Aspects of the Ecology and the Behaviour of the Leopard Panthera pardus in the Kalahari Desert

1. What they did

Leopards in the Kalahari Desert leave clear tracks in the soft sand, so a whole night of hunting and travel can be read step by step. The authors followed leopard tracks in the northern Kalahari Gemsbok National Park, South Africa, between 1976 and 1983, in two habitats: the open dune sandveld of the interior and the camel-thorn woodland of the dry Nossob riverbed.

• Finding a trail. From a base camp the team searched for fresh leopard tracks. They told males from females by track size and by seeing the leopards.
• Following it. A tracker followed the tracks on foot, giving details of what was found to observers following closely in a vehicle. They recorded every activity of the leopard and the distances involved.
• Catching up. When the tracks showed they had caught up with the leopard, the team withdrew and returned early next morning to follow the previous night’s activity.
• Recording hunts. A “contact” was any reaction to prey: a stalk (approach in stalking posture of at least 10 m), a chase (a rush of at least 5 m), a kill, or a mix of these. Prey was grouped as small (up to springhare size), medium (bat-eared fox size up to, but not including, adult springbok size) and large (adult springbok and bigger).

New data covered male leopards in the interior (11 visits) and females with cubs in the Nossob riverbed (2 visits). Data for females with cubs in the interior came from the authors’ earlier paper (Bothma and Le Riche 1982), for comparison.

2. What they found

Prey and hunting

• In the interior, males contacted 14 prey types and females with cubs 15. Together, interior leopards contacted 19 prey types and killed 12. Porcupine, steenbok, aardvark and gemsbok calves were contacted most often.
• Medium-sized prey made up most contacts (64% for males, 50% for females with cubs). How often a prey type was killed matched how often it was met, so medium-sized prey were common in the diet because they were common, not because leopards preferred them. Porcupines may prove to be a preference with more data.
• Males made 2.8 contacts per day and females with cubs 2.9. Males killed 12% of prey contacted, females with cubs 23%. Males killed once every 3 days, females with cubs once every 1.5 days, and females with cubs in the Nossob riverbed once every 1.3 days.
• On the first night after a kill, males stalked much less, but chased just as often.
• Only 3% of male contacts were a full stalk, chase and kill. Of 20 kills by males, 65% involved no stalk or chase at all: prey were simply met and killed. Only 8% of 74 chases by males ended in a kill (28% for females with cubs). 68% of chases had no stalk before them.
• The aardvark and the steenbok were stalked far more often than they were killed. One male killed six times in 12 days, four of them porcupines ambushed as they left their burrows.
• In the Nossob riverbed, where springbok are plentiful, adult springbok were 56% of 16 known kills, and large prey were 69%.

Kills and feeding

• Only 2 of 30 kills in the interior kept a leopard at the carcass for more than a day (an aardvark for three days, a gemsbok calf for two). All prey except one adult red hartebeest cow (about 180 kg) weighed less than 70 kg. Other carnivores made up 30% of the 30 kills.
• Males ate an estimated 3.5 kg of meat per day, females with cubs 4.9 kg.
• Prey was dragged under a bush or tree for cover, on average 410 m by males (up to 4.9 km, a bat-eared fox carried before being eaten) and 742 m by females with cubs in the interior, but only 57 m in the Nossob riverbed.
• Kills were moved into trees only when scavengers disturbed the leopard: 7 of 38 kills (18%).

Movement and activity

• Males in the interior moved a mean of 14.3 km per day: 9.9 km on days with kills and 16.1 km on days without. The longer since the last kill, the farther they moved (20.9 km on the fourth night and later). The longest was 33.0 km in a day, ending in mating.
• Females with cubs moved 13.4 km per day in the interior but only 3.8 km in the Nossob riverbed, a significant difference.
• Leopards rested often near the start and end of each night’s travel, and seldom in the middle, when they seemed most intent on hunting.

Cover and water

• By day, males lay up under plant cover in 78% of 58 cases, mostly low, dense witgat trees, and otherwise in porcupine or aardvark burrows. Females with cubs used burrows in half of cases, and cubs often hid in aardvark burrows.
• Males drank only every few days, going up to 113.4 km and up to 10 days between known drinks. Females with cubs were never seen to drink.

Reproduction and other leopards

• All females followed had cubs. Young cubs (estimated under 3 months) were found in eight different months. Litters were 1 or 2 cubs (mean 1.5).
• Tracks showed that mating pairs stayed together for at most 24 hours, and that mating involved much chasing over a small area before copulation.
• An interior area of about 800 km² was used by two adult males and three females with cubs. No contact between leopards of the same sex was seen.

Scent marking

Besides ordinary urination, leopards squirted small amounts of urine on low shrubs and grass tufts (then raked with the hind feet), backwards onto the low branches of shrubs, especially witgat, and onto tree trunks. They also rolled where other animals had urinated or defecated, raked tree trunks with their front claws, and rubbed against trunks.

Other carnivores

Black-backed jackals and brown hyaenas sometimes followed leopard tracks to scavenge, and jackals were sometimes killed as a result. A spotted hyaena once drove a female from her kill, but larger males twice defended kills against two spotted hyaenas. Two lions once took a large male’s prey.

3. What they concluded

• Kalahari leopards are opportunists that will try to kill almost any prey. What they kill depends mostly on what is available in each habitat, though individual leopards develop their own tastes.
• Because they mostly kill medium-sized prey that are eaten quickly, and scavengers are scarce, they seldom store kills in trees.
• They rarely use the full stalk, chase and kill sequence. Stalking matters less than elsewhere, and chases in the open are longer than reported for East African leopards. Their hunting success shows leopards can hunt efficiently in open country.
• They kill more often than leopards elsewhere, yet return to the same general area only every 4 to 6 days, which may give prey time to settle.
• Their ranges are far larger than reported anywhere else, with about one leopard per 160 km², which probably reflects scarce food.
• Lions dominate leopards, and the two seem to be separated by prey size. Encounters with spotted hyaenas depend on the leopard’s size and the number of hyaenas.
• Leopards do not depend on drinking water, and females seem to have no fixed breeding season.
• Long daily movements and opportunistic hunting let leopards live successfully in this harsh desert.

4. How tracking was or was not used

Tracking was the main method. The team found fresh leopard tracks in the sand and followed (trailed) each leopard’s route of the previous night on foot, often for complete 24-hour periods, until they caught up with the animal. From the tracks they read stalks, chases and their distances, kills, drag marks and drag distances, feeding, storage of prey in trees, resting places, daytime lie-ups in vegetation and burrows, drinking, urine marking, scrapes, rolling, tree scratching, mating and encounters with other carnivores. Leopards were sexed by track size and by sight.

5. Tracker or observer certification

Not reported. A tracker led on foot, but the paper says nothing about the trackers’ skills or how they were tested, although all the findings rest on reading tracks. The acknowledgements say various trackers were used, especially Frans van Wyk, Riekie Kruiper, Jan van Rooi (Tsipan) and Albertus Bojane (Magistraat), who made substantial contributions.

7. Implications for conservation (from the paper)

• Leopards in the Kalahari live at low density (about one per 160 km², compared with one per 29 km² in Kruger National Park) and range over very large areas.
• Extensive movements in the interior spread their hunting pressure, so no single area is hunted heavily.