The boys welcome some new arrivals to the zoo. Mimo the Pygmy Marmoset emerges from its nest box for the first time and two penguin chicks hatch. Meanwhile, it’s Tilly the red panda’s birthday, and to celebrate, the brothers decide to hold a cake-off. It’s a tradition at the zoo that when a new animal in born, all the animals get presents. Finally, we catch up with the boys in Rwanda as they meet wildlife heroes fighting to save the planet’s largest primates - the mountain gorilla.