A lioness pilfers the remains of a leopard’s kill, Ngala Game Reserve, South Africa. Lions are not nearly as well equipped as leopards for scaling trees, but as illustrated here, they are quite capable climbers. Fortunately for leopards, lions are too heavy to reach the smaller, outer branches where this leopard found refuge.
Although similar in size and weight, the leopard’s heavier build and greater muscularity means they easily dominate cheetahs; here, a leopard chases two cheetahs in the Sabi Sabi Game Reserve, South Africa. On rare occasions, mother cheetahs with young cubs stand their ground against leopards, but typically only enough to provide a diversion for the cubs to reach safety.
Africa is exceptionally rich in carnivores. Excluding the unique carnivores occurring on Madagascar, there are some 75–77 species in Africa (taxonomic uncertainty among some smaller carnivores clouds the issue slightly). This is not the highest continental tally, but nowhere else compares for sheer numbers. Measured in biomass, there are more carnivores per square kilometre in Africa than anywhere else. Mostly, this is due to the rich productivity of the savannas. With bountiful vegetation supporting herbivores of all sizes at high densities, carnivores reach their highest numbers in savanna woodlands, and interactions between carnivores are probably more common there than in any other habitat. In less productive areas, carnivores are less abundant and interactions between them are thought to be less common (or perhaps just less easily observed) but the relationships remain similar. Except for the remote interior of the Sahara where only the highly specialised sand cat exists, there are no large, natural areas in Africa where any cat species lives in isolation from others. Confrontations between different felids are typically hostile in a hierarchy that is essentially linear; predictably, larger species dominate smaller ones in their day-to-day encounters.
As the largest carnivore on the continent, the lion has little to fear from other cats except for occasional losses of young cubs. George Schaller describes an incident in which a Serengeti lioness left a very young cub at her kill, despite knowing that a leopard was resting in a tree directly over the carcass. As the lioness departed to fetch her other cub, the leopard quickly descended the tree and killed the cub left behind. Such incidents occur from time to time, but the leopard is the only recorded feline predator of lion cubs. While adult cheetahs, caracals and perhaps even servals and African wildcats are plausibly capable of killing young lion cubs left unattended, losses to these species must happen extremely rarely, if at all. With the occasional exception of young cubs, the lion is essentially invulnerable to any feline threat other than that from strange conspecifics (see Chapter 4).
On the other hand, the lion is an important threat to all other cats, irrespective of age. As discussed in the previous chapter, they represent the main source of mortality to cubs in well-studied populations of cheetahs and leopards, but if given a chance, lions readily kill adult cats as well. Vulnerability to lion attacks appears to vary with habitat. In open habitats where cheetah cubs are most at risk, adult cheetahs have the advantage of visibility, space and their remarkable acceleration. Cheetahs can spot danger coming from a distance and have few obstacles to negotiate in fleeing, so it is rare for a healthy adult to be killed by lions in such habitat By contrast, woodland habitats increase the risks for adult cheetahs. Ironically, despite the advantages afforded to mothers that raise their cubs in dense bush (see Chapter 4), single females and males are more likely to die here in clashes with other big cats. The cause of the disparity is unclear but is likely due to the mother’s heightened vigilance while raising a litter; mothers successfully counter the diminished visibility and fewer escape routes inherent in dense habitat by being more watchful. Females on their own and adult males, both of which, presumably, are less vigilant than mothers, suffer an increased chance of attack. During a five-year study where I monitored the large cats living in the dense acacia woodlands of northern KwaZulu-Natal, attacks by other cats (mainly lions and, secondarily, leopards) were the leading cause of mortality for adult cheetahs.
