- Nidoran were the first Pokémon to feature gender, and even gender differences; however, their differences are much greater than those of most later Pokémon.
- Despite the addition of genders to most Pokémon starting in Generation II, the two variations of Nidoran remained separate species, rather than a singular species that splits down different evolution paths based on gender.
- Nidoran♀ is the only Pokémon that loses the ability to breed upon evolution.
- Nidoran♀'s alternate coloration is similar to Nidoran♂'s normal coloration, and vice versa for Nidoran♂.
- Nidoran♀ and its evolution share their category with their male counterparts Nidoran♂ and Nidorino. They are all known as the Poison Pin Pokémon.
- Due to the fact that its gender, ♀, is included in its name, checking Nidoran♀'s summary from Generation II onward will display as if it were genderless if it does not have a nickname. If its nickname is anything other than "Nidoran♀", its gender will appear as normal.
