We were busy eating leftovers next to the Sabie River when one of the resident vervet monkeys tried to steal a piece of pork rib from our table. This came as no surprise, for Nkuhlu’s vervets have a reputation of being some of the most cunning in the whole park, relentlessly testing wary visitors’ patience as they dash in to grab whatever they can from plates, picnic baskets or even little hands.
 
What did come as a surprise was the aggression shown by this specific adult female that had her eyes on our pork. It’s not uncommon for large adult males to stand their ground when being chased, but this female would have put any male to shame with her reaction. When we got up and waved our arms at her, she rushed closer with raised eyebrows and teeth clearly visible. The message was clear: She’s in charge here!
 
But then we noticed something peculiar. Next to the two tiny pink nipples grew two large blue testicles, or at least what looked like testicles…on her chest! The blue growths were exactly the shape, colour and size of dominant male vervets’ testicles.

 
Our theory is that this female’s dominance may have resulted in increased levels of testosterone production in her body, resulting in male-like genital growths. This is a well-known occurrence in spotted hyenas where females have genitals that resemble those of the males. This is supposedly a result of high testosterone levels in female hyenas, which are the dominant members of the clan.

 
Advice about monkeys
Remember, vervet monkeys only become a problem because we allow them to. Make sure to discard your rubbish in monkey-proof bins, safely pack away your food when you go on a game drive and never feed the monkeys. If humans don’t provide them with food, they will happily feed on what nature provides them.