Kleptoparasitism
Aside from lethal confrontations, cats also impact one another through kleptoparasitism – securing an easy feed by displacing a sub-dominant species from its kill. Unsurprisingly, the chain of command is rarely anything other than linear: lions chase leopards and cheetahs from their kills, leopards displace cheetahs, and so on. The cheetah is worst affected, though not as severely as often depicted; of 325 kills made by cheetahs at the Phinda Game Reserve, only three were lost to lions and leopards (and only five kills in total were lost when all predators were counted). The widespread availability of cover at Phinda probably reduced losses for cheetahs, but even in open habitats, losses are fairly modest. During Tim Caro’s study of male cheetahs on the Serengeti plains, 14 of 110 kills were lost to kleptoparasites, considerably more losses than at Phinda, but the Serengeti cheetahs had usually fed substantially by the time they were driven off; Caro calculated that only around nine per cent of the meat caught by cheetahs was abandoned to thieves. Notably, none of the Serengeti cheetahs’ losses was to other cats; all were stolen by the spotted hyaena which, for most African cats, represents a greater competitive nuisance than other felids.
Intriguingly, the relationship between habitat and the lion threat swings the other way for leopards. Leopards easily evade lions by climbing the nearest large tree; in dense habitat, the options are legion and adult leopards in good health are rarely caught by lions. In open habitat, however, refuges are fewer and leopards do not have the cheetah’s advantage of speed; lions are faster than leopards on open ground. I once saw two lionesses come upon a male leopard resting in a large clearing in open terminalia woodland. The three cats simultaneously exploded into action, the leopard bolting for a large umbrella-thorn tree about 35 metres away with the lionesses on his tail. Despite a 10-metre starting advantage over the lionesses, by the time the leopard reached safety, they were less than a metre behind him. Only his extraordinary agility in scaling the tree saved him. In northern Namibia where large trees are more thinly spread, Phillip Stander recorded a female leopard killed by lions after taking refuge in a small tree that did not provide sufficient protection. Similarly, the wildlife photographer and naturalist Jonathan Scott photographed a young male leopard in Kenya killed by lions after being disturbed by tourists; the leopard fled the safety of cover and was caught by the lions on open ground.
Leopards, in turn, are capable of killing all cats (except, of course, lions other than young cubs) and the anti-predator benefits enjoyed by cheetahs in open habitats appear to wane in the face of the leopard’s more catholic tastes and exceptional stealth. In arid and open habitats such as the Kalahari Desert and north-eastern Namibia’s Bushmanland, leopards occasionally hunt cheetahs for food; carcasses of adult cheetahs are cached in typical leopard fashion and consumed in the same way as their regular prey items. Similarly, cheetahs (as well as caracals and servals) were recorded as prey in the Chipangali region of eastern Zambia shortly after a tsetse fly control programme had denuded the area of antelope prey. In more profitable habitats like the mesic savannas of eastern South Africa, leopards also kill cheetahs and other cats from time to time but seem less inclined to eat them, presumably because they have a greater choice. Their preferred antelope prey is abundant and they do not have to work quite so hard to secure a meal.
Gaining the advantage: interference competition
A pair of lionesses rushes in to claim the scavenged carcass of a warthog, northern Botswana. Outweighing the next largest felid species by a factor of two, a single lioness is more than a match for all other species of African cats.
Lions are capable of explosive bursts of speed and, over short distances, are able to out-run all other cats except the cheetah.
It begs the question, why do cats kill one another if not for food? Biologists usually cite three principal reasons: occasionally, they prey upon one another as food; secondly, they consider other cats as potential enemies of their offspring, so killing another cat removes a threat; and finally, they compete for the same resources. It is this last factor – specifically, ‘interference competition’ – that is widely considered to be the primary cause of conflict between felids, and also gives rise to clashes over carcasses (see text box ‘Kleptoparasitism’, page 133). Chris Carbonne and John Gittleman calculated that it takes 10 000 kilograms of prey to support 90 kilograms of predator; in other words, it requires about 475 rock hyraxes to support a caracal, 100 impalas to support a female leopard and 67 wildebeest to support a lioness. The relationship holds for carnivore communities around the world and it places a threshold on the total biomass of predators that can be sustained by an ecosystem.
