How many hippos are too many? Proposed hippo cull raises questions

Is a cull really necessary?

The hippo population on the Luangwa River is currently the largest in the world. The International Union for Conservation of Nature (IUCN) estimates that around 25,000 hippopotamus are living in the Luangwa River and notes that there may be as many as 42 hippos per square kilometer on the river at its highest density. In fact, around 20 percent of the world’s surviving hippos are found in this single river — a remarkable conservation achievement by Zambia. 

But is this a rare reservoir of wild abundance that should be celebrated or out-of-control hippos that desperately require lethal management? Currently, the IUCN Red List categorizes hippos as vulnerable. With 115,000-130,000 hippos in the world, they are significantly rarer than the African elephant. The hippo’s global population fell during the late 1990s and early 2000s, but has since plateaued. They remain imperiled by ongoing habitat loss and degradation as well as poaching for their meat and ivory — their teeth. 

“Given the number of hippos in Zambia, at a national scale, the proposed cull number seems reasonable,” Rebecca Lewison, the chair of the IUCN Hippo Group and a professor at San Diego State University, said. 

“In general, culling is an established practice that can be effective in reducing populations,” she added.

According to government, one of the primary reasons for a cull is the fear of an anthrax outbreak. This is hardly unfounded as anthrax outbreaks have been seen among hippos populations in Tanzania and Namibia last year. While most of us know of anthrax as a deadly poison used to terrorize people, it is a bacteria that most commonly hits ungulates like cows, sheep and, yes, hippos. It tends to hit hippos during drought years when their river dries up. 

“Anthrax is a very deadly disease and people are very susceptible to it,” said Corinne Kendall, Curator of Conservation and Research at the North Carolina Zoo, who has studied hippos, vultures and anthrax. 

But that doesn’t mean hippos struck by anthrax would likely spread it to humans.

“Barring eating meat from an animal that’s died from [anthrax] or going up and handling carcasses…one should be able to avoid anthrax,” Kendall noted.

No humans were infected in either Tanzania or Namibia during the anthrax outbreaks.  “The concern with anthrax is that it will spread quickly through the hippos and it does have the potential to spread to other animals, like lions, elephants and giraffe,” Kendall noted, though she added these species are less likely to be hard hit due to their different behavior and diets.

No one wants anthrax infecting their wildlife — let alone their people. But there is little guarantee that killing a few hundred hippos could prevent such an outbreak. 

Nor, it seems, is there agreement that the hippos are overpopulated. 

“We have to date seen little evidence to suggest hippos are ‘overpopulated’,” said Mark Jones, Head of Policy, at Born Free Foundation. 

Kendall notes that managers must have “really good scientific data about the populations” any time culling is considered. She adds that “it’s absolutely critical” to know that the population is significantly above normal.

The government did not respond specifically to the question of overpopulation, but even an international hunting groups said more information was needed. 

Pay to shoot

“It has been documented that the act of culling removes excess males and frees resources for the remaining female individuals, leading to increased births and facilitating rather than suppressing population growth rate,” reads a 2013 paper by Chansa Chomba with the Zambia Wildlife Authority.

Chomba, also found in his research that past culls had little impact on the population. The population on Luangwa has been relatively stable over recent decades after rising from near extermination. 

Given Chomba’s research, one has to wonder if this cull is really about something else. If it’s actually about decreasing the population, killing 250 animals via trophy hunting probably won’t do it. For big mammals, hippos have a quick gestation time — eight months — and the population could quickly recover. 

Moreover, using trophy hunters is arguably an odd strategy if the goal is to decrease the population. The death of a bunch of old males will do little to decrease the population and may even, as Chomba’s paper suggests, lead to a baby boom. 

The cull has been blasted by Peter Sinkamba, the president of Zambia’s Green Party. 

“The Luangwa valley is not overpopulated as they claim,” he said, claiming that the population has actually dropped by 14-20 percent in the last 30 years. 

“The culling policy is motivated by pure greed,” he added. 

recent article alleges that the cull really isn’t about too many hippos but about a poorly-written contract signed with hunting outfits in 2016. According to the story, government is looking to avoid a lawsuit by Mabwe Adventures Limited for cancelling the cull last time by giving them, via Umlilo Safaris, another chance at killing hippos. 

Hippopotami, or in Greek “water horses,” used to fill the Nile River. There was once an Egyptian Goddesses with the head of a hippo. Today, these aquatic anomalies are not only extinct in the Nile, but across all of northern Africa. A hippo there would now seem to many unnatural. Though their ancestors would view today’s Nile with shock and fear. They’d probably ask: where are the floods? The abundant fish? The hippos? There used to be so many hippos.