The Untold Story of Hyenas18 September 2017
Like countless other ’90s kids, I first learnt about hyenas from watching The Lion King.
For me, it was not only the best Disney movie ever (except for maybe its sequel #Kiara&KovuForever), it also gave me my entire knowledge of hyenas via Scar’s cackling trio of hyena henchmen – Shenzi, Banzai, and Ed. Yet, while Disney’s representation of hyenas successfully terrified a generation, did its portrayal get anything right?
Although it may seem like a minor detail, Shenzi (voiced by Whoopi Goldberg), the scheming, sassy leader of the trio, is female, and reflects the matrilineal structure of spotted hyena society. Much like the large group of hyenas seen when Scar reveals his evil plan in the song ‘Be Prepared’, hyenas do in fact live in large, loose ‘clans’ of around eighty individuals. In these clans, females outrank males – with high ranking mothers passing on their social status to their children.
Female hyenas are larger and more aggressive than males, and show many traits that are typically masculine in other mammals. However, this dominance comes at a cost, in the form of a bizarre and complicated reproductive system. The female hyena has no external vagina. Instead, her clitoris, through which she urinates, copulates, and gives birth, is over 15 centimetres long. This presents a major problem for first-time hyena mothers. The hole in the ‘pseudopenis’ is only two centimetres wide, and tears during birth to allow the cub’s head to exit. The tear the birth leaves is permanent, yet surprisingly, this is a good thing as it scars in such a way that subsequent births are much easier.
Another problem is the length of the birth canal. At 60 centimetres long, it is twice as long as in other mammals of a similar size. Because the umbilical cord is far shorter than that, the placenta detaches from the uterus while the cub is still in the birth canal, meaning the birth must proceed rapidly to prevent the cub dying from lack of oxygen. No wonder the mortality rate for first-time hyena mothers is 20 per cent.
Now you would think that after all this suffering, evolution would try its hardest to ensure the survival of the remaining cubs … but you would be wrong. Even if the mother survives, around 60 per cent of the cubs will perish during birth. More horrifying though, is the fact that another quarter of the litter will be killed by its own siblings, who are naturally predisposed to violent playing and arguing.
While hyena reproduction makes human birth look easy, the difficulty for these mothers plays a pivotal part in the formation of their incredibly hierarchical society. While testosterone ‘masculinises’ the female’s genitals and reduces their fertility, it is also responsible for their increased size and aggression – two crucial traits in establishing dominance and obtaining as much food as possible. In fact, studies have shown that mothers who release more testosterone during late pregnancy give birth to young that are more aggressive (especially when fighting for food), and hence more successful in the clan when they grow up. The benefits of social dominance outweigh the risk of maternal mortality and reduced fertility.
After all this pain and suffering, there is one nice thing about hyenas – they are smarter than Disney gives them credit for. Far from being slow and dim witted like Ed in The Lion King, real hyenas are highly intelligent. They have a large prefrontal cortex, which is the area of the brain responsible for complex decision making and problem-solving. They even outperform chimpanzees on some intelligence tests, particularly those involving teamwork, and show evidence of counting ability. So don’t be fooled into seeing hyenas as nothing more than giggling numskulls – there’s more to Shenzi, Banzai and Ed than meets the eye.