Even so, this does not satisfactorily explain why some cats go to such lengths to kill other members of the family. As the most aggressive culprit, the lion is a puzzling case in point. As we have seen, lions rarely eat leopards or cheetahs they have killed, and lion cubs are seldom killed by other felids. This leaves competition for resources as the lion’s motivation, which seems reasonable, though it is unlikely that competition with any other felid affects lion survival or numbers. As discussed earlier, lions rely on large prey that is mostly inaccessible to leopards and cheetahs which, in turn, take smaller prey that comprises a minor proportion of lion diet. Indeed, such partitioning of prey is partly the reason cheetahs and leopards can exist alongside lions. Similarly, even though leopards and cheetahs share a similar diet, leopards subsist on a wider range of prey, and cheetahs naturally occur at low densities, such that any effect on leopards is likely to be negligible.
Interference competition might carry advantages in sub-optimal habitats where the struggle to secure prey is elevated and fewer options result in a greater dietary overlap among cats. Conceivably, the springbok-hunting lions in Etosha National Park would need to cover less ground or be forced to abandon fewer cubs in the search for prey if there were no leopards or cheetahs feeding off the same prey base, though no-one yet has successfully investigated the idea (see the following section for the effect when lions are removed). Elsewhere, perhaps like predators around the world, large cats exert dominion over smaller ones simply because killing is hard-wired, regardless of the quarry. It might also reflect a period in felid evolution when the number of carnivorous competitors was twice that of today (see Chapter 1) and removing other cats carried a direct benefit. Inter-specific aggression may persist today, not because it yields rewards but simply because it carries no significant costs.
In the final analysis, competition among cats likely has more to do with maintaining an advantage, but over evolutionary time rather than from one day to the next. Competition can produce significant effects on the sub-dominant species that may include changes in behaviour, numbers and distribution. Even when such effects are subtle, competition benefits the dominant species by keeping other cats in their evolutionary place. Given unchanging availability of resources, the competitive dominance of the lion ensures that leopards or cheetahs do not evolve larger body size and encroach upon the lion niche. Equally, although manifested very differently, the ability of small-bodied felids to exploit small prey better than large cats are able to, means the opposite does not happen. Although a leopard easily kills a serval, the serval out-competes any leopard as a rodent hunter; the leopard cannot evolve into a rodent specialist while servals (and other small felids) continue to occupy that niche so successfully.
Large Nile crocodiles like this individual are formidable foes and are mostly safe from lions provided they are not caught on land, where lions have the advantage. There are reliable records of lions killing crocodiles as large as three metres.
The effect of competition and conflict
On average, the likelihood that this leopard cub will survive its first year is around 50 per cent. In the more marginal habitat of the Kalahari, survival of cubs is estimated at around only 10 per cent.
As the most arboreal of big cats, the leopard’s ability to find refuge in trees is a key factor in its ability to reach high densities where lions and spotted hyaenas are abundant.
How do the complex interactions between cats affect one another in the long term? Every indication is that the loss of cubs or kittens is an extremely stressful event for a mother cat. Yet female cats recover quickly and are able to reproduce again rapidly following the death of a litter (see Chapter 4), so it may constitute no more than a temporary setback for an individual. Similarly, the killing of an individual by another cat may have little effect on a population, or indeed on the species.
For most populations of felids, the effect of interference competition from other cats is probably minor. As biologist Phillip Stander has noted of leopards, the cat’s ability to conceal itself and its food means that adults generally suffer little from inter-specific predation and competition. Yet even for the versatile leopard, predation by lions is the primary threat to cubs in areas where the two species coexist (see Chapter 4). How can biologists conclude that interference from lions is having little effect on leopard populations when up to half of their cubs are killed by the larger cat?
Freed of predation by lions, more leopard cubs would survive. Imagine Kruger National Park suddenly devoid of lions: leopards would find themselves in an environment without the major killers of their offspring, therefore many more leopard cubs would survive. Perhaps – yet even with lions present, leopards in Kruger reach the highest densities recorded for the species: up to 30 adults and independent sub-adults for every 100 square kilometres in the productive southern region of the park, an area where lion densities are also extremely high. The leopard density in Kruger is probably at capacity; even if lions were absent, leopards could not reach greater numbers. As ecologists would define it, the leopard population is regulated by ‘density-dependent’ processes; as leopard density climbs, space becomes scarce, conflict increases among leopards and fewer young leopards survive to be absorbed into the population. If density declines (for example, following drought or a disease episode), a greater percentage of young leopards survive to fill the newly opened spaces until capacity is reached again. Ultimately (as described in Chapter 3), the ceiling is established by the availability of resources, not by how many lions are around or how many leopard cubs they kill.
