Sociable and smart are not words that usually come to mind when Spotted Hyaenas (Crocuta crocuta) are mentioned. If anything, hyaenas are seen as sneaky and vicious, cringing scavengers that inspire a queasy mixture of fear and disdain. Yet, after spending 20 years studying them, Professor Kay Holekamp from Michigan State University came to view them as “smart, biologically and socially complex, jam-packed with surprises”. Having had the opportunity to observe a den first-hand, I, too, have become fascinated with these multifaceted predators and their unique biology and behaviour.
First among their Pandora’s Box of surprises is that although they resemble dogs, all four hyaena species are actually more closely related to cats − their common ancestor being a cat-like tree dweller which also gave rise to mongooses and civets. Ultimately, hyaenas are hyaenas, or (more scientifically) four species in the very specialised family of Hyaenidae. They share biological ancestors with cats, but developed to be more like dogs.
The communal den is the centre of social life to a spotted hyaena clan. A pregnant hyaena goes off alone to give birth, then moves her cubs to the communal den when they’re a few weeks old − by which time they have learned her scent.
Interestingly, the cubs are born with their eyes open and some of their teeth already erupted. The den is usually adapted from an aardvark burrow, and has multiple entrances connected by tunnels dug by the cubs.
Hyaena cubs are cute! Yes, you read that correctly: cute! Resembling small bears with Mickey Mouse ears, they are completely black in colour at birth. When they are two months old, the head and neck become lighter, and spots appear at around four months. The legs, however, remain dark until the cub is at least a year old.
Mothers are extremely protective of their cubs and may suckle them until they are 18 months old. The milk of spotted hyaenas is documented as being the most nutritious and protein-rich of all terrestrial mammals. Only the milk of polar bears and sea-otters has a greater fat content. For the first 9 months, the cubs are totally dependent on their mother’s milk, after which they start visiting kills and consuming solid food.
Spotted hyaenas sometimes scavenge, but (contrary to popular belief) they kill 95 percent of their food. As hunters, alone or in groups, they equal leopards and lions. An adult spotted hyaena can tear off and swallow an astonishing 14kg of meat per feeding. To a hyaena, almost anything organic is edible, including (as I know from personal experience) leather shoes and cotton sheets!
Spotted hyaenas are also gender-benders and role reversers! Females are bigger and more aggressive than males, and have more testosterone than any other female mammal. Every clan is a matriarchy, ruled by an alpha female. In the clan’s strict power structure, all males will rank lower than every female, including female cubs. At a communal carcass, adult males eat last – if there’s anything left. When a male kills dinner on his own, he must gorge quickly before female clan members push him aside.
If that’s not enough to convince you of their deviation from the traditional male-dominated predator hierarchy, then take a slightly closer look. In so doing, you will notice that it is impossible to tell male from female, since the female’s external reproductive organ resembles that of the male. Called a pseudopenis, it comprises a tube-like clitoris with fused labia that gives the illusion of a penis and scrotum. Through this structure, female hyaenas urinate, mate, and even give birth.
So, why do females have, as Holekamp calls them, “these bizarre structures”? It would seem that the most plausible answer is to maintain power over reproduction. Mating is impossible without full female co-operation. And, if a female changes her mind about a male after mating, the elongated reproductive tract allows her to flush out the sperm by urinating.
Hyaenas have a complex behavioural language. Casual hellos include nuzzles, body rubs and muzzle licks. More formally, a subordinate animal will nervously lift its hind leg to expose its erect penis or pseudopenis for the dominant animal to sniff or lick. Other deferential gestures include giggling, head-bobbing and grovelling. Spotted hyaenas have some 14 different calls in total, including the well-known ‘eerie cackle’ which they emit when stressed or excited.
Hyaenas are also proving to be very smart – in some ways, as smart as primates, according to Holekamp’s research. She notes that “…they live in societies as complex as those of some primates and seem to show as much social intelligence. Like primates, they learn and follow rules of social status and behaviour, and they solve social problems in ingenious ways, using distraction, deception or conciliation.”
With all of this in mind, I hope that the next time you are fortunate enough to encounter a hyaena clan, you put aside the stereotypical perception of brutish thugs and see them instead as unique, complex and intelligent animals about which much is still to be learned.
By Lorraine Doyle