Like their owner before them, the hippopotamuses that once belonged to South American drug lord Pablo Escobar are apparently running through the nation of Colombia, virtually unchecked.

Escobar built a zoo for his son in the 1980s; as such, according to a report by United Press International, roaming free across the acreage of his ranch -- Hacienda Napoles, in Colombia's Puerto Triunfo, which is about 200 miles northwest of the capital, Bogotá -- were several elephants, giraffes and four hippos.

After Escobar was shot and killed by Colombian National Police in 1993, the elephants and giraffes reportedly ended up in various zoos across the country.

Yet, over the last 21 years, the hippos have remained free to roam -- and free to procreate. And now, there are many more than just the original four of what the Greeks call "river horses."

When Escobar's ranch was re-purposed as a park after years of neglect, local environmental programs assumed responsibility for upkeep and discovered the hippos have been rather fruitful and multiplied during the past two decades-plus.

Officials say the park now holds an estimated 50 to 60 individual hippos, although local reports suggest the population of the giant plant-eaters has already reached well beyond the zoo's limits.

Carlos Valderrama, a conservationist with the local group Webconserva, told the BBC some locals were taken by surprise when they came face-to-face with a hippo in a happened upon a hippo in a nearby river.

"They found a creature in a river that they had never seen before, with small ears and a really big mouth," he said. "They were all saying, 'How come there's a hippo here?' ... We started asking around and of course they were all coming from Hacienda Napoles."

Valderrama and others argue the growing hippo population, like so many other invasive species, threatens the area's biodiversity, not to mention the area's human population.

It's estimated hippos kill an estimated 200 people or more annually.

Meanwhile, authorities don't have a clear answer to the hippo problem, which is progressively getting worse as the creatures, living in what is considered to be an ideal hippo environment, continue to breed.

Some have suggested rounding up all the loose animals and building a better enclosed habitat with reinforced fences. That, however, would cost at least $500,000, a chuck that environmentalists want spent to protect species native to Colombia.

Others believe the male hippos should be killed.

Some zoos in the area have adopted the youngest of the hippos, but the adults remain free and, in some cases, tromping through public places.

In an interview with the BBC, Mexican novelist Juan Pablo Villalobos compared the hippo problem to Colombia's ongoing struggle with drug trafficking.

"It's like a sign of what's happened in Colombia in the last 20 years," Villalobos said.. "And this past is still present, and Colombians maybe don't know how to deal with this memory, with Pablo Escobar's heritage."

Said Valderrama of Webconserva: "Everything happened because of the whim of a villain."