In other words, even a high level of lion predation on leopard cubs is primarily compensatory rather than additive to the overall mortality rate. Lions remove a percentage of leopards that cannot be recruited into the population anyway. So, while the absence of lions might elevate cub survival, an inevitable balancing effect would be felt somewhere else in the population; perhaps more sub-adults would die during dispersal, or the territorial tenure of adults would be truncated by a larger sub-adult cohort competing for space. In theory, the effects of lions might be more extreme in small populations of leopards, those in sub-optimal habitat, or in concert with aggravating factors like drought or reduced prey availability; but so far, there are no rigorous studies demonstrating such an effect.
Density-dependent processes probably contribute to the population dynamics of most felids, but this is not to say that interference competition from other cats never has an influence. Indeed, under certain circumstances, the effect may be profound, such as those arising from the exceptionally high losses of cheetah cubs to lions in the Serengeti (see Chapter 4). In contrast to the negligible impact of lions on leopards, their impact on the population dynamics of Serengeti cheetahs is very marked. More than 25 years of continuous monitoring by Sarah Durant, Tim Caro and colleagues has revealed that the lifetime reproductive success of female cheetahs on the plains is significantly related to the presence of lions. Further, as lion numbers rise, cheetahs have a harder time raising cubs. From the late 1960s, lion density in the Serengeti has climbed (probably due to increases in wildebeest numbers following rinderpest control operations) with a corresponding decline in the reproductive success of female cheetahs. Comparing two time periods – 1969–1979, when lion density was low, and 1980–1994, when lions were more numerous – cheetah litters at emergence declined from an average of 2.9 cubs to 2.1 cubs, and average litter size at independence declined from 2.5 to 2.0 cubs. On average, a female raised 2.1 cubs to independence in the 1970s compared to only 1.6 cubs more recently.
Although these declines may seem modest, they are significant enough to push the population across the threshold of viability. Given that the cheetah population always contains fewer adult males than females, and that the survival of only a small number of male cubs is required to replace males that die, an adult female has to replace only herself for a population to remain stable. In other words, she needs to raise just one female cub in her life (assuming the odd female also raises a male cub) – but that cub must also reproduce to avert a decline. Given the losses occurring after independence and the fact that half of all cubs at independence are male, even successfully bringing 1.6 cubs to independence is not sufficient. As cat biologist Marcella Kelly puts it, the cheetah population on Serengeti’s short-grass plains was already ‘failing’ by 1994, largely due to pressure from lions.
Escaping competition
Cheetahs are nervous feeders, particularly when faced with a lack of cover, as with this family on a Thomson’s gazelle kill in Kenya’s Masai Mara National Reserve. Exposed like this, cheetahs scan their surroundings constantly for possible threats and sometimes abandon the carcass when the inevitable build-up of vultures increases the chance they will be discovered by lions.
The effects on cheetahs can be seen elsewhere by examining the outcomes from a different approach – where lions are extinct. In areas where persecution by people has wiped out lions, cheetahs prosper (see text box ‘Predator release’). On Namibian ranches, the average litter size numbers 3.2 cubs at emergence and 2.4 cubs at independence. More dramatically, mortality of Namibian cheetah cubs in the first year is around just 25 per cent (this excludes losses in the den, but predation on young Namibian cubs is thought to be rare because there are no lions or spotted hyaenas). Ironically, the gains enjoyed by cheetahs in Namibia are threatened by conflict with people (see Chapter 6), but even so, Namibia has the largest contiguous cheetah population anywhere, due, in considerable part, to the absence of lions (and, to a lesser extent, of spotted hyaenas) in most of the country.
