In the 1980s, notorious drug lord Pablo Escobar created a family zoo with amazing exotic animals in Colombia, which includes rhinos, giraffes, zebras, and hippos. When Escobar’s empire collapsed in the ’90s, the animals were sent to zoos — except for the four hippos, now considered an invasive species whose waste is wreaking havoc on the Colombian aquatic ecosystem, according to a new study published in the journal Ecology.
Escobar’s four hippos have since turned into 80 hippos. Researchers from the University of California, San Diego and the Universidad Pedagógica y Tecnológica de Colombia used two years of studying the water quality and microbiomes of lakes with hippo populations and comparing them to those without. Hippos are nocturnal animals who feed on land during the night and use their days cooling off in the water, and the large amounts of waste they’re excreting into the lakes are changing the water’s chemistry and oxygen levels, the researchers found.
It happens hippo poop is fertilizing toxic algae and bacteria. This can start to problematic algae blooms similar to red tides, which cause disease in humans and animals, according to the study.
Hippos are challenging to catch and dangerous to face, the researchers noted in a press release. The Colombian hippo population will likely proceed to grow drastically in the coming years, which could greatly change the aquatic ecosystem as they communicate more with local animals, like manatees and river turtles found in rivers.
“If you plot out their population growth, we show that it tends to go exponentially skyward,” Jonathan Shurin, a biological sciences professor at UC San Diego and lead author of the study, said in the release. “In the next couple of decades there could be thousands of them. This study suggests that there is some urgency to deciding what to do about them. The question is: What should that be?”