I can tell you how many times I've gone on vacation and accidentally discovered a new species: exactly zero. 

Of course, I'm not researcher Charlie Gardner. While camping on a tiny, uninhabited island off the northern coast of Madagascar, Gardner and his wife, nature photographer Louise Jasper, stumbled across a new population – and maybe even a new species! – of dwarf lemurs

Lemurs are a type of adorable and endangered primate found only on Madagascar, but until now, nobody thought they lived on the craggy northern islet known as Nosy Hara (yes, that's the real name). The only exception is a record of a French teacher bringing a few crowned lemurs (Eulemur coronatus) there in the 1980s, which haven't been seen since. 

But the 1980s transplants were not the petite gray-and-white lemurs Gardner and Jasper observed during an evening stroll on Nosy Hara this past April. Two nights in a row, the pair spotted the dwarf lemurs among the foliage of the rocky island's few forested areas. 

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The lemurs on Nosy Hara appeared completely unafraid of the two human visitors. Image: Louise Jasper

"The animals appeared quite small, and they were incredibly tame, showing no fear of us at all," Gardner told the BBC. In a description of the lemurs published in the journal Primates, he and Jasper reported, “We felt that we could have caught them by hand if we had attempted to do so.”

These two clues – being unusually small and unfazed by big potential predators like humans – are characteristic of isolated island species, suggesting that Nosy Hara's population may have been there long enough to be considered a species separate from lemurs on the mainland.  

While similar in appearance to the small, greyish dwarf lemurs of western mainland Madagascar, the Nosy Hara residents are separated by sea and more than 40 miles (64km) from this potential relation. So how might these adventuresome primates have arrived at Nosy Hara? Perhaps the same way that lemur ancestors first made it to Madagascar from mainland Africa: crossing the ocean on rafts of floating vegetation.

While dwarf lemurs aren't the smallest group of primates (that distinction belongs to their close relation, the mouse lemurs), they're not far off. Nocturnal and fruit-eating, they generally measure between 7.6 inches (19 cm) and nearly 11 inches (27 cm), not including their tails, which can be nearly as long as their bodies. And because those long tails can store fat for lean times, drawf lemurs are able to hibernate, a trait unique among primates.

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The dwarf lemurs were spotted among the foliage of Nosy Hara's few forested areas. Image: Louise Jasper

So is this new population a separate species? Only further research will tell – and that process has been a complicated one in particular for dwarf lemurs, whose genus (Cheirogaleus) has been dubbed the “most confused” of any of the lemur groups. Their introduction to science in 1812 didn't exactly go off without a hitch.

French zoologist É. Geoffroy St. Hilaire defined the first species of dwarf lemur based on what he thought to be someone else's "faithful" illustrations from the field. But these depictions actually turned out to be drawn from memory, a point made obvious by the fact that the animals were shown with claws and other features that dwarf lemurs don't actually have. Whoops.

This trend continued for dwarf lemurs through the 1900s as scientists delineated new species based on only about 50 specimens sitting in European museums. Today, thanks to modern techniques, we know of as many as 18 (perhaps going on 19) different species. 

While the logging and hunting that are decimating populations on mainland Madagascar likely aren't an issue for Nosy Hara's isolated dwarf lemurs, these tiny primates may not be in the clear. As a population limited to a single island comparable in size to New York's Central Park, they may be extremely vulnerable to extinction from disease or drought, making them perhaps the world's rarest primate.

Bonus fact: Nosy Hara is known for producing another uniquely miniature species: Brookesia micra, the world's itty-bittiest known species of chameleon, which is small enough to balance comfortably on a match head.