‘Predator release’, or liberation from predators, probably benefits other African cats at times, although, for the most part, it has not been accurately assessed. Paradoxically, it may apply to the least studied felid on the continent, the African golden cat. In most of their range, golden cats co-occur only with the larger leopard, and the overlap in their respective diets can be acute. In the Central African Republic’s Dzanga-Sangha Reserve, 92 per cent of prey species are common to both cats, particularly the 4.5 kilogram blue duiker. Furthermore, golden cats are occasionally killed by leopards. Philipp Henschel found golden cat remains in five leopard scats from a sample of 197 collected in Lopé, Gabon. The little known about the golden cat suggests it thrives when its larger cousin is removed. In equatorial Africa, Henschel’s work has revealed that leopards are easily extirpated from secondary forest, areas that have been logged and subsequently clogged with thick, moist regrowth. Leopards do not tolerate the human activity that creates secondary forest (see Chapter 6), which also ranks as poor habitat for larger leopard prey such as forest duikers. However, secondary forest is prime habitat for small rodents and ground-dwelling birds, the perfect prey for golden cats. The absence of leopards combined with elevated densities of small prey is a likely recipe for a predator release scenario that benefits the golden cat. Although hard data are mostly lacking, the extinction of the leopard in Uganda’s Bwindi Impenetrable National Park has promoted the golden cat to the role of top predator and these cats are thought now to be the park’s most common felid.
Where it occurs, predator release results primarily from the activities of people. In natural systems, it probably occurs from time to time – for example, the 1994 distemper epidemic among Serengeti lions (see Chapter 4) might provide temporary respite for cheetahs – but for the most part, different cats manage to coexist regardless. As we have already seen, the risk of being killed or having a carcass stolen by another cat is actually quite low, chiefly because most cats excel at avoiding conflict with their larger relatives.
Although populations of all species are influenced by a host of factors – one of which may be predation – the removal of a predator or dominant competitor from an ecosystem often produces profound effects in lower order species. Altered activity patterns, changes in foraging or vigilance behaviour and, especially, rapid increases in numbers are indicative of predator release: liberated from its predator, the prey species flourishes. Among carnivores, there is now considerable evidence for mesopredator (meaning ‘middle predator’) release; when the dominant carnivore is removed, mesopredators benefit from a reduction in predation, kleptoparasitism or competition for prey. Most long-term studies come from the northern hemisphere, for example, the proliferation of coyotes in the United States following the widespread extirpation of wolves; but the pattern doubtless also holds true for African carnivores. Within the cat family, mesopredator release applies to cheetahs in areas lacking lions and spotted hyaenas, and perhaps also benefits African golden cats where leopards have been extirpated (see main text).
The coexistence of similarly-sized caracals and servals is a compelling example of segregation. Caracals (ABOVE) focus on larger prey in broken, drier habitat and are largely crepuscular and nocturnal; by contrast, servals (BELOW) concentrate on small rodents in well-watered, open habitat and are mostly crepuscular or diurnal.
Cheetahs are active mainly during the day, in part to maximise visibility during high-speed chases but also to avoid lions and spotted hyaenas. Females with young cubs are particularly careful about drawing the attention of larger carnivores and often hunt during the hottest part of the day when other predators are inactive.
They achieve this by the ecological mechanism known as segregation: temporal (in time), spatial (in space) and dietary (in food). In other words, overlapping species reduce conflict by being active at different times, in different places and by eating different prey. Cheetahs hunt during the day, in part because lions are then inactive and unlikely to notice them. Counterintuitively, cheetahs also avoid prime areas with high densities of prey, because such congregations also attract lions and spotted hyaenas. Leopards occur wherever lions are found and both hunt primarily at night, but leopards select smaller prey and better exploit certain features of the environment than lions – well vegetated areas such as river valleys and thickets, and trees in which they cache kills, neither of which is easily accessible to lions. Similarly-sized servals and caracals are able to coexist because servals specialise in rodents while caracals have a greater reliance on larger mammals; both species eat both types of prey, but limit direct competition by reducing the overlap. They further reduce competition by selecting different habitats in the same area: radio tracking of caracals concurrently with servals in South Africa’s Drakensberg mountains showed only a 20 per cent overlap in the area used by both species, with servals preferring low-lying, well-watered areas and caracals dominating higher rocky, dry ground.
