There is a female hidden in the back of a closed van in the Service road area. There are no items to be obtained in the van, but opening the doors will release the female. Thus, opening the doors is not recommended, unless you have to take a Special Item which forces you to open them. Thankfully, only David King will need to do this and only on Normal mode.
After the male has been killed on hard and very hard modes, any females in the area can still attack the player. However, the player does not have to kill them in order to end the scenario.
On the Hard difficulty, the male will be accompanied by a lioness, while on the Very Hard difficulty he will be accompanied by two lionesses, making his fight a lot more dangerous than Zombie Elephant's.