Now then: The world’s biggest invasive species is doing better than people thought. A recent article in Nature says in part:
A few years ago, researchers estimated how fast the animals were reproducing, to project that about 98 hippos were living along the country’s Magdalena River and its tributaries in 20201. But the new study, for which a research team counted the animals in person, by drone and using other tracking methods, estimates that there are 181–215 of them residing in Colombia.
“Before, one argument against dealing with the hippos was that our information was limited and our arguments theoretical,” says ecologist Rafael Moreno, who participated in the study while at the Alexander von Humboldt Biological Resources Research Institute in Bogotá. “But we have put that argument to bed now. This study shows that this is a real issue, and that the state must act urgently.”
I’ve never been to the area in question, but it sure seems like an ideal habitat for hippos. And it’s clear that people who live in the area are right to be concerned about Pablo Escobar’s escaped ‘cocaine hippos’ (not to be confused with Cocaine Bear) living in the area, as in Africa, hippos are known to be extremely dangerous animals. In fact, in many areas, hippos are responsible for more injuries and deaths than other megafauna, including lions and the notorious Cape buffalo.
Nature describes several mitigation efforts, including sterilization and relocation, but (speaking as a biologist myself) they only pay lip service to the most obvious technique: Culling. That means, candidly, shooting the damn hippos.
Were this Florida or Alabama, say, instead of Columbia, there would be an obvious answer; declare an unlimited open season on the hippos, and spread the word that they’re good to eat. (This may even be true; I’m not familiar with anyone who has tried.) But hippos swordlike tusks are ivory, and ivory is valuable. That would be a good incentive.
Invasive species have been a problem for centuries. And it’s not always a human-caused problem, although it frequently is. And, sadly, mitigation efforts normally fail. Look at starlings in North America, rabbits in Australia, rats almost everywhere.
Hippos, being slower-breeding megafauna, may be more amenable to reduction. But I suspect the only method that will work in the end is, to put it bluntly, killing them.