In conclusion, it is important to note that while segregation promotes coexistence, it is the flip side of the same relationship that imposes changes in behaviour, density and distribution that, sometimes, are less than ideal. Cheetahs manage to persist in the Serengeti but are forced to avoid the best areas in order to steer clear of lions, and clearly would be better off without lions. Similarly, golden cats will not disappear from African rainforests because of the presence of leopards but, in the absence of leopards, golden cats might be at an advantage. So even where many species of felids coexist and overt interference competition between them is slight, cats may exert an indirect, subtle but profound influence on one another. These intricate relationships between different felids have existed for millions of years, yet we are only now starting to unravel their complexity.
Relationships with other carnivores
Lionesses finish the remains of a kill as spotted hyaenas and a black-backed jackal wait in attendance, Savute, Botswana; in this case, the hyaenas made the kill – an adult warthog – but the lions usurped it. The hyaena is an adaptable, highly successful predator that reaches high densities in conservation areas but is heavily persecuted on unprotected land.
One on one, female leopards are usually subordinate to adult spotted hyaenas. Hyaenas are larger and equipped with a bite force at the carnassials over 40 per cent more powerful, so leopards generally give way, as pictured here – this female leopard relinquished her bushbuck kill rather than fight. Adult male leopards are powerful enough to present more of a competitive challenge and more often stand their ground or, occasionally, kill single hyaenas.
A female cheetah pauses to wait for her two young cubs, Masai Mara National Reserve, Kenya. As her cubs approach, she gives chase to a potential menace, a black-backed jackal. Cheetahs, particularly hungry sub-adults, sometimes kill jackals for food but adult cheetahs mostly ignore them except when they are perceived as a threat to their cubs or kills.
As we would expect, the same complex patterns apply to the interactions of cats with other carnivores. Next to lions, the spotted hyaena is the dominant predator in African ecosystems, and it is a superior competitor, as well as a direct threat, to most cats. Long held to be a cowardly skulker that subsists by scavenging the remains of lion kills, spotted hyaenas are efficient and extremely powerful hunters in their own right. Indeed, by hunting in groups, spotted hyaenas take prey considerably larger than themselves and usually focus on the most abundant large and medium-sized herbivores available: wildebeest, gemsbok and springbok in the southern Kalahari, wildebeest and zebras in the Serengeti, and zebras and impala in Botswana’s Chobe National Park. This places them directly at odds with lions which concentrate on precisely the same prey. Competition between the two species is usually manifested in fierce, sometimes fatal, clashes over carcasses, but the relationship is not as one-sided as expected.
In numbers, the spotted hyaena is a dogged and daring competitor. Even though this lioness could easily kill a single hyaena, she is no match for the concerted harassment of a clan and she eventually yielded to them in this encounter. When male lions are present, hyaenas are far less likely to prevail.
Hyaenas weigh about half as much as a lioness and are not nearly as well armed to defend themselves. If caught, this hyaena will probably incur a savage mauling but lone lionesses are unlikely to press home a lethal attack if other hyaenas are present.
One on one, a lion easily kills even the largest, most aggressive spotted hyaena. However, by living in large groups, hyaenas are able to shift the balance and compete successfully with the much larger cat. The outcome of these clashes is dependent on two factors: the numbers of hyaenas involved and the presence of male lions. Almost regardless of their numbers, spotted hyaenas keep a respectful distance from adult male lions. In the absence of males, hyaenas are much more likely to prevail, but success also depends on the ratio of hyaenas to lions. In the Ngorongoro Crater, it takes an average of seven hyaenas to put one lioness to flight, while in Chobe National Park, the ratio is only four to one. Depending on the numbers a clan can muster, hyaenas may yield to lions one day and triumph the next.
