It is easy for us to imagine two lions fighting for their position within the herd, or a hyena and a vulture fighting for a piece of meat. But what do you know about competition between herbivores in nature?
Competition between herbivores
The concept of “competition” is widely used by biologists to refer to the natural instinct of wild animals to compete. It occurs both between different species and between individuals of the same species.
In Colorado, for example, there are three different species of cheekbone rat (a type of rat) – Geomys, Cratogeomys and Thomomys spp., Which all compete for the same territory.
A good indicator of competition between two species is the ability of one species to occupy the territory of the rival when that species is absent. This is the case with two species of ground squirrel : Eutamias dorsalis and Eutamias umbrinus . Although Eutamias dorsalis is the dominant species, Eutamias umbrinus can compete with it if the trees in the area grow densely.
In Kenya, two species of hares live – Lepus capensis and Lepus crawshayi side by side near the Great Rift Valley. There are often fires in the region, which changes the habitat of both species. This means that L. capensis will dominate over L. crawshayi, as the former moves better in open terrain. But, when the shrubs grow again, L. crawshayi will again dominate.
Competition between herbivores: rabbits and hares
Before human intervention, the European hare ( Lepus europaeus ) had never crossed the Pyrenees. The European rabbit ( Oryctolagus cuniculus ) lived on the Iberian Peninsula, along with the Iberian hare ( Lepus gratantensis). But over the years, the distribution of the European rabbit and hare began to coincide, and both spread over large parts of Europe, South America and Oceania. With the exception of Australia, the hare is much more widespread than the rabbit.
Somehow an allopatric species formation has taken place between these two species. This means that both prefer a certain kind of living environment. Rabbits, on the other hand, prefer sandy and clay soils, coniferous forests and grasslands. While hares prefer arable land, cornfields, dunes and forest clearings.
In the countryside it has always been thought that hares and rabbits avoid each other. The belief may have arisen because rabbits will hunt and tease hares until they become tired, as the rabbits have the upper hand in terms of the number of individuals. Experts believe this is one of the reasons why rabbits perform so much better than hares in Australia. But despite the rumor, you can see hares and rabbits eating side by side on all continents.
Why is it that the more rabbits, the fewer hares?
The rabbit plague, which caused thousands of dead rabbits across Europe in the 1950s, teaches us a great deal about how rabbits and hares interact with each other.
There are many reports of conflicts between rabbits and hares, both in captivity and in the wild. There have also been many cases where rabbits have attacked hares over the centuries. Nevertheless, they have also been seen sharing territories and eating peacefully side by side.
Studies show that there is normally no aggressive behavior between the two species. Hares do not usually escape rabbit attacks. Nor do they avoid the areas inhabited by rabbits, or rabbits in general. This means that there is no direct reason for them to compete with each other. One species can live in one part of the territory, and the other species can simply live in another place.
There are reports of diseases, which are usually unique in rabbits, and which have been shown to be fatal in hares and vice versa. For example, the parasite Graphidium strigosum initially infected only rabbits. However, it later turned out that when a hare entered a territory with infected rabbits, it was also affected.
Competition between herbivores: conclusions
The European rabbit and the hare have only recently begun to live side by side. One of the explanations for their previous competitive behavior is that they were at the beginning of the process of adapting to the new coexistence.
Because their food is relatively similar, experience shows us that they can live together without major problems, if they find food in different areas. But if one species is missing from the site, the other will take its place.