You Do Need power plug adapter while traveling from South Africa to Mauritania.

Here is Why You Need An Adapter

The outlet and plug type used in Mauritania is C and in South Africa are C, M and N. This is how they look like.

South Africa

In South Africa, outlets of type C, M and N are in use.

Type C

Type M

Type N

Mauritania

In Mauritania, outlets of type C are in use.

Type C