In the harsh climate of Antarctica, Adelie penguin siblings take the term 'sibling rivalry' to a new level, their survival depends on it. Pitting the pair against each other will show the parents who is the fittest and most likely to make it in the wild. Subscribe: bit.ly/BBCEarthSub #GrowingUpWild #BabyPenguin #AdeliePenguins Watch more: Planet Earth bit.ly/PlanetEarthPlaylist Blue Planet bit.ly/BluePlanetPlaylist Planet Earth II bit.ly/PlanetEarthIIPlaylist Planet Dinosaur bit.ly/PlanetDinosaurPlaylist Natural World: Growing Up Wild (2015) A look at the challenges young animals face, from their first steps through to leaving home. For any animal, the early days of life are often the most difficult. Finding food, avoiding predators and generally learning life's essential skills is tough. However, with a little parental guidance growing up can be an adventure. By following some special tiger cubs in India, an adolescent mountain gorilla in U...