Aubrey discovers the amazing lengths animals go to to make themselves heard.

This week, Aubrey goes on a sound safari where being the loudest really matters. The Costa Rican jungle, one of the noisiest spots on the planet, plays host to an astounding array of animals. In this incredibly frenetic, noisy environment, Aubrey explores the challenges animals face in communicating with each other, when they can so easily be drowned out.

Aubrey and his two guides go on the trail of frogs, crickets and cicadas to find out the strategies and extraordinary lengths they go to, and the central role sound plays in their survival.

Lori Wollerman, of America's Hood College, has been studying Costa Rican frog sounds for years, but the trip proves to be the first time that Henry Bennett-Clark of Oxford University, one of the world’s leading experts on crickets and cicadas, has ventured into the jungle of Costa Rica. The trip throws up lots of surprises, not least the amazing variety of frogs and the breadth of their vocal ranges.

Later in the series, Aubrey finds out about the remarkable latest research into communications networks by finding out about how animals and birds ‘eavesdrop’ on other species. He goes on an underwater sound safari, discovers sounds human ears are not normally privy to, and samples some of the acoustic hotspots from around the world.