Charlotte Uhlenbroek enters the busy forest, a place where hundreds of different animals are all competing to communicate. They use astonishing techniques to get their messages across. Charlotte howls to a pack of wolves to see if they will call back and she is amazed when they do. Wolf howls travel over miles and the calls reveal the size and the health of the pack. In the rainforest, Charlotte finds it hard to see any animals in the thick canopy, but the place is alive with their calls. To be sure their voice is heard, many animals have fixed timeslots during the day to call. The quality of the serenade is important too. When she plays back recordings of male green frogs she quickly concludes that female frogs find deeper voices sexier. Even plants join in and call for help. When a caterpillar attacks a cotton tree, the plant releases a volatile chemical that wafts a SOS message through the dense forest. A parasitic wasp picks up the alarm and goes into action, attacking the invader. On the forest floor, a male wolf spider has to find a mate, but if she does not like him, she will eat him. The male performs a tap dance in a desperate bid to impress her. Charlotte enters a virtual world inhabited by cyber-spiders to prove that females prefer males with the hairiest legs and the fanciest footwork. In Australia, a male satin bower bird goes to great lengths to woo a female. Charlotte tests how good he is at reading a female's body language using a robotic female bower bird. A quick tilt of the head, a flick of the wings and a crouched body and he is besotted with the robot. Show less