This proverb is based on one of the many African folk tales/fables. This particular fable tells the story of a time when all animals did not tails. When the time came for the animals to get tails, they were told to go to a certain place at a particular time to get their tails. The rock-rabbit however instructed other animals to bring it a tail. Because every animal was preoccupied with choosing their own tails, none remembered the rock-rabbit until it was too late. Hence to this day the rock-rabbit has no tail. From this fable our ancestors stressed the importance of not delegating tasks that are one’s primary responsibility. If the task is ultimately not performed as expected or is not done at all, the person who is responsible for the task is always held accountable whether or not they delegated the duty.
The proverb is used to encourage people to avoid delegating their primary responsibilities in order to ensure that tasks are accomplished according to specifications. If someone is delegated or asked to do something which is not their key result area, chances are that they may not give the task the priority it deserves hence the proverb can also be used to explain that shortfall in execution.