Diet
Jackals are opportunistic feeders, including a very wide range of food sources such as insects, termites, snakes, small- to medium-sized mammals, fruits, seed, spiders, other plant material, birds, reptiles, fish, eggs and carrion in their diet. Side-striped and golden jackals tolerate wetter and more densely vegetated habitats than the black-backed jackal, and are known to live on the fringes of human settlements and include human refuse in their diet (Atkinson & Loveridge, 2004: 153). They are also known to kill smaller predators like bateared foxes, mongooses and Cape foxes (Kamler et al., 2012, Kamler et al., 2013) presumably to reduce competition and as an opportunistic food source.
Unlike the side-striped jackal, the black-backed jackal tends to shy clear of human settlements. However, in Botswana there are indications that anthropogenic food sources such as rubbish dumps, domestic chickens, dogs and cats as well as refuse from fishing activities have become small but significant aspects of black-backed jackal diet (Kaunda & Skinner, 2003).
Black-backed jackals prefer relatively open habitats, a characteristic that suites their role as coursing predators (taking prey on the run) (Loveridge & Macdonald, 2003: 150). However, they are also ‘searchers’ (especially of young fawns hiding in the vegetation) and scavengers. Compared to the other jackal species, the black-backed jackal has a smaller molar grinding area and a larger pre-molar cutting blade, indicating that it evolved to specialise mostly on meat whereas the side-striped and golden jackals are more omnivorous, and are closer to the red fox (Vulpes vulpes) in this regard (van Valkenburgh, 1991: 343-4).
Whereas side-striped jackals are generally not known to be significant predators of livestock, black-backed jackals are a problem for farmers in many live-stock producing areas of South Africa (Loveridge & Macdonald, 2003: 144). Black-backed jackals kill sheep (mostly lambs) by strangulation (biting on the neck to seal the trachea) which is similar to how they kill wild ungulates (Rowe-Rowe, 1975: 79). In Botswana black-backed jackals have been observed hunting larger ungulates like impala (Aepyceros melampus) collectively on an opportunistic basis (McKenzie, 1990) and singly (Kamler et al., 2010). Do Linh San et al. (2009) found that one fifth of black-backed jackal diet in the Great Fish River Reserve (where there are no apex predators) comprised ungulate lambs and calves. Klare et al. recommend that black-backed jackals should be seen as members of the large carnivore guild given their capacity for hunting ungulates (2010: 1039).
Black-backed jackals are, however, also adept at scavenging carrion (Van de Ven et al., 2013) and are known to feed on carcasses around lions and spotted hyenas (Loveridge & Macdonald, 2002: 604). In Botswana, they may also have an association with particular prides, following them to scavenge on their kills (Smithers, 1971: 149). The importance of carrion in increasing black-backed jackal numbers was shown recently with the introduction (and then cessation) of a ‘vulture restaurant’ (the provision of dead cattle from farms) in the Mankwe Wildlife Reserve in the Northern Province. Black-backed jackal [and brown hyena] abundance increased after the introduction of the vulture supplementary feeding program, and declined after it was ended – whereas black-backed jackal numbers remained stable in nearby Pilansberg National Park where no vulture restaurants were provided (Yarnell et al., 2015). Ćirović et al. (2016) found that in Serbia, the golden jackal was important as a ‘cleaner’ of anthropogenic animal waste such as dead livestock and the remains of hunted animals. They argued that this, together with the fact that the golden jackal consumed large numbers of pest rodent species, implied that this mesopredator provided unacknowledged ‘ecosystem services’ for people in the area. They argued that as farmers in the area were not complaining about stock losses, any livestock consumed was almost certainly carrion.
In the first ‘natural history’ of the black-backed jackal, Fitzsimons assumed that it had evolved primarily as a scavenger but had subsequently become a specialist predator of colonial live-stock in South Africa as a consequence of the extirpation of large predators and migratory herds of game (Fitzsimons, 1919b: 97, 100). There is some support for this hypothesis in that scavenging opportunities from large ungulates killed by cheetahs were the predominant food source for black-backed jackals in the Samara game reserve (near Graaf Reinet in the Great Karoo, Eastern Cape) and this did not vary across seasons. However, Brassine & Parker (2012) found that black-backed jackals actively predated on ungulates, young and old, in game park areas of the Eastern Cape irrespective of whether larger carnivores (and hence scavenging opportunities) were evident. Yarnell et al. (2013) came to similar findings. This suggests that the balance between scavenging and active hunting varies according to context and that it is best not to draw conclusions about back-backed jackal dietary preferences in the abstract. A study of black-backed jackals on the Skeleton coast of Namibia revealed that they were unselective scavengers of dead fish, birds and penguins and actively hunted and killed seal pups (Avery et al., 1987), pointing once again to opportunistic hunting and scavenging behaviour.
