More than 441 new species of animals and plants, including a monkey that purrs, have been discovered in the Amazon rainforest over the last four years.

The vast rainforest of the Amazon has remained highly unexplored for a long time. However, over the last few years, biologists and nature enthusiasts have taken the initiative to discover rare species that exist in the wild and this includes exploring the Amazon rainforest. In a new report, the World Wildlife Fund (WWF) revealed that between 2010 and 2013, more than 441 new species of animals and plants have been discovered in this area alone. The total is broken down into 258 plants, 84 fish, 58 amphibians, 22 reptiles, 18 birds and one mammal. Moreover, this tally doesn't include the countless insects and vertebrates that were discovered during this period.

"These species form a unique natural heritage that we need to conserve. This means protecting their home - the amazing Amazon rainforest - which is under threat from deforestation and dam development," said Claudio Maretti, Leader of Living Amazon Initiative, WWF.

Some of the fascinating discoveries outlined in the WWF report include:

-          The Caqueta titi monkey, which is one among the 20 titi monkey species that live in the Amazon forest. Reportedly, the monkey purrs like a cat when very content.

-          The Flame-patterned lizard was found from the hatchlings of eggs collected by scientists in the Colombian Amazon and hasn't been found in the wild since the collection of these eggs. Researchers speculate they might be endangered.

-          A beautiful pink orchid was one of the new plant species discovered in the rainforest. The species has been named Sobralia imavieirae.

Other discoveries include a brightly colored snake from the "Lost World", the Vegetarian Piranha and a thumbnail-sized frog.

"Compiling and updating data on new species discovered in the vast extension of the Amazon over the last four years has shown us just how important the region is for humanity and how fundamentally important it is to research it, understand it and conserve it. The destruction of these ecosystems is threatening biodiversity and the services it provides to societies and economies. We cannot allow this natural heritage to be lost forever," Maretti said.

Many of these species are found exclusively in the Amazon rainforests and researchers fear that the destruction of these forests may result in the loss of many species yet to be discovered by mankind.