Planet Earth was inhabited by many wondrous creatures throughout the Permian period. Massive geologic changes finally allowed life to thrive on land and sea, producing voracious saber-toothed carnivores like Gorgonopsid and the terrifying 40-foot shark Helicoprion. But it couldn't last forever...
As temperatures hit minus 60 food becomes scarce, and animals such as foxes and hares shed their colourful coats to camouflage themselves in the snow. The end of winter heralds one of the world's greatest feeding frenzies as large ocean predators target the millions of fish who have found refuge in the Gulf of Alaska.
A look at wildlife in hostile environments, including glow-worms, condors, thorny devils, emperor penguins and polar bears. High in the mountains, deep underground, out in the deserts and at each of our vast frozen poles, animals have had to develop extraordinary resilience to survive. There are many challenges faced by animals living in extreme environments. Superbly adapted to these inhospitable habitats, their fortitude and resilience.
It may take two to make a baby - but not necessarily two to bring it up. So what makes a parent decide to stay or go? Especially if that parent is a dad. From the California mouse mother who has to kickstart her partner's paternal instincts, to Adelie penguin parents who can't leave their eggs alone for five minutes; from cheetah mums practicing promiscuity to keep the dads on side, to flamingo parents both producing milk for their young. We see just how far these incredible parents go in order to protect and nurture as many offspring as possible through to adulthood.