Voir Massive Nature, Series 1 - Episode 3

Every year, countless millions of sardines head north up the coast of South Africa. In their wake follows an armada of the oceans greatest predators: sharks, dolphins, whales and birds. They all began on their collision course months before – but somehow they always rendezvous at the same place and the same time and the outcome is considered to be one of the most spectacular wildlife events anywhere on Earth. With the aid of state-of-the-art graphic software, we deconstruct the action to find out what it is that sends these sardines on an apparently suicidal journey and how all these predators collaborate to kill millions of sardine in a frenzied bait ball. Also: every year, 40 million Brazilian free-tailed bats stream out of their summer homes, the 'guano caves' near San Antonio in Texas. It is the biggest congregation of mammals on the planet. Half are babies precariously taking wing on their maiden flight, running a deadly gauntlet of hawks, falcons, snakes and racoons, who have been eagerly awaiting their debut. How do all these predators know just the right time to arrive, and the best place to be for easy pickings – and how did all these creatures come to meet on this one fateful day? And what can the bats do to stay alive? This massive flock is a blessing and a curse – it gives them safety in numbers, but many will be lost through mid-air collisions. Those that can, use the flock dynamics to their advantage. How does an individual navigate in the vast pulsating flock, and find its way out to safety?