Lions are strangely social, the only wild cats to live in family groups. Lion expert and BBC Big Cat Diary presenter Jonathan Scott investigates the reason why with the help of the most famous lion pride in the world - the Marsh Pride of the Masai Mara in East Africa. Jonathan's intimate knowledge of this massive pride and their various sub-groups helps him explore the possible reasons for the lion's social lifestyle. While there are some apparent benefits to living in prides, from co-operative hunting to raising cubs, none appear to be a reason enough to evolve social living. Now, after 30 years of intensive study, the Serengeti Lion Project, lead by Professor Craig Packer, may have finally found the answer and it could have direct consequences for the survival of the lion as a species.

The lion's social nature makes it both complicated and fascinating. Lion expert and BBC Big Cat presenter, Jonathan Scott, has lived in Kenya, in East Africa, and watched the most famous lion pride in the world, the Marsh Pride, for more than 30 years. With the help of the latest lion research from Professor Craig Packer and his team at the Serengeti Lion Project, Jonathan takes a fresh look at the lions he knows so well.

He reveals why male lions have a mane, why murderous step-fathers are an important part of lion family life and discovers why being social brings unique challenges for the survival of the species as a whole. Living in prides once helped the lion to be the most widespread land mammal on Earth after humans, but now it could be their downfall as they are increasingly restricted to small parts of Africa.