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.
Fortey travels to the rainforests of Madagascar - an ancient island that has spawned some of the most extraordinary groups of plants and animals anywhere in the world. From beautiful Indri lemurs, toxic frogs, and the cat-like giant mongoose called the fossa, to evolutionary oddities like the giraffe-necked weevil and the otherworldly aye-aye, he uncovers the secrets of the evolutionary niche - examining how, given millions of years, animals and plants can adapt to fill almost any opportunity they find.
A humpback whale mother and calf embark on an epic journey from tropical coral paradises to storm ravaged polar seas. Newly discovered coral reefs in Indonesia reveal head-butting pygmy seahorses, flashing 'electric' clams and bands of sea kraits, 30-strong, which hunt in packs. Elsewhere plagues of sea urchins fell forests of giant kelp. Huge bull fur seals attack king penguins, who despite their weight disadvantage, put up a spirited defence.