Tropical rainforests must be conserved to protect the last few remaining musky rat-kangaroos, researchers say.

The musky-rat kangaroo or Hypsiprymnodon moschatus is considered a living fossil because it hasn't changed much over the past 26 million years. The animal is the smallest member of the kangaroo family, measuring just 208-341mm long with a tail measuring  65-123mm. 

A latest study conducted by the University of Queensland and the University of New South Wales researchers, found that the animal can't survive outside tropical rainforests, which could be a reason for its low population.

 "We must carefully monitor the tropical rainforest because if climate change does affect it, the musky rat-kangaroo, and possibly other species, will have nowhere else to go," said Dr Kenny Travouillon, from UQ's School of Earth Sciences. "The musky rat-kangaroo, along with the cassowary, is one of only two species essential to the rainforest as seed-dispensers.

Their research was based on fossilized remains of ancient species of the musky-rat kangaroo. The study team found that some 20 million years ago, there were several species of these tiny kangaroos. However, today, there is just one species that lives in a small rainforest area in north-east Queensland.

According to the researchers, these animals never ventured out of tropical rainforests to find shelter in other environments such as the temperate forests.

"The finding is also significant because such discoveries are extremely rare, with only two other fossil species of the musky rat-kangaroo recovered previously," Dr Travouillon said in a news release. Such finds help us better understand how animals and ecosystems evolve through climatic change, allowing us to better predict their responses to future changes and protect the most vulnerable species.

The study is published in the Journal of Vertebrate Paleontology.

The International Union for Conservation of Nature's Red List has listed the musky-rat kangaroo as Least Concern. The agency says that despite the low number of the animals, the species doesn't face any major danger and has a stable population.