Hundreds of Mammals Awaiting Discovery

Invest in Our Planet. That’s the theme for Earth Day 2022, according to EARTHDAY.ORG. It advocates for “creating a 21st century economy that brings back the healing and health of our planet, protects all of our species—including our own—and provides opportunities for everyone on the planet.”

“Protects all of our species” is the part of this year’s focus that’s intriguing me right now. That’s because a new study, published on March 28, 2022, in the Proceedings of the National Academy of Sciences, reports that there are probably hundreds—maybe even more—of so-far-unidentified mammal species around the world. And as this year’s Earth Day, April 22, 2022, approaches, it’s good to be reminded of how much we have yet to learn and how many wonders we have yet to discover about the multitude of lives that surround us.

And just in time for Earth Day 2022, one of those previously unknown lives has come to light: that of a golden bear in Peru.

In plain sight, and in the genes

Researchers say that most of these hidden mammals are small bodied; many of them are bats, moles, rodents and shrews. The reason that a lot of them have escaped notice is because they’re little and look so much like known animals that biologists have been unable to recognize that they are truly different species. Subtle differences in appearance are harder to detect when you’re looking at a tiny animal that weighs only 10 grams than when you’re examining something that is close to the size of a human.

Often, the only way to tell if an animal is different from a known species is to conduct a genetic analysis. So, that’s what a team led by The Ohio State University researchers did. They used a supercomputer and machine-learning techniques to analyze millions of publicly available gene sequences from 4,310 mammal species, as well as data on where the animals live, their environments, life histories and other relevant information. This allowed them to build a predictive model to identify the taxa of mammals that are likely to contain hidden species.

Based on their analysis, the scientists say that a conservative estimate would be that there are hundreds of species of mammals worldwide that have yet to be identified. Biologists, however, would not be surprised by that finding. It’s estimated that only 1 to 10 percent of Earth’s species have been formally described in scientific literature. What’s new about what The Ohio State University researchers did is to predict where these new species are most likely to be found.

In forests, and in small bodies

Where those new species are suspected to be hiding is in the families of small animals, such as bats and rodents. The predictive model also pointed to species that have wide geographic ranges with high variability in temperatures and precipitation levels. And most are also likely to occur in tropical rain forests, which is not unexpected since that’s where most mammal species occur.

But many unidentified species are also likely living here, in the United States. For example, in 2018, a published scientific paper showed that the little brown bat, found in much of North America, is in fact five different species.

That 2018 paper also showed a key reason why it is important to identify new species. One of the newly described bats had a very narrow territory—just around the Great Basin in Nevada—making its protection especially critical. And as soon as a species is named, it matters in conservation and legal terms.

For mammals alone, based on the results of the Ohio State University study, it’s thought that close to 80 percent of them worldwide have been identified. We tend to know a lot more about mammals than many other animals because they’re usually larger—as opposed to ants or beetles—and they typically are more closely related to humans, which makes them more interesting to us. But still, shockingly, at least 20 percent of mammals are still undescribed.

In Peru, a new bear

One of those mammals that recently left that 20 percent bracket lives in Peru. When a team of researchers set out to determine the number of spectacled bears currently living in that country, they got more than they bargained for. Not only did they discover an unknown hot spot for the bears, but they observed for the first time what they’re calling a “golden bear.”

The researchers—who come from the University of Gothenburg in Sweden, the Martin Luther University of Halle-Wittenberg in Germany and the State University of New York at Stony Brook—used facial patterns to identify individual spectacled bears. Tremarctos ornatus are shy creatures: little is known about their behavior and ecology. For example, until the mid-2000s, they were falsely believed to be nocturnal. And because they are so elusive, studying their ecology and figuring out how to protect them is difficult.

But spectacled bears are a keystone species (a species that helps define an entire ecosystem; without it, the ecosystem would be dramatically different or cease to exist) of the Andean Ecosystem. They are the only bears native to South America and are also considered an umbrella species (a species that has large habitat needs, and the requirements for that habitat impact many other species living there). Protecting them would additionally be hugely beneficial for other animals. However, spectacled bears—listed on the IUCN Red List as vulnerable—are suffering from habitat fragmentation and human-bear conflicts.

During their stay in Peru, the research team members also intended to investigate the behavior of rare yellow-tailed woolly monkeys, found only in the Peruvian Andes. But locals told the researchers that bears had regularly been spotted in the Copallin District, located along the Amazon River and which consists mostly of grasslands and a few scattered forests. So, using local guides, the scientists embarked on several research trips in Copallin.

Luckily, the researchers were able to observe spectacled bears on multiple occasions, including up to four bears in a single day. When an animal was spotted, it was photographed, and its behavior and location were recorded. The bears were given individual identities based on their facial patterns, which served as the basis for calculating the population density for the Copallin District. The scientists estimated that there are more than 10 bears per 38.6 square miles, which is at least double what had been previously established.

During their fieldwork, however, the scientists spotted one individual with golden fur and an uncanny resemblance to the popular children’s book character Paddington Bear. According to A Bear Called Paddington, written by Michael Bond in 1958, Paddington also comes from Peru. Usually, a spectacled bear’s fur is almost completely black.

The researchers, who published their results in the journal Ursus in January 2021, point out that their observations may only indicate a local hot spot, and it could be difficult to extrapolate the estimates to larger areas. Still, the discovery that spectacled bears appear in clusters could play an important role in their conservation, because they had been thought to require big territories. Often, setting aside large areas for conservation purposes is not feasible, since increased agriculture and deforestation make it difficult to create vast reserves. Too, protecting smaller areas is more easily accepted by local communities, an important factor to consider. Therefore, small spots where bears gather for feeding, such as in the Copallin District, could be tremendously valuable to conservation efforts.

In awe, on Earth Day

Why the researchers found only that one bear with golden fur remains an enigma. Further investigation is required. But isn’t that the spirit behind Earth Day? Not only should we invest in this place that’s our home, but we should celebrate all the wonderful mysteries still to be found on Earth.

Here’s to finding your true places and natural habitats,

Candy