diff --git a/include/pokemon.h b/include/pokemon.h
index 07bcff2e3..ec125573c 100644
--- a/include/pokemon.h
+++ b/include/pokemon.h
@@ -506,7 +506,7 @@ u8 CalculatePlayerPartyCount(void);
 u8 CalculateEnemyPartyCount(void);
 u8 GetMonsStateToDoubles(void);
 u8 GetMonsStateToDoubles_2(void);
-u8 GetAbilityBySpecies(u16 species, bool8 abilityNum);
+u8 GetAbilityBySpecies(u16 species, u8 abilityNum);
 u8 GetMonAbility(struct Pokemon *mon);
 void CreateSecretBaseEnemyParty(struct SecretBase *secretBaseRecord);
 u8 GetSecretBaseTrainerPicIndex(void);
diff --git a/src/pokemon.c b/src/pokemon.c
index cb7be1715..df31bc6b3 100644
--- a/src/pokemon.c
+++ b/src/pokemon.c
@@ -4424,7 +4424,7 @@ u8 GetMonsStateToDoubles_2(void)
     return (aliveCount > 1) ? PLAYER_HAS_TWO_USABLE_MONS : PLAYER_HAS_ONE_USABLE_MON;
 }
 
-u8 GetAbilityBySpecies(u16 species, bool8 abilityNum)
+u8 GetAbilityBySpecies(u16 species, u8 abilityNum)
 {
     if (abilityNum)
         gLastUsedAbility = gBaseStats[species].abilities[1];