Zoo keeper in Cairo has put lions on the birth control pill (also known as emergency contraceptive) following a population explosion.

The number of lions at the zoo rocketed to 35 lions recently. In a bid to control the growth of the pack, zoo keepers have been dishing out birth control tablets with their meals. The controversial decision puts the zoo even further at odds with animal rights campaigners, who were already unhappy with the way animals there were treated.

A worker said: “We gave the lions 2 pills every 15 days and it reduced conception by 30%”

This is not the first time animal experts have used substances intended for humans to arouse animals. Lions at a zoo in America were given Cologne to increase their libidos earlier this year, as it contains pheromones, which naturally help arousal. The news prompted CNN News in America to call the particular brand of perfume, obsession for men, “Viagra for lions”.

Viagra has also been given to sheep, to help them become pregnant, and pandas, to help them mate.

Birth control tablets have been around since the 1960s. The latest development in emergency contraception is ellaOne, a tablet that can prevent pregnancy for up to 5 days after sex. Before ellaOne tablets could only have this effect for up to 72 hours. Emergency contraception works by increasing the amount of progesterone (a naturally occurring chemical) in the body. They are typically known as “morning after pills”, though experts say this is a slight misnomer, because they work when taken before intercourse, and for 3 to 5 days afterwards, depending on the specific medication. It is important to remember that while emergency contraception can prevent pregnancy, it cannot stop sexually transmitted diseases being passed on, as barrier protection like condoms can.