WILDLIFE MANAGEMENT - BLACKBACKED JACKAL
The black-backed jackal: know your problem animal
D.T. Rowe-Rowe KwaZulu-Natal Nature Conservation Service

The most successful hunters and trappers are those that have a sound knowledge of the habits of their quarry. The same applies to problem animal control: an understanding of the animal and positive identification of the predator responsible for the damage will help in efforts to eliminate the culprit. The black-backed jackal, Canis mesomelas, is one of South Africa’s most controversial carnivores.

The mere mention of its name is enough to throw many a sheep farmer into a fit of rage because of the reputation this jackal has gained as a killer of sheep. On the other hand, a grain farmer may not share the sheep farmer’s aversion, as he values any animal that preys on rodents.
Size and development

Adult jackals weigh between 6 and 11 Kg, with 8Kg being the average in most parts of Southern Africa. By the age of 6 months, young jackals have acquired all of their permanent teeth, and by the age of 12 months, they have almost reached full adult size.

Ecology
Black-backed jackals are distributed throughout South Africa, occurring in our deserts as well as in the high-rainfall grasslands, and from sea level to the summit of the Drakensberg. The jackal’s high degree of habitat tolerance and adaptability is well illustrated by the diet that differs from one region to the next.
In the most arid parts of the country jackals eat a high proportion of insects, whereas in high rainfall grassland regions, rodents form bulk of the diet. Wherever large amounts of carrion are available the jackal resorts to this food source, and takes advantage of opportunities, when they occur, to overpower and kill conveniently sized mammals such as hares, newborn antelope, or sheep (mostly lambs). So adaptable is the jackal that it will even feed on fallen fruit.

From a study done in a grassland region, of the Drakensberg, it has been estimated that in that particular area each jackal is capable of consuming approximately 1500 field mice or 500 vlei rats per year.

Habits
Until a few years ago little was known about the jackal other than details of its diet and that it caused problems in some sheep-farming areas. Radio telemetry, however, has made it possible to find out a great deal about the private life of an animal, which although widespread, is wary and secretive.

Black-backed jackals are predominantly nocturnal. Where they are not hunted, their activity starts just before sundown and reaches a peak shortly after dark. A second activity peak occurs shortly before sunrise. Jackals generally spend the daylight hours dozing and sleeping. In hot weather they lie in the shade, but when it is fine and cool, they lie in the sun. They very seldom lie in holes during the day.

Pair bonds are formed by jackals which are usually three years of age or older. Once mated, the pair remains together until one of the partner’s dies. When one partner dies the remaining individual wanders over a large area outside its territory, looking for a new mate. Most jackals’ pups are born during late winter or early spring, which is probably because this is the time of year when most carrion is available.

Initially the female suckles the pups, but they start to feed on solids at an early age and the adults then regurgitate food for them. Both parents feed and care for the young.

During the first 14 weeks of their lives, the pups remain in or around the natal den, which is usually a hole in the ground, then begin to forage with the parents. Although the average litter numbers five (litters of 2 to 8 have been recorded), it is seldom that more than one or two pups survive beyond the age of fourteen weeks. The number of surviving pups is largely dependent on the amount of food that can be provided during the early stages of their lives.

Mated pairs are territorial with both males and females defending the territory: males defending it against other mated males, and mated females defending it against mated females. When a young jackal reaches the age of a year it may remain within the parent pair’s territory and help them to feed and protect the next litter, or it may become a solitary wandering animal.

One of the primary factors that govern territory size, home range size, and jackal density is the amount of food. In the course of research done on jackals in Giants Castle Game Reserve in the Drakensberg of KwaZulu-Natal, it was found that the average size of mated pairs’ territory was 1900 ha. Immature jackals which were less than a year old, occupied ranges of about 900 ha within those of the mated pair, and the average home range size of a solitary non-breeding jackals was 3300 ha.
But what do these figures mean in terms of the total density of jackals?
It was estimated that in Giant’s Castle Game Reserve there is approximately one jackal pr 250 to 290 ha. The only other known density figure is reported from the Serengeti in Tanzania, where it was estimated that black-backed jackals occur at a density of one per 200 ha. Information from a study done in the Western Transvaal indicates that densities on farmland are lower. Sometimes jackals gather at large carcasses in numbers, which might create the impression that densities are higher. Such aggregations include jackals from more than one territory.

