Sunday, 18 October 2020

Small Cats: Servals in the Savannah, Cats in the Congo

The best-known wild cats living in Africa are, of course, the large ones: lions, leopards, and cheetahs. South of the Sahara, they are joined by two species of small cat: the African wildcat (from which the domestic animal is descended) and the black-footed cat, both of which I have already described in this series. To these, we can add the caracal, a medium-sized cat that closely resembles the lynxes of Eurasia and North America. But, although this was most likely the animal that the word 'lynx' was originally coined to describe, the caracal is not closely related to what we would now regard as the 'true' lynxes. Instead, it is part of a distinctively African lineage of similarly medium-sized cats, containing just two other living species.

The more familiar of the two is surely the serval (Leptailurus serval), an animal that is not only widespread across Africa, but that happens to be relatively easy to breed in zoos. The name apparently derives from an alternative (and now obsolete) Portuguese name for the lynx that has now replaced variants of the older English name of "tiger cat" in most non-African languages. (It's still tierboskat - literally "tiger-forest-cat" - in Afrikaans, and, unsurprisingly, languages such as Swahili had perfectly good words for it already).

Honestly, though, it doesn't look much like a tiger. Servals are typically spotted like a cheetah, although some all-black individuals are known, mostly from Ethiopia. Their body form is, however, distinctive for a cat. They are about the same weight as ocelots are, ranging from 7 to 13 kg (15 to 29 lbs) but are much taller, standing up to 60 cm (2 feet) tall at the shoulder due to their longer legs. While the tail is relatively short, their ears are large even by the standards of cats and their sense of hearing is exceptional.

In the wild, servals live across almost the whole of the sub-Saharan Africa, except for the jungles and the dry regions around the Kalahari Desert. The preferred habitat of servals is savannah wetlands, although they can be found in both semi-desert and denser forest margins. In the former case, they rarely stray far from the few rivers that penetrate into such regions. The recent expansion of irrigated farmland in central Namibia may therefore explain why they seem to be becoming more common in that region in the last few years, even as they have largely been driven away by competition with farmers in the Cape region of South Africa.

Despite their size, servals primarily feed on small rodents, such as rats and gerbils, which can form around 80% of their diet. They will also eat small birds, lizards and so on, and do take the occasional larger animal, such as hares, flamingos, or even young antelope. Their reliance in wetlands is not so much due to a need for water directly (although that presumably helps) but on the fact that they hunt in reeds and long grasses, using their long legs to gain a high vantage point. Unlike most other cats, however, they hunt almost entirely by sound, often remaining motionless for up to 15 minutes at a time to listen out for any rustling in the vegetation, and avoiding hunting altogether on windy days when there is too much noise.

Once they have located prey, they leap on it in a sudden pounce and, like caracals, they are even capable of catching birds on the wing by leaping into the air. A single leap can reach over 3.5 metres (11 feet) horizontally or 2 metres (6 feet) in height and is often all they need to dispatch their prey. Otherwise, they can use their curved claws and slender limbs to hook animals out of shallow burrows or from under dense vegetation or make a series of shorter hops to catch something that manages to survive the initial assault.

Servals are naturally crepuscular but switch to a nocturnal lifestyle where humans are more abundant. They use the tall grass or reeds to hide in when they sleep, although some have been reported to use abandoned aardvark burrows or other ready-made shelter. Like other cats, they are typically solitary, each, occupying patches of land that they scent mark with urine spraying and by leaving their droppings uncovered (again, unlike many other cats). They can remain in the same area for years at a time and, as might be expected, there is considerable overlap between the ranges of males and females, but not between animals of the same sex.

Servals are able to breed throughout the year but typically mate shortly before whatever the breeding season is for the local rodents, ensuring plenty of food for the kittens. Litters contain up to four kittens, although two is more usual, and the young remain with the mother for about a year before striking out on their own. Surprisingly, given their genetic distance, servals are able to crossbreed with domestic cats. In part because they both have 38 chromosomes, the results are fertile; they are also among the largest of all domestic cat breeds (if you can call a hybrid a "breed") and appear even larger because of the long legs.

African golden cat

The closest relative of the caracal, however, is not the serval, but the African golden cat (Caracal aurata). Formerly placed in its own genus, Profelis, it diverged from caracals only during the Ice Ages, sufficiently recently that it's now more commonly placed alongside them.

Far less is known about this than either of its cousins, and it's one of the world's more obscure cat species. Partly that's because it's less common than other African cats and avoids humans, but there's also the factor that it's the only one to inhabit damp, tropical forests - where the undergrowth can be so dense it's difficult to spot. Indeed, while there are reports of sightings from Kenya, which it has presumably reached by following strips of dense woodland along major rivers, it's otherwise only found in the jungles of west and central Africa, from southern Senegal to northern Angola. 

Physically, it's another medium-sized cat, with a similar body weight to the serval, but without the long legs. However, males are much larger than females, weighing around twice as much - 14 kg (31 lbs) compared with 7 kg (15 lbs). They have sturdy bodies, with moderately long tails, and smaller ears than either the serval or caracal. Their coat colour is also variable, often being the golden hue that its name would suggest, but sometimes much greyer or even solid black, and sometimes with spots and sometimes without. The grey and golden forms were once thought to be separate species, but, while two subspecies are now recognised, with the central African one more often having the spotted coat, the background colour just seems to be individual variation.

The few studies on the diet of golden cats show them to prey on a wider range of animals than either of their kin. They certainly do eat rats, mice, shrews, and so on, but they also take larger animals such as monkeys, a kind of small antelope called a duiker, and even porcupines and pangolins. Although they are reasonably competent at climbing trees and do take the odd squirrel, most of their prey is ground-dwelling, so they likely do much of their hunting among the dense jungle undergrowth.

Most reports seem to suggest they are nocturnal, or at least crepuscular, but even that isn't clear. There is literally one scientific report of a wild mother with a kitten, which she was raising in a hollow log, although a captive pair were successfully bred a few times in the 1970s, producing litters of two kittens on each occasion. And that pretty much sums up everything we know about this elusive cat.

It also brings me almost to the end of my survey of the smaller cats of the world. There's just one branch of the family tree left to look at, and to find that, we will have to head to the jungles of Southeast Asia...

[Photo by Lee Elvin, from Wikimedia Commons. Illustration by John Gerrard Keulemans, in the public domain.]

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