Hyenas are often thought of as vicious and sinister. We have seen them as designated villains in all kinds of media. In reality, these animals live in complex societies and display a lot of socially sophisticated behaviors. They are undoubtedly terrific and vicious hunters, which can make them seem scary in human eyes, but actually, they are fascinating creatures.
Rivalry Between Siblings
Little spotted hyenas are born with opened eyes and already a full set of teeth. For most other carnivores, this is not the case. They are usually born with a twin brother or sister. Right after they are born, they will start to compete for their mothers' milk and can get very aggressive. As soon as the first few weeks, a hierarchy will form, and one of the twins will come out more dominant than the other. Rarely does the dynamic between the twins change later on.
Habitat Plays A Role
In some habitats, such as in the Serengeti, hyenas will not always have stable access to food. Life can be a struggle from early on. It is because animals hyenas prey on migrate and move across vast distances. During this season, a mother hyena will have to leave her little cubs to hunt. She can be away for days and may not have enough milk for both when she returns. If this happens, the less assertive one in many cases dies of starvation when the other cub in the litter will not share.
But for example, when we observe hyenas in other habitats, such as the Ngorongoro Crater, this kind of aggression and competition between siblings is less pronounced. It is because here, food is available, and hyenas can nurse their babies regularly and frequently.
Why Does It Happen?
Access to food will be a great factor in how serious this initial rivalry is, but there are other factors as well. The older twin could have an advantage. This could be because of the time between births. It is around an hour-long, and this is enough time for one the cubs to feed and get a slight upper paw on their sibling right away.
Any pattern that establishes early on is likely to continue simply by learning. If a cub gets used to winning or losing out during nursing, they are likely to accept this as a rule so they will reinforce this dynamic. Accepting the subordinate role has its rewards because it means it will decrease the competitive behavior of the sibling.
The intensity of the dynamic will decrease over time. The dominant twin will be less aggressive, and the subordinate cub will respect the hierarchy in the community leading to a stable pack. Some subordinate twins can, however, increase their access to milk because they will challenge the dominance of their sibling due to hunger. Sex also plays a role. In pairs of brother and sister, the female hyena is more competitive and more likely to become dominant. They are also more likely to reverse the hierarchy in their favor if they do end up subordinate. This may be due to more support from their mothers as hyenas live in matrilineal packs.