How many mammal species are there left to be found? It sounds like an unanswerable question, after all you can’t count something you don’t know. And yet using statistics, researchers can make a pretty good estimate. They have found that there are likely 303 undiscovered species of mammals still roaming the planet.
Currently, there are around 5,557 mammals that have been described globally over the last few hundred years. These range from the largest animal ever to have lived on the planet to a bat that weighs the same as a bumblebee.
Because of their often enigmatic nature, mammals have received a fair amount of attention from scientists over the years, leading many to think that there might not be a great deal left to discover.
“With extinction rates increasing, it's extremely important to be able to find new species before they disappear if we want to be able to understand the world that we're living in,” explains Molly Fisher, who led the study that has been published in the journal Ecology and Evolution, in a statement.
By adapting a statistical model that was previously used to estimate the total number of plant species, including the number of species discovered every five years from 1760 through to 2010 and how many taxonomists were involved, the researchers figured out how many mammal species there are in total.
This came in at 5,860 species, and by taking away how many have been discovered to date, they could reveal that there are likely still 303 left to be found.
When applying this data geographically, they could see where most undiscovered species are likely to be located. The tropics contained the most number of mammal species – and correspondingly the greatest number of undiscovered ones – but they also revealed that the Palearctic region, made up mainly of Eurasia, had the highest percentage of mammals yet to be found.
“We expected that the tropics would have the most species because the tropics are the least well studied and have a lot of cryptic species,” explains Fisher. These are ones that look a lot like other species we already know about, such as the Tapanuli orangutan that was described earlier this year.