28 September 2023
By: Fredalette Uys
The list of problem animals for sheep farmers in central South Africa now includes warthogs, which eat newborn lambs and even teach their piglets to do the same.
Warning: This report contains information and photos that may disturb sensitive readers.
Warthogs are an additional problem animal that sheep farmers near Colesberg must combat during the lambing season.
According to Jan-Hendrik Kleyn, a wool sheep farmer on the Mooifontein farm between Colesberg and Hanover in the Northern Cape, his workers began noticing about three years ago that when his ewes gave birth, warthogs would immediately eat a newborn lamb.
He and a few neighbours obtained a helicopter and shot a large number of warthogs, putting an end to the problem.
“But when my ewes began lambing about two weeks ago, we discovered the same thing happening again. Where the crows fly, you see a sow running off with four piglets, and when you arrive the lamb has been eaten.”
He says warthogs target newborn lambs that are still unsteady on their feet.
The farmers started shooting the warthogs again, and within a week they had killed almost 100 on his farm alone, which covers 500 hectares.
He says they have been shooting the warthogs ever since, killing three or four a day.
Kleyn says it is difficult to quantify the damage or loss of income, as his ewes lambed well this year, but he estimates he has lost about 10% of his lamb crop. His ewes lamb in the field.
Every warthog is as good as a jackal, and as the lambs arrive they eat the lambs nearly hooves and all,” he says.
According to Kleyn, the piglets are the main culprits because the sow teaches them.
Apart from the damage to his lamb crop, warthogs also cause significant damage in the field as they root through the ground. There are now large bare patches in his field, and the warthogs also make holes in fences, allowing jackals to pass through.
Intruders
Prof Graham Kerley, director of the Centre for African Conservation Ecology at Nelson Mandela University in Gqeberha, told Landbouweekblad that, like domestic pigs and bush pigs, warthogs are omnivores. They mainly eat plant material but they are known to scavenge carcasses and there are records of them killing small mammals.
“Predation on lambs is an extension of their feeding style and provides access to high-quality protein,” he says, adding that bush pigs are also known to kill lambs.
Kerley is one of the editors of “Livestock Predation and its Management in South Africa: a Scientific Assessment”, which was introduced to the livestock industry in 2018.
Warthogs historically occurred east of Colesberg, according to archaeological records. However, over the past 50 years they have been introduced to the area, especially by game reserves. These populations have thrived, says Kerley, probably because warthogs benefit from the changes people make to the environment, such as cattle troughs and the availability of irrigated crops, as well as the extermination of predators such as lions, leopards and spotted hyenas. Warthogs are now considered invaders in the area.
“We do not know what the effect of climate change will be on warthog populations and their distribution, but warmer temperatures will be in their favour since they are a tropical species,” says Kerley.
Kerley says warthogs are primarily grass eaters. They also eat shrubs, placing them in direct competition with livestock, and they consume crops, which harms production. In addition, they eat grass roots (rhizomes), which has a detrimental effect on grass stands and loosens the soil, contributing to soil erosion.
Warthogs can have a destructive effect on wire fences as they make holes in them, allowing cattle and problem animals such as jackals to move through more easily. They also like to hide in holes, and they make aardvark holes bigger. If these holes are in dam walls, it can lead to a weakening of the walls.