There are thus four components in black-baked jackal social groups: the progeny of the year; helpers which improve pup survival; and solitary non-breeding, non-territorial animals (some of which may previously have served as helpers). Solitary adults probably act as a reserve breeding population. The time at which they bear young will depend on the availability of food and territory. Apparently, very few black-baked jackals live longer than six or seven years. If jackals enter the breeding population at approximately three years of age, then by the time that a pair is six years old, their first progeny will be of breeding age.

The knowledge gained from the study of the social organisation of the jackal leads to a better understanding of this predator. As is the case with many other carnivores, the black-baked jackal is at the end of a food chain. So, although widespread and common in many areas, food is the limiting factor. The social system, which has evolved in jackals, ensures that there is sufficient food to go round and that the species continues to exist.

Damage and damage identification
Predation by black-backed jackals on sheep tends to be seasonal, coinciding with the periods following lambing: the jackals killing mainly lambs up to the age of three or four months. The prey is killed and fed upon in a stereotyped manner. The jackal bites at the throat, on either side of the windpipe and retains its grip until the sheep dies of suffocation.

The jackal opens the carcase on the flank between the hip and the bottom of the ribs. The parts eaten are usually the kidneys, liver, heart and the tips of the ribs. The amount eaten is small (up to about 500g) and no large bones are consumed. The jackal is a very neat feeder capable of removing the flesh under the skin; therefore the remains have a hollowed out appearance. It does not move the cascass, and seldom returns to feed on it again. Occasionally small portions are carried away for the pups.

Often the only external signs of the throat bite are two small punctures on either side of the windpipe. Sometimes, mainly where very small lambs are the prey, the upper canine teeth penetrate the skull just below the eye and at the base of the jaw or below the ear. In many instances traces of the punctures are difficult to locate from the outside and it is best to skin the head and neck so as to be able to examine the inside of the skin and the flesh. When skinning the first incision should be made along the back of the neck so as not to cut through the area, which has been bitten. The punctures or bruises made by the upper and lower canines are then visible on the inside of the skin and in the flesh.

If the tooth marks are distinct, then the distance between the upper canine punctures or bruises can be used as additional aid to predator identification. Black-backed jackals have upper canines, which are 23 to 30 mm-apart (average 26mm).

Some dogs have killing and feeding patterns that closely resemble those of the black-backed jackal. It is therefore advisable to skin the whole of the carcass to see where it was bitten and to determine the bite sizes. Dogs of the size of a Border collie upwards have upper canines which are between 35 and 60 mm apart, and dogs often bite at the sheep’s back, flanks, or hind legs in addition to the neck or throat.

A detailed guide on determining carnivores responsible for killing small livestock is available from your local nature conservation department.

Damage prevention
The only known successful method of damage prevention is that of excluding jackals from the property, combined with controlling those on the property. In the drier regions of Southern Africa, the traditional method of exclusion has been the erection of wire-netting fences with stone packs to prevent animals crawling underneath. More recently, success has been achieved using electric fences. Seven or eight strand stock fences incorporating three electrified wires have proved to be adequate to exclude jackals and dogs. Fences must be carefully maintained: wire netting must be regularly checked for holes and electric fencing constantly monitored for short circuits.

Your local nature conservation officer will be able to provide you with electrical fence specification and the names of suppliers.

Control
The black-backed jackal is so adaptable and its reproductive capacity is such that it is usually futile to attempt to completely eradicate them from an area. If possible, control should be aimed at the individuals that are causing the damage.

Effective control measures for jackals are killing them with humane coyote getters, trapping them in gin traps (slagysters), or hunting them with hounds. It is not possible in an article of this nature to provide complete guidelines on the use of these measures, and furthermore, regulations governing their use are not the same in all of the provinces. Anyone interested in employing these control measures should apply to the local nature conservation department.

Control measures can only be as successful as the skill of the user - or ‘its’ not what you do, but how you do it!’ There is no substitute for experience and people will only fully understand the techniques and become proficient in the application of control methods if they attend courses or spend time in the field with experienced workers.