A lawsuit was filed in South America last year to save dozens of the animals - which are non-native and considered too numerous – from being killed.
The US District Court for the Southern District of Ohio accepted the hippos’ status during legal proceedings. Animals are considered property under American law, which limits their rights.
In the 1980s, Colombian drug trafficker Escobar imported four African hippos for his private zoo, and after his death in 1993, the animals remained on his property.
In the following years, they escaped, moved to the Magdalena River, one of the country’s main waterways, and reproduced at a rate that some ecologists considered unsustainable. Experts argued their numbers could grow “out of control” within decades.
The US-based Animal Legal Defense Fund (ALDF), acting for 100 hippos that are descendants of Escobar’s imports, filed a lawsuit against the Colombian government over its plans to kill them.
In Colombia, animals have the right to bring lawsuits to protect their interests.
ALDF executive director Stephen Wells said the court’s order was “a critical milestone in the broader animal status fight to recognise that animals have enforceable rights”.
While the legal case continues, a regional environmental agency has started to give some of the animals a contraceptive drug.
But the ALDF says it wants to administer a different contraceptive, one already successfully used on hippos in zoos, claiming the safety of the government contraceptive is unknown.