
Nobody could call it fair, but some spotted hyaenas are born with a proverbial silver spoon in their mouths. First they arrive in the world as females, which gives them an immediate leg-up, living as they do in a matriarchal society where women wear the pants. And since every individual automatically inherits a social rank just below that of its mother, a lucky few are blessed with a station in life vastly superior to their clan mates. Their advantages are particularly apparent at a kill, when they get first dibbs at feeding while lower mortals must wait their turn.
But this strict dominance hierarchy only works if all members of the clan – numbering up to 90 individuals – know where they are in the pecking order. Clearly, they not only have to recognise who’s who by their appearance, odour and voice, but must also understand the more nebulous characteristic of social status. This implies a remarkable capacity for learning that has caught the attention of international teams of behavioural ecologists, who travel to Africa from other continents to conduct years of observational field work.
Kay Holekamp and her graduate students from Michigan State University in the USA have been studying spotted hyaenas for 20 years, and consider them model subjects for testing hypotheses on the evolution of intelligence in mammals. Her team sponsors and maintains the website for the IUCN Hyaena Specialist Group, currently chaired by former SANParks scientist and now freelance consultant Gus Mills, who started his career researching hyaenas in the Kalahari.
In a brief introduction to spotted hyaena life history, they explain how cubs learn their place in society.
“Young hyenas initially direct their aggressive behaviours equally at higher- and lower-ranking individuals. But this changes rapidly during the first year of life, as cubs come to direct aggression only at animals lower-ranking than their own mother.”
Why the change of heart?
“When youngsters become involved in disputes with group-mates, the mother intervenes on their behalf against all individuals lower ranking than herself.“
So if cubs have to fight their own battles when they get into spats with the offspring of higher-ranking mothers, they’ll inevitably come off worse – getting a harsh lesson in social politics in the process. They soon learn their dominant or subordinate status in relation to each and every member of the clan.
By definition, learning is a process that leads to a change in behaviour due to experience. While all animals are born with behaviours that are innate or instinctive – the natural abilities that allow spiders to spin complex webs on first try, for instance, and the knee-jerk reactions that make small mammals flee from sudden noises – some of these ‘fixed action patterns’ could be counter-productive in a changing environment. If they reduce the probability of survival and reproduction, natural selection would wean out these rigid behaviours, but only after many generations. Learning, on the other hand, allows animals to respond and adapt to change in their own lifetime.
In truth, though, the distinction between instinct and learning is not so clear cut, as many instinctive behaviours can be modified by learning, particularly in higher animals. The Austrian ethologist, Konrad Lorenz, famously demonstrated this fuzzy area in a case of imprinting gone wrong in greylag geese. Capitalising on the natural instinct of newborn goslings to fixate on the first moving object they saw during a critical period after hatching, he got the geese to imprint on his boots so that they followed him around long into adulthood.
Essentially, imprinting is a form of rapid learning that takes place at an early point in an animal’s life. It is particularly useful for animals that live in groups, ensuring that young will bond with their mothers, and be able to pick them out in a crowd. In zebras, for example, a mare will keep the rest of the herd at a distance for a few days after giving birth, until her foal has learned to recognise her unique stripe pattern, call and smell.
The much slower processes of acquiring knowledge and changing behaviour that we typically think of as learning, though, can be divided into three broad categories – non-associative, associative and observational learning. The first encompasses the simplest kind of learning, habituation – where an animal gradually become less responsive to a repeated stimulus – as well as its flip-side, sensitisation. Habituation explains why herds of antelope in the Kruger National Park calmly continue grazing when a car approaches. Given the park’s high visitor numbers and extensive road network, they have learned from repeated exposure over time that no harm will come to them from people safely contained in cars.
In associative learning, also known as conditioning, animals make a connection between two events due to some repeated stimulus or reinforcement. The Russian scientist Ivan Pavlov provided the classic example when he incited his dogs to salivate at the sound of a bell, which they had come to associate with food. Likewise, our spotted hyaena cubs learned to behave appropriately for their social rank after repeatedly getting a hiding from the over-protective mothers of dominant clan mates.
Lastly, there’s the “monkey see, monkey do” approach of observational learning. Young animals in particular learn much of the knowledge they need to survive by watching adults and copying their behaviour. This is especially true for animals that live in social groups, or have a long period of dependence on their mothers. Research conducted by Colleen and Keith Begg in the southern Kalahari, for example, showed that honey badger cubs stay with their mothers for a minimum of 14 months, learning how to hunt efficiently. For the first eight months they lack the necessary co-ordination and technique for digging and climbing, while catching rodents and killing poisonous snakes require skills that must be learned from their mothers. Apart from observational learning, there’s probably also some associative learning involved as they are rewarded with food, or told off by their mothers.
“On a few occasions we saw mothers allow their young to catch and fiddle with scorpions that are not poisonous, but actively growl at them when they tried to catch poisonous species,” says Colleen. “We also saw them growl at cubs that attempted to help when digging out poisonous Cape cobras, but there was no similar reaction when they were digging out non-poisonous snakes.”
The Beggs found that the Kalahari honey badgers obtained most of their food by digging for small mammals and reptiles, but more than 40% of these prey items escaped above ground. Being rather slow and cumbersome, the honey badgers were unable to catch these escapees, but a number of other species had learned to tag along on their hunting forays in the hope of an easy meal. The most frequent hanger-on was the pale chanting goshawk – as many as six would be seen following a honey badger at once. What started as an opportunistic behaviour by a few alert birds had evidently spread throughout the goshawk population through a combination of associative and observational learning.
“Juvenile goshawks accompany their parents when foraging,” says Colleen, “so they probably learn that honey badgers are a good source of a free lunch!”
And as all teachers know, there’s nothing quite like a special treat to turn bored pupils into fast learners.