The Most Mysterious Animals in the World Are Heading Toward Extinction, Scientists Say

More than half of “data-deficient” species may be on the brink of dying out, reports a new study.
More than half of “data deficient” species may be on the brink of dying out, reports a new study.
The Kottigehar dancing frog, which is considered a Data Deficient species. Image: Girish Gowda
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Many scientists believe we are in the midst of a sixth mass extinction, driven by human activity, which threatens countless species around the world. 

Now, scientists have found that the most mysterious animals on Earth—classified as “Data Deficient” (DD) because so little is known about them—are much more vulnerable to extinction compared to their better-studied “data-sufficient” counterparts, reports a new study. The finding points to problematic biases in conservation priorities, like those laid out in the International Union for Conservation of Nature Red List of Threatened Species.


A team led by Jan Borgelt, a PhD student in ecology at the Norwegian University of Science and Technology, trained a machine predict the extinction risks of 26,363 species on the Red List to a high level of accuracy, using criteria such as their geographical locations, exposure to the effects of climate change, and pressures from humans and invasive species

When the researchers applied the algorithm to a subset of 7,699 DD species, they found that a whopping 56 percent of them are likely at risk of extinction, a figure that is twice as high as the Red List’s estimate of 28 percent for this group, with amphibians particularly hard hit at an extinction risk of 85 percent. 

The results suggest that “DD species as a group may in fact be more threatened than data-sufficient species,” a reality that implies “current conservation concerns could, in fact, be underestimated,” according to a study published on Thursday in Communications Biology.

“Knowing and assessing which species exist, where they occur, and how threatened they are, is the very foundation of all conservation related actions and research that happens after this knowledge has been gained,” Borgelt said in an email. “In our research unit, we work with analyzing different human pressures on ecosystems, including plastic pollution, land use or hydropower generation.” 


Borgelt added that the IUCN Red List, which contains information about 140,000 species, is one of the most important resources for this research, but that the “data-deficient” group has “a major obstacle” for extinction risk assessments.

“Ultimately, we, and also other practitioners that rely on the IUCN extinction risk assessments, are left with the arbitrary decision of handling these ‘Data Deficient’ species appropriately,” he said. “As a consequence of this, Data Deficient species had to be excluded from many analyses. The results of this study help us to account for Data Deficient species more appropriately than previously done.”

In addition to the alarming conclusions about amphibians, the team’s findings show that 40 percent of ray-finned fish, 61 percent of mammals, 59 percent of reptiles, and 62 percent of insects that fall under the DD category may be facing extinction. Many of these species have small ranges in isolated areas, which makes them particularly susceptible to threats. 

Regions such as central Africa, southern Asia, and Madagascar proved to be potential extinction hotspots for DD land species. As many as half of DD marine species along the world’s coasts might be at risk of extinction, especially along the eastern Atlantic and in the Mediterranean basin.  


Scientists estimate that many species have already died out before they could be described, a term known as “dark extinction.” But DD species have at least been described, though they are not well-understood, offering some potential hope that they might be conserved with more targeted efforts.

“Many Data Deficient species could be threatened by extinction but are currently ‘overlooked,’” Borgelt said. “Our results suggest that we should try to include Data Deficient species whenever possible, for decision-making, policy-making, and in biodiversity analyses.” 

“Another takeaway is that machine learning and data science could be utilized more,” he concluded. “Not to replace experts—they remain vital for making accurate assessments of extinction risk—but to assist, to guide, and to allocate resources to those species that could actually be threatened by extinction but whose true risk remains to date unacknowledged.”