Same species compete. (Within species.)
This is competition within the same species.
Another way to help you remember what intraspecific competition is:
Intraspecific contains the letter a in the middle of it, as does ‘same’.
So intraspecific competition is the same species in competition.
Intraspecific competition occurs between stags for the right to mate with the female deer.
Grizzly bears engage in intraspecific competition for the right to occupy the best fishing spots during the salmon season.