Large carnivores that hunt prey in harmony

Large carnivores that hunt prey in harmony

Sharing resources

Large carnivores that hunt prey in harmony
How often do tigers attack and kill leopards? Or are a pack of wild dogs up for a stand-off with a tiger? There have been several such documented anecdotes in the past. “They returned by noon bringing a few fragments of tiger skin, to report that the dogs had finally cornered their exhausted quarry about five miles away and had literally torn the tigress to pieces. As far as they could gather, five dogs had been killed in the final battle, after which the victors had eaten the tigress,” recounts Kenneth Anderson in his book, Nine Man-eaters and One Rogue, in which he shares the story of a pack of wild dogs taking on a tigress in the Nilgiris. However, a recent study in Karnataka shows how the three predators, the tiger, leopard and the dhole co-exist and smartly avoid each other in the forests.

Home to several species of large carnivores — the forests of Karnataka are no different. Three large predators: tigers, leopards and dholes share resources in the same forests. A recent study conducted by scientists from Wildlife Conservation Society, India proves that not only do these three predators hunt common prey, but also live in harmony. Over 500 camera traps were set-up in five reserves — Bandipur, Nagarahole, Biligiri Rangaswamy Temple, Bhadra and Wayanad — that support large densities of ungulate prey like chital, sambar and wild boar. “We looked at three aspects — one, when animals are active through the day; two, within each reserve, if they avoided each other in space, and three, if they actively avoided each other,” explains Dr Divya Vasudev, one of the study’s authors.

Modifying behaviour
Across the sites, tigers, leopards and dholes displayed remarkable ability to modify their behaviour based on prey density in the area and on the population of its competitors. In the study — published in the journal, Proceedings of the Royal Society of London, Biological Sciences — the authors highlight how these predators have adapted, and changed their hunting habits to avoid each other.

This observation is not common in protected areas elsewhere. For instance, in a recent paper published in Ecology and Evolution, scientists highlight how the population of leopards in Maputaland in Southern Africa decreased with abundance of the top predator, the lion. Yet, in several other places, such co-existence is common.

Interestingly, the study observed that all three predators carve out a little space for themselves, where they are active, and hunt. Take for instance, Bhadra, a forest with low prey densities. “All the animals were much more active throughout the day in this site, probably to maximise their chances of getting low density prey. Since the carnivores themselves were also at a  lower density, Bhadra also showed some overlap in the times of activity. The animals, relatively speaking, didn’t avoid each other to the extent they did in the other parks,” states Divya.

Take the dholes for example — these wild dogs usually hunt during the day, unlike the tigers and leopards. But in Bhadra, the dholes were relatively more nocturnal, and leopards were active during the day too. Similarly, in high density reserves like Nagarahole and Bandipur, the leopards preferred to sneak out in twilight. This kind of behaviour has been documented and observed in several other sites like in the case of wild dogs in South Africa. It has been found that wild dogs avoid lions, particularly during denning. However, they did not exhibit the same behaviour with spotted hyenas found in the same areas as wild dogs are capable of adequately defending their kills from the hyenas.

The impact
Across the globe, scientists are using camera traps to identify causes affecting population densities and distribution of species. Understanding co-existence among species continues to contribute valuable literature to evolutionary ecology, which in today’s world has played a critical role in protecting several flagship species.

Can human presence and interactions change or impact this harmony? Yes. In fact, several studies have proved this over the years. Quite recently, scientists using motion-detecting camera traps to examine spatial and temporal patterns of meso and apex predator occupancy and activity in a fragmented landscape in California, USA  showed how human development and activity alter predator community structure through both direct and indirect pathways.

All five study areas picked by the scientists host large predators within national parks. “First of all, by reducing the space available for large carnivores, the issue of the carnivores living in the same reserves becomes all the more current and relevant. In many parks of India, anthropogenic factors have led to a reduction in prey availability. This again causes differences in their behaviour,” reinstates Divya. Like in the case of Bhadra, with low prey density, the need to be active for longer parts of the day increases. This means the predators cannot easily avoid each other. “On the flip side, intense conservation efforts, like in Nagarahole, have led to high densities of both the carnivores and their prey,” adds Divya.