is why the Phorusrhacos were dying out. Nigel stalks up to that dropped piece of meat and picks it up. The Smilodon on the kill demonstrates at him but does not charge at him. Nigel tows the piece of meat behind his jeep and entices the Phorusrhacos to chase it through the time portal into the park. In the park the eggs incubated by the Ornithomimus hatch and the resulting young run about (the first baby dinosaurs for 65 million years), but the two eggs in the incubator do not hatch. The young Ornithomimus are covered in downy feathers. Accompanied by big cat expert Saba Douglas-Hamilton, Nigel goes through the time portal to South America in 10,000BC when the sabertooth species were dying out. They find a drier climate and no big game. Nigel and Saba separate, on foot. Saba hears animals' alarm cries, but Nigel finds nothing. Saba finds a deposit of fresh Smilodon faeces. She pulls it apart with a knife and fork and finds that it is full of hair and bone and bits of animal hide, as if hunger had forced the Smilodon to scavenge old remains of carcasses. Nigel hears vegetation noise from an animal near him. He finds, catches and releases an ordinary modern-type armadillo and remarks that a million years earlier there were giant armadillos about. Saba later finds something in the grass; sadly, it is a dead Smilodon cub. Nigel cannot find any signs of ill health and realises that the cub must have died from starvation. Saba watches the female Smilodon hunting. It sees her and confronts her. She backs off. Nigel meets Saba. Due to lack of prey the female Smilodon is hunting unsuitably light fast prey, a deer: when she charges, the deer runs away easily. Later they see her suckling a live cub, but she is making little or no milk for it. A male Smilodon turns up: there is risk that it will kill the cub to bring its mother into oestrus sooner. In the jeep they anaesthetic-dart the male Smilodon and start to wait 10 minutes while the dart drug works. The Smilodon charges out of bushes and jumps on the front of the jeep; they back off. In the park the men have finished building a partition across the Tyrannosaurus enclosure, and put a Tyrannosaurus on each side. Matilda keeps threatening Terence but now cannot reach him. On site, they find the male Smilodon and load it up on the back of the jeep. Then they go for the female, planning to anaesthetic-dart her and load her and her cub. When they reach her, the cub has starved to death. The female Smilodon is badly underweight from trying to lactate on too little food, and is dying as well, so Saba anaesthetic darts the female Smilodon. A little while later, Nigel and Saba load the female into the jeep, but both are upset that the cub could not be saved. The two Ornithomimus eggs in the incubator hatch, late but successfully: Bob guesses that the incubator's temperature had been set a little too low. The two resulting hatchlings see Bob and imprint on him, thinking that he is their mother and follow him about. They eat food pellets out of his hand. With good food and no need to lactate, the two Smilodon and the Phorusrhacos recover from their hunger over the next fortnight. However, tensions remain high, as Matilda's increasingly aggressive behaviour could spell danger for the Park. British Broadcasting Corporation, BBC©

• published: 14 Apr 2009
• views: 11667