Why is it that lions, alone amongst all the wild cats, are so intensely social? This programme looks in turn at the possibilities from co-operative hunting to raising cubs, and explores the lion's world from their point of view. Whilst there are obvious benefits to living in prides none seem to be a satisfactory reason to evolve sociality. After 30 years, the Serengeti Lion Project, lead by Craig Packer, may have finally found the answer to the conundrum. The answer could have direct consequences for the survival of lions as a species.