(CNN)Madagascar is home to many unique species, including a variety of lemurs. But there's one species living in the island's forests that scientists hadn't quite been able to figure out until now: cats.
The mystery of Madagascar's forest cats
University of Colorado at Boulder anthropology professor Michelle Sauther has been studying primates and lemurs on the island nation in the Indian Ocean for 30 years. And during that time, she's seen a lot of cats in the forests.
But cats aren't native to Madagascar, which is one of the world's largest islands.
"When I first started working in Madagascar, I noticed that these cats all seemed to look the same," Sauther said. "They were big, and they were always the same color."
They're known as the "forest cats" of Madagascar, sharing straight tails and a "mackerel" tabby coloring that blends well with the forest. They also look different than the village cats that people keep as pets on the island.
Local populations use various names in their languages to call them "ampaha," which translates to "cat run wild," or "kary" or "saka kary," both of which also suggest "wild cat."
Over the years, scientists have speculated that the animals are truly domestic cats who have become wild or feral, or that they're an introduced wildcat or domestic-wildcat hybrid, according to a new study.
The free-ranging forest cats have been found across the island in Ankarafantsika National Park; Bezà Mahafaly Special Reserve; Makira Natural Park; and the Masoala peninsula.
Sauther and her colleagues wanted to study these cats to understand where they came from and how long they've been on the island. They set up cage traps with cameras and baited with live mice at the sites where the cats are known to live in the forests of western and southwestern Madagascar.
But don't worry -- the mice were safely ensconced in their own comfy little cages with bedding and food.
Altogether, the researchers captured three forest cats from the Bezà Mahafaly Special Reserve and 27 forest cats from Ankarafantsika National Park. The results of their study published last week in the journal Conservation Genetics.
Blood, fecal and hair samples were taken, along with dental impressions and photographs of the cats after they were sedated. After the samples were collected, the cats were released back into the wild.
The samples allowed the team to run a DNA analysis, which was then compared to 1,900 domestic and wild cat species from around the world.
The answer to Madagascar's mysterious cat species was waiting in the genetics.
The researchers discovered that the forest cats are descendents of domestic cats from the Arabian Sea region, including the islands of Lamu and Pate in Kenya, as well as Dubai, Kuwait and Oman in the Persian Gulf. There are also additional influences from India and Pakistan, according to the study.
They consulted historical information and discovered that the cats probably arrived on the island on trade ships along early Arab trade routes.
Ships at Arabian Sea ports crossed marine trade routes beginning thousands of years ago, from the late second millennium BC through 1862, when the Age of Sail was ending, according to the study. The Cinnamon trade route across Asia and Europe, including stops at Madagascar, was made favorable by cold monsoon winds from October to March.
There are also known Arab influences across the island, evident in languages, manuscripts including Arabic characters and an archaeological site containing a large mosque from the 12th century.
"They would come down along the East Coast of Africa," Sauther said. "They would stop at the islands of Lamu and Pate, and then it's just barely a jump to go over to Madagascar. [The cats] were probably part of the maritime ships that came to Madagascar along these Arab routes."
The cats took well to island life, and their descendants live in its forests today. Understanding more about the forest cats will also enable researchers to determine if they're having a negative effect on wildlife. Cats can be regarded as an invasive species that can destroy native populations -- something researchers have witnessed in New Zealand, Hawaii and the West Indies.
On Madagascar, villagers don't like the cats because they eat their chickens. And Sauther and her colleagues witnessed the forest cats stalking lemurs. Lemurs are unique to Madagascar, and they're considered to be one of the most endangered animals in the world.
"The real worry is: What are these cats doing?" Sauther said. "Are they posing a threat to animals in Madagascar? Maybe they're just part of the local ecology. That's not to say they're not a threat, but we need to understand their biology and their history to understand how we proceed in terms of conservation policy."
More observations and studies about forest cats will help the researchers determine if they pose a threat. But for now, the mystery of where the forest cats came from has been answered.
"Cats have essentially gone with us everywhere we've gone," Sauther said. "We can see that journey of humans and their pets going back pretty deep in time. We now know that these mysterious cats are domestic cats with a really interesting backstory."