A study of the diet of black-backed jackals and brown hyenas in the North-west Province (in protected areas and on farms) found significant overlap between the two species, but that the black-backed jackal was more likely to hunt its prey than the hyena (van der Merwe et al., 2009).
Black-backed jackal diet in the Namib Desert has been found to comprise mostly the giant longhorn beetle (Acanthophorus capensis) and locust (Anacridium moestum) with mammal remains found in only one third of the samples (Goldenberg et al., 2010). Insects were also the most common item found in a sample of black-backed jackal stomachs in Botswana, followed by small mammals and carrion (Smithers, 1971: 149-150). Such studies highlight how the diet of the black-backed jackal alters depending on locally abundant food sources. Their diet varies seasonally along with the prey base (Forbes, 2012).
A recent study of black-backed jackal diet before and after two management interventions in the Karoo National Park, namely the population reinforcement of springbok and then the reintroduction of lions, also reveals their dietary flexibility. After additional springbok had been released into the park, black-backed jackals consumed more springbok, but following the reintroduction of lions which produced scavenging opportunities on large ungulates, they consumed more large ungulate carrion and their relative consumption of springbok declined to pre-reinforcement levels (Fourie et al., 2016). The authors conclude that this highlights ‘just how contextdependent the diet of a small generalist predator is, with rapid and substantial shifts in diet as the resource-base shifts’ (2016: 8). In support of this conclusion is the findings from a nature reserve in Kwa-Zulu Natal, were black-backed jackals were found to be mostly ‘searchers’ (and pursuers and scavengers only opportunistically) and to utilise the most abundant, conveniently sized prey (Rowe-Rowe, 1983).
A study of black-backed jackals in the Cape Cross Seal Reserve on the Namib desert found that the Cape fur seal (Arctocephalus pusillus) was the main food item, followed by birds (mostly the cormorant) – the rest being ‘unidentified vertebrates’ (Hiscocks & Perrin, 1987). The study included direct observations of feeding and confirmed that most food was carrion with 36/37 cormorants eaten being scavenged (the other was a waterlogged bird) (ibid: 56). Blackbacked jackals were seen drinking from temporary rock pools caused by fog condensation, and licking condensed moisture off rocks in addition to scraping lichen off rocks to consume (loc cit). They attacked dying adult seals, and pups, but otherwise ate seal carcasses that washed up on the beach (ibid: 57).
Studies that link black-backed jackal diet to an index of prey abundance are able to determine whether jackals ‘prefer’ certain prey items, that is, if they consume a greater proportion of them than their relative availability in the landscape. Kamler et al. (2012b) found, using scat analysis, that on a sheep farm in the Free State, 25 to 48 percent of the biomass consumed by black-backed jackals was sheep (with consumption peaking in the lambing season) and that wild ungulates such as springbok and steenbok (Raphicerus campestris) comprised 8 to 47 percent of the biomass. Although sheep were the main food source, compared to the biomass available, black-backed jackals selectively consumed mammals of between 1 to 3 kilograms across all seasons and wild ungulates were selectively consumed over sheep in most seasons. Kok & Nel (2004) compared the dietary composition of black-backed jackals in the Free State with sympatric felids (caracal and African wild cat), finding that they had a much higher ratio of opportunistically caught prey (notably invertebrates) and that the capacity of the black-backed jackal to consume a wide variety of food sources allowed it to live sympatrically with other potentially competitive predators.
In short, the literature on black-backed jackal diet is strongly suggestive of great adaptability to local food sources and the presence of other predators. In a recent meta-analysis of dietary studies of black-backed jackals and golden jackals, Hayward et al. conclude that dietary preference appears to be shaped by ‘topdown’ factors such as the presence of large carnivores and ‘bottom-up’ factors such as prey size, abundance, behaviour and habitat. Their analysis of available data suggests that golden jackals have a consistent preference for hares, and black-backed jackals for small ungulates, mostly higher species such as springbok. However, their findings say as much (if not more) about the geographical location of the underlying studies as it does about what ‘the’ blackbacked or golden jackal prefers.14 We caution against making overly universalising claims about black-back jackal diet given how adaptive and flexible it has proved to be across different landscapes.
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