Earth may have three million undiscovered animal species

Earth’s biodiversity can be elusive, and most animal species lie beyond our immediate awareness. Researchers keep shining a light on hidden corners of the planet, eager to pinpoint the creatures we share our world with.

​A new project by scientists from Imperial College London, UCL, Dalhousie University, and the United Nations Environment Programme World Conservation Monitoring Centre is tackling this challenge with a fresh simulation. 

The experts want to understand how many terrestrial animals exist and how quickly new species come into being.​

The research was led by Professor James Rosindell, who studies how species originate and spread across land-based habitats. He is based in the Department of Life Sciences at Imperial.

Millions of animal species remain undiscovered

The newly developed simulation uses modern ecosystem modeling to estimate the total number of land-dwelling animals, as well as the rate at which they form new species. It suggests there could be anywhere from 1 million to 3 million undiscovered animal species.

Many of these creatures may be too small, too rare, or too remote to be discovered easily. This hidden diversity has significant implications for our broader understanding of life’s complexity.

Building on established theories

The team’s approach merges the Madingley model – a framework that forecasts organism abundance worldwide – with neutral theory, which explores how species numbers connect to speciation rates and population sizes.

This unification offers a way to account for the presence of unclassified species in different ecosystems.

“A key novelty of this study was that we plugged together the Madingley model and neutral theory for the first time,” said Professor Rosindell.

This combination allowed the researchers to spot patterns that might otherwise remain hidden, offering a window into the subtle dynamics of how species appear.

Small animals and carnivores evolve faster

Smaller-bodied animals often show faster speciation, the process by which populations split to form new species.

“The two main questions we wanted to answer were how many species of terrestrial animals there are on the planet and how quickly do new species of terrestrial animals evolve,” said Professor Rosindell.

The simulation also suggests that carnivores, when matched by size to herbivores or omnivores, evolve at a higher rate. This pattern adds another layer of nuance to how diet shapes long-term survival and adaptation.

Implications for conservation

Policymakers often struggle to allocate resources for wildlife protection due to a lack of precise data on species numbers. Understanding which groups evolve fastest or exist in smaller populations can help shape conservation strategies that prioritize those most at risk.

High speciation rates in smaller animals or carnivores do not guarantee resilience, especially if habitats are shrinking due to human activity.

Protective measures that ignore these rapid-evolving groups might miss potential threats to the broader ecosystem.

A model of all life on Earth

The team envisions a future where this model is refined to project biodiversity changes under different climate scenarios.

“The end result will be a model of all life on Earth that has the ecological and environmental elements necessary to answer questions around what will happen under different climate change and habitat loss scenarios,” said Professor Rosindell.

Such forecasts may indicate which areas and species will suffer most if temperatures rise or landscapes become fragmented. Conservation plans may then focus on these hotspots before losses become irreversible.

Significance of the study

Scientific estimates suggest that a large percentage of Earth’s species remain unrecorded. Identifying these organisms is essential for a more balanced view of how ecosystems function and how we fit into the mix.

Accurate knowledge of undiscovered species counts and speciation rates also helps predict how ecosystems might shift if certain animals disappear. In complex food webs, the loss of a single group can trigger wide-ranging effects across entire habitats.

Refining global biodiversity models

Researchers are expanding their data sources to include genomic studies, citizen science programs, and collaborations with local communities. These contributions can refine how the Madingley model and other tools forecast global trends in life’s variety.

Some scientists hope to extend these methods to marine environments, polar regions, and mountainous terrains. Even extreme locations could harbor unknown organisms that hold clues to how life endures under tough conditions.

Classifying new animal species

Determining which discoveries represent undiscovered animal species versus variations of known forms is no small task. Taxonomic disagreements, limited funding, and a shortage of specialists often slow the cataloging process.

Better collaboration between geneticists, ecologists, and local experts might streamline how newly found organisms are documented. Standardizing these efforts will likely improve the accuracy of predictions for how species arise and vanish.

A new chapter for biodiversity research

Efforts to map the planet’s living diversity are reaching a turning point, propelled by these integrated models. Detailed forecasts of species formation and decline could empower societies to make more informed decisions about preserving life’s richness.

“The exercise enabled us to estimate the number of terrestrial species of life on Earth, including all the numbers unknown to science, but it has great potential beyond this in future work,” said Professor Rosindell.

Each refinement of the simulation can reveal new facets of how animal populations take shape.

By focusing on the interplay between ecology and evolution, scientists can spot vulnerabilities before they become crises. This perspective might help protect not just iconic animals, but also the humble creatures that quietly maintain critical processes in soils and forests.

Charting tomorrow’s path

As climate change and human expansion accelerate, time is running short to prevent irreversible damage to fragile animal species.

Modeling efforts that highlight hidden diversity can motivate communities and governments to invest in safeguarding lesser-known parts of the natural world.

Although massive in scope, these simulations offer the precision needed to foresee where interventions can make the biggest impact. That knowledge could be the difference between a resilient planet and one where key ecosystems collapse.

Looking beyond terrestrial animals

Many experts believe a similar approach could unlock answers about ocean life, which remains largely uncharted at great depths. Merging ecological theories with real-time observations from submarines and remote sensors could uncover countless marine species.

Such an undertaking would offer a broader perspective, connecting land-based knowledge with what lies beneath the waves. A complete vision of Earth’s inhabitants can only emerge by embracing every corner of the planet

This simulation is a step toward seeing the full scope of Earth’s biodiversity. Researchers are hopeful it can help people recognize our shared responsibility for safeguarding the hidden richness that sustains us all.

This endeavor symbolizes a growing momentum in ecological research, where data-driven models inform policy and public awareness.

The results hint at a deeper story about our planet’s adaptability and the remarkable creatures that keep evolving.

The study is published in the journal Systematic Biology.

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