David tennant narrates this popular bbc natural history series'. '.strtoupper('b')bc documentary series in which animatronic spy cameras, disguised as wildlife, infiltrate the animal world to explore their complex emotions'. '.strtoupper('t')he latest series explores mass gatherings among the animal kingdom as its even more lifelike spy creatures infiltrate communities and take you into the heart of the action'. '.strtoupper('w')hy do animals gather for one off events'? '.strtoupper('w')hat does it feel like to be part of the herd'? '.strtoupper('a')nd how do they cope with the changing seasons and climate'? '.strtoupper('b')ecome part of a gorilla family for the day, discover the drama of koala breeding season, and feel the heat of battle as komodo dragons battle for supremacy'. '.strtoupper('i')n this series, the spies infiltrate a hippo pod, a nursery of red flying foxes and the secret world of pygmy forest elephants.