The upshot of this is that lions and hyaenas appear to have little, if any, influence on each other’s numbers. Researcher Netty Purchase looked at the densities of both species across 13 protected areas in Africa and found a positive relationship; where there were more lions, there were more hyaenas. Despite their dietary overlap, hyaenas and lions reduce direct competition by targeting different segments of the prey population – juvenile ungulates are more important to hyaenas, whereas lions kill more adults. Further, lions exploit very large quarry mostly beyond the reach of hyaenas (such as adult buffaloes and giraffes), while hyaenas are better equipped than lions to track migratory prey. Depending on the balance of these factors at a site, lions sometimes outnumber hyaenas while the reverse holds true in another area.
The relationship of the hyaena to other cats is not as well understood, though in general they dominate other felids. As previously discussed, they sometimes kill cheetah cubs, and can drive adults from their kills; their overall effect on cheetahs seems moderate, although they likely exacerbate the problems faced by cheetahs in areas of high lion density. Similarly, they are able to dominate leopards, but single hyaenas are vulnerable to adult males; at least two hyaenas were killed and eaten by a large male leopard during Ted Bailey’s study. Further, leopards probably suffer less than cheetahs from hyaena kleptoparasites by hauling their kills up trees (although no-one has actually quantified the degree of loss that leopards sustain anywhere). Hyaenas surely kill the occasional smaller cat or drive them from their kills, but such events are unlikely to occur often enough to make a major impact. Small cats attract less attention, easily flee into trees and make small kills that are quickly consumed; so, for the most part, they are probably not worth more than opportunistic, cursory attention from hyaenas. Aadje Geertsema saw servals stand up to lone hyaenas in Ngorongoro Crater, including one occasion where a young male serval confronted an adult hyaena over the scavenged carcass of a juvenile hippo. Similarly, the wildlife filmmakers Owen Newman and Amanda Barrett secured a marvellous sequence of a mother caracal standing her ground against three hyaenas threatening her kittens. The hyaenas eventually made off with the caracal’s kill (a white stork) but the kittens survived.
In terms of their relationship with cats, African wild dogs occupy a position in the predator hierarchy which is very similar to that of cheetahs. Rosie Woodroffe and colleagues compiled the known causes of death to wild dogs across the five sites in Africa where the species has been most intensively studied, and found that lions comprise the single greatest natural threat to wild dogs, both adults and pups. Predation by lions comprised up to 47 per cent of adult deaths and averaged 10 per cent of mortality across all sites. Pup mortality attributed to lion predation was highest in Kruger National Park (37 per cent), and averaged 20 per cent of all pup mortalities across the five sites. Just as with cheetahs, where there are many lions, there are few wild dogs; and wild dogs go out of their way to avoid lions, even when that means forsaking the best areas. Gus Mills discovered that wild dogs in Kruger avoid areas of high impala densities because the same areas are preferred by lions (and spotted hyaenas, whose effect on wild dogs is similar, but probably more severe than their effect on cheetahs, at least in open habitats). In much the same way that lions are a principal factor in determining the distribution, numbers and behaviour of Serengeti cheetahs, so too do they influence the wild dog. The key difference, perhaps, is that wild dogs are affected throughout their range. Primarily a species of the woodland savannas, the wild dog overlaps extensively with lions and the negative relationship appears to hold true throughout Africa’s large conservation areas.
Finally, there is a suite of mesopredators that interact with cats, though their relationships are poorly known. Ethiopian wolves, brown hyaenas, striped hyaenas and three species of jackals (black-backed, side-striped and golden) co-occur with at least one felid species and, except for the wolf (which coexists only with servals), each is killed by or kills cats – but very rarely. Both species of hyaenas and all the jackals benefit from the carcasses left by large cats; so, despite having to keep a respectful distance and, occasionally, getting killed by a large felid, the net result for these species is positive. For cats, the relationship overall is probably neutral. We would expect equally-sized species to compete more intensively and indeed, given a chance, black-backed jackals harass caracals, but at their own risk. Karoo specialist Rob Davies saw two black-backed jackals tree a caracal, which subsequently leapt down and killed one of its tormentors. Some authors have speculated that the intense effort to wipe out black-backed jackals from parts of southern Africa has led to an expanded range and greater numbers of caracals (possibly a case of mesopredator release; see text box ‘Predator release’, page 141), but the theory remains untested.