It’s been called the strangest animal ever, and it stumped Charles Darwin for years. Now, scientists say that they’ve finally cracked the riddle of where this bizarre beast belongs on the tree of life.

It’s called Macrauchenia patachonica, and it lived about 12,000 years ago during the last ice age. It looked a bit like a camel without a hump, as well as a short trunk for a nose. It was an herbivore that lived in what is now Patagonia in South America.

Darwin found the first fossil of this strange creature back in 1834, and gave them to Richard Owen, a British paleontologist, to investigate further. However, they weren’t able to figure out what kind of mammal lineage it had based on its features.

But authorities now think that Macrauchenia belongs to the group Perissodactyla, which includes horses, rhinos, and tapirs. The study was published in the journal Nature.

“Fitting South American ungulates to the mammalian family tree has always been a major challenge for paleontologists, because anatomically they were these weird mosaics, exhibiting features found in a huge variety of quite unrelated species living all over the place,” said Ross MacPhee, one of the paper’s authors and a curator in the American Museum of Natural History’s Department of Mammalogy, in a 2015 statement from the American Museum of Natural History. “This is what puzzled Darwin and his collaborator Richard Owen so much in the early 19th century. With all of these conflicting signals, they couldn’t say whether these ungulates were related to giant rodents, or elephants, or camels–or what have you.”