We often tend to think of mammals – the group that includes us – as rather familiar, so it might come as a surprise to find that many mammal species have only just been discovered over the past few decades. In fact, according to new research, there are many more mammals than we thought, and they're being discovered at a relatively rapid rate.
The study, published in the Journal of Mammalogy, highlights that in the past 12 years, more than 1,000 new mammal species have been found. Some are totally new discoveries, while others are the result of genetic studies separating what was previously thought to be one species into two or more, like the recent discovery of a new species of orangutan.
The number of mammal species on record has been rising fairly rapidly. There were 4,631 in 1993, 5,416 in 2005, and today there are 6,495. This increase in biodiversity is almost as high as 20 percent, although unfortunately 96 species have been lost in the past 500 years, and this number is only likely to go up as a result of climate change, habitat loss, and pollution.
Around 25 new species of mammal are being recognized each year, and a list of all living mammals can be found online in the Mammal Diversity Database. Most new species have been found in Central America, South America, and the Caribbean, but high mammal densities can also be found in tropical parts of Africa, Asia, and the Indo-Pacific.
Just some of the mammals discovered in recent years include a coconut-cracking tree-dwelling giant rat, a snazzy pink river dolphin, and three teeny tiny mouse lemurs.
Previously, taxonomic data in the form of the Mammal Species of the World series has been released sporadically, the latest being published in 2005, so there have been large time gaps between estimates of mammal biodiversity. It is only now that the past few years of discoveries and research have been fully incorporated, providing the best picture yet.
To create the new list, a team of researchers reviewed over 1,200 publications regarding mammal taxonomy from the end of 2003 to now. Their update includes recognizing 1,251 new species, 172 unions, 88 new genera, and 14 new families.
"Mammals have lagged behind other groups in their taxonomic record-keeping, which is surprising given their relevance as models for disease and human origins,” said Yale University’s Nathan Upham, senior author of the new study. “It's convenient to ignore taxonomy, so many people do – but it's the essential language for how researchers communicate through time to study biological diversity."
Conserving mammals is important – their wide variety means they play hugely important roles in all sorts of natural ecosystems and food chains around the planet. Let’s hope there are many more exciting new discoveries ahead.