Human presence alters the balance between leopards and hyenas in East Africa

Who is stronger? A lone leopard or hyena prank? And what is the best way to get along with people?

Researchers at the University of Copenhagen studied this closely in a large natural area of ​​East Africa surrounded by rural settlements. The study published in Ecospheredemonstrates that the presence of humans has a direct impact on the competitive relationship between two large predatory species: leopards (Panthera pardus) – iconic spotted cats and spotted hyenas (Crocuta crocuta) – a kleptoparasitic and pack hunter known for its humor . appearance and characteristic “laughter”.

“We humans continue to eat what’s left of the world’s wilderness. As we do, we impact wildlife. This study shows that human disturbance disrupts the balance between competing species and that this benefits hyenas,” says Rasmus W. Havmøller. , first author of the study and a postdoctoral fellow at the Natural History Museum of the University of Copenhagen in Denmark.

For months, Havmøller has been using camera traps to observe the dynamics between hyenas and leopards living in Tanzania’s Udzungwa Mountains – roughly 2,000 km² national park that is completely surrounded by agricultural and populated areas. The study is the first to combine camera observations of large predators in both time and space in a single analysis.

While hyenas as a species appear to be increasing in numbers, leopard populations have been in significant decline for decades, both in Africa and around the world. Since hyenas are the only competitor of leopards in this particular natural area, the ability of the two species to coexist is important for their survival. And here, the local population is an important factor.

“Since the local people don’t like leopards, the leopards retreat as far away from people as possible. Hyenas, on the other hand, benefit from the fact that people don’t feel threatened or chase them. As a result, hyenas live close human populations and may even use humans as shields against leopards,” says Havmøller.

“But the areas closest to humans are also the areas with the most prey. And as hyenas assert dominance over these areas, this increases their ability to outcompete leopards and potentially threatens the leopard’s fitness,” adds Havmøller.

Measure matters

The researchers’ observations confirm that size matters. While male leopards, who are larger, maintain their dominance over hyenas, the situation is different for female leopards, who are smaller.

“Even though the male leopards are the ones in charge, the hyenas aren’t exactly scared of them. They just stay in the background – maybe to follow the leopards and steal their prey. But the hyenas’ physical inferiority seems to be compensated for in the closer quarters people, because male leopards retreat,” says Havmøller.

“Female leopards, on the other hand, completely change their behavior when hyenas are in the area. They become diurnal, while hyenas are mostly nocturnal. This is probably because female leopards are smaller than hyenas and that they are likely to lose in every war. on the prey”.

Overall, the study shows that hyenas benefit from living near humans.

“This suggests that hyenas’ ability to adapt to areas of human activity may strengthen their overall success as a species and their competitive advantage over other large predators as we humans increasingly disturb nature,” says Havmøller.

When leopards are under pressure, cascading effects can follow

According to the researcher, the change in the hunting patterns of the female leopard could have negative consequences. “If you open up to more tourism and build more roads in the national park, female leopards will immediately come under pressure. They are unable to distinguish between safari tourists – who are more active during the day – and poachers.

“Over time, they will probably learn that the safari guests are not dangerous. But if there is a large and rapid influx into the area, you will probably see a decline in their population,” says Havmøller.

If leopards are seriously suppressed in the food chain, what are known as cascade effects in the ecosystem should be expected. “The uprooting of a large predator like the leopard from a food chain, which may be the ultimate consequence of human disturbance, can have very violent effects.

“Populations of other species, such as certain monkeys whose populations are kept in check by leopards, will suddenly become very large and change the balance of the entire ecosystem,” says the researcher.

As such, Havmøller hopes the study will serve to encourage restraint when it comes to managing wilderness areas.

“Our results clearly show that human disturbance can change the competitive relationship between important predators. So, I hope they will be taken into account when expanding activities in wilderness areas, so that they spread slowly and give the animals a chance to adapt.

“Furthermore, it would be good to monitor the effects of human disturbance in more places using camera traps,” concludes Havmøller.

Hyenas vs Leopards

• Leopards are unpopular among local residents in many countries because they can hunt livestock and attack people. On the other hand, hyenas “cleanse” themselves by eating sick or dead livestock and do not pose a problem to humans.
• Female leopards (about 20 kg–43 kg) are about half the size of male leopards (about 51 kg–72 kg). Hyenas are in the middle in weight (approximately 48 kg–56 kg).
• Leopards are solitary hunters, while hyenas hunt in kakari (clans), which can be an advantage for hyenas in confrontations with leopards.
• Hyenas are kleptoparasites that regularly steal the prey of other carnivores, including leopards.
• On the other hand, leopards are master tree climbers, which allows them to protect their prey from hyenas.