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

Here is Why You Need An Adapter

The outlet and plug type used in Mauritania is C and in Uruguay are C, F and L. This is how they look like.

Uruguay

In Uruguay, outlets of type C, F and L are in use.

Type C

Type F

Type L

Mauritania

In Mauritania, outlets of type C are in use.

Type C