Living with predators
Many people, when hearing the word “predator”, immediately have a vision of “dangerous animals” that are hell bent on injuring them or destroying their domestic livestock or pets.
These animals have lived in Africa throughout mankind’s long history. Fossil evidence has revealed that leopards and lion once preyed upon early humans, regarding them as a food source just like other animals. As humans evolved they became more socially organised and started making tools with which to hunt. These large predators then became the prey of humans using spears and arrows. The predators then stopped being a menace to human life and predators and humans lived in a state of truce where they left each other alone except for occasions when domestic livestock presented too tempting a target for the predators, or when young humans young men proved their “manhood” by killing one of the magnificent large predators such as lion or leopard.
The arrival of the first European settlers and their firearms change the peaceful relationship between man and predator to one of active warfare. The white settlers had a strong belief that all predators were an obstacle to their farming and had to be removed if the African continent was to be “tamed and civilised”. Any predators were shot on sight wherever they were found so that domestic livestock might safely inhabit areas where wild animals once roamed. This resulted in the situation that exists today where most of the bigger predators are mainly confined to game reserves and national parks where they hardly ever come into contact with domestic livestock. However, some predators still exist in a few areas outside the proclaimed game reserves and parks – one of these places is the Lower Mpushini Valley Conservancy where the local landowners have united to protect all wild creatures, including the predators that still exist in this beautiful area.
The ecological role of predators
Many people are under the misconception that all predators are exclusively meat-eater. This is not so. Many, such as the Civit and Black-backed Jackal, are sometimes omnivorous, eating both animal and vegetable matter. Some are insectivorous, such as the Aardvark that lives almost entirely on termites.
Meat-eating predators kill their prey in various ways. Civits, mongooses and genets bite into the back of the head and crush their victim’s skull resulting in almost instantaneous death. The big cats kill small prey by sinking their canine teeth into the neck and forcing the vertebrae apart, or large prey by strangling or suffocation with a bite that is directed at the throat or over the nose and mouth of the victim. However, we should always remember that predators kill out of necessity – it is only man that kills out of anger or vindictiveness!
Predators vary greatly in size and they also have a wide range of diets and hunting methods. The social behaviour of the different species also varies. The solitary leopard and caracal seldom socialise with their own species other than to mate.
Carnivorous predators are ecologically important because they are at the top of the food chain. They play a vital role in controlling and managing their prey by cropping surplus animals. This results in a healthy and viable prey population and prevents areas from becoming over utilised. At the same time, any disturbance in the ecosystem will affect those animals at the top of the food chain, thus making carnivores more vulnerable than other species. It is not by chance that many carnivores are rare or endangered.
The numbers of most predators are limited by the available food supply. This means that they are unlikely to eliminate prey populations. The balance between predator and prey is therefore a delicate one. The struggle between predator and prey has a major effect on the evolution of both: the strong, the quick and the efficient survive, while the weak, the dull and the slow are eliminated.
Not only is there a fine balance between predator and prey, but predators affect one another through competition. In closely related species, the larger may dominate the smaller one and keep its numbers in check. There are indications that the caracal has taken over from the leopard in many parts of South Africa.
Human relationships with predators is one of extremes. Humans have befriended and domesticated the dog and the cat, they have also, at the same time, decimated or even exterminated some species.
As the predator’s habitats dwindle due to human activities and their populations become even more fragile, the fate of many species of predators is in our hands. We must decide whether these fascinating and beautiful creatures are to live or die due to our actions.
The benefits of having predators on farmland
The extermination of most of the large predators came about as a result of the archaic idea that all predators are bad and should be killed wherever they are found. This idea is still in the minds of of some of the modern farmers. Despite this, predators do have a valuable role to play on the farm.
Extensive research into the different species of predators that occur on farmland has shown that their main prey is rodents and insects. The predators perform a vital role in controlling the numbers of rodents. Without the predators rodent numbers might rise to levels where substantial crop damage could occur causing greater financial loss than the occasional attacks on small livestock. An excessive number of rodents can affect the condition of the veld and its regeneration due to the consumption of vast quantities of grass seeds.
Rodents, hares, dassies, and insects, which form the main part of the diet of predators that are accused of stock killing, can remove a large quantity that would normally be used by livestock. Thus, if a Jackal were to kill one sheep and the farmer were to respond by killing all predators on his farm, he might be reducing his income more by allowing the rodents, dassies, hares and insects to increase. These would remove more grazing for a greater number of livestock than were killed by the predators.
Predators, being at the apex of the food pyramid, indicate the effects of environmental degradation by declining in numbers. The presence of a variety of predators can be an indication of a balanced ecosystem as a result of wise land use management. The aesthetic value of predators, especially the smaller rare species may instil an inner satisfaction in the farmer in knowing that his activities are in harmony with nature.
Livestock losses due to predators
Certain predators do kill small livestock such as sheep, goats, calves, and occasional adult cattle. Free-range poultry are also susceptible to predation by small carnivores such as genets and mongooses. To a predator any animal or bird, whether it is domesticated or wild, is seen as a food source. In some cases these losses to predators can cause substantial financial losses to the farmer.
The economic impact of predation to individual farmers comprises direct and indirect costs. Direct costs are the loss of market value of the stock killed, veterinary care of injured stock, replacement of breeding stock, and reduced profits. Indirect costs are those due to predator control, measures taken to protect stock from attacks such as locking up stock at night, disease spread in kraals, fleece damage caused by animals being kept in closely confined quarters, and so on.
Predator control measures are usually implemented to reduce both direct and indirect costs. The farmer should conduct detailed cost-benefit analysis to determine the real effect of predation losses and the cost of predator control on his operation before implementing any control methods. Control costs should never exceed losses through predation. The farmer may find that he can live certain levels of predation by improving other areas of his farming operation. It is, however, usually necessary to implement some form of predator control.
In the past farmers usually resorted to using poison resulting in the indiscriminate deaths of many non-target species such as vultures. This resulted in an outcry from the conservationist lobby who demanded that the use of poison should be banned.
A knowledge of predator biology can help to improve the efficiency and selectivity of predator control methods and, also, to reduce some of the undesirable consequences of indiscriminate predator removal. The understanding of natural patterns and being able to define predation problems in biological terms is an important aspect of good farm management.
Some farming practices, such as open range stock farming, might unknowingly maintain unnaturally high predator numbers, compounding the livestock loss problem. During late winter and spring the natural prey that is available to predators is very low. This is when natural mechanisms reduce predator numbers to levels that are determined by the availability of natural prey. The old, weak and less fit predators simply perish and fewer young survive. On the other hand, it is at this time of the year that most synchronised lambing takes place. Predators that are hard pressed for food will readily make use of this artificial food source. This accounts for the seasonal nature of predation. If a flock is unprotected during this vulnerable time it will ensure that many more predators this naturally lean period, thereby contributing to unnaturally high predator numbers in the following season. This is compounded for every year that the farmer supplies the predators with this food source in late winter. It is, therefore, vitally important that flocks be protected at lambing time.
