Lost Species

The Search for Lost Species is the world’s largest effort to rediscover plants, animals, and fungi that have been lost to science for at least 10 years—sometimes hundreds. But, all is not lost. We can protect and restore our planet.

Let's find something wild.

All around the world, across habitats, across taxa and for all kinds of reasons, once-discovered species have fallen off our radar. These lost species are animals, plants of fungi that have gone unseen for years or decades. Some are feared possibly extinct or Critically Endangered.

In order to safeguard these species, we first need to find them.

By the Numbers

From the dark depths of the ocean to freshwater rivers, from lush tropical jungles to remote deserts, the Search for Lost Species spans some of the most remote and uncharted wild places on Earth. There are more than 4,300 lost species across nearly 200 countries.

4,300+
lost species waiting to be found
40%
of those lost species disappeared since 1970
200
countries where lost species remain
100+
IUCN experts guiding the search

View the Full Infographic

Re:wild’s Most Wanted

Re:wild’s list of most wanted lost species highlights some of the rarest and most mysterious species on Earth. These are the species we prioritize—with support from the Colossal Foundation and other donors—because they represent urgent conservation needs, champions ready or already searching for them, and opportunities for conservation action with local partners.

As species are rediscovered, they rotate off the list and are replaced with new species that require attention. The list spans taxa, ecosystems, and habitats around the globe, from land to freshwater to the ocean, and includes species lost for decades as well as those lost to science more recently.

By focusing on these species, we aim to catalyze local and international research and conservation action, mobilize field teams and citizen scientists, and create flagships for broader conservation.

Photo Credit - John C. Mittermeier.

Uncover the Most Wanted Species

What is a Lost Species?

A species is considered lost if it has not been scientifically documented for at least a decade, is not in captivity, and is not listed as Extinct on the IUCN Red List. In 2022, we worked with the IUCN SSC to formalize this language in a published article in Oryx, establishing an international standard.

Species become lost for many reasons including but not limited to: habitat destruction, disease, poaching, or human-wildlife conflict; restricted access due to remote or conflict-ridden regions; naturally small populations or cryptic behavior. In some cases, these species were very rare to begin with, existing in small numbers in small geographical areas where a single disturbance could easily wipe out the entire population.

For more on how we define lost species, the science behind the search, and answers to common questions, explore our FAQ.

Explore Our FAQ

From Lost to Found

Since 2017, the Search for Lost Species and local partners have either supported and/or confirmed 16 of its most wanted lost species, including a tap-dancing spider, an iridescent mole, a fanged mini-deer, and the world’s largest bee.

These rediscoveries inspire hope and catalyze conservation actions. Each story proves that even the most overlooked species can survive—and thrive.

Photo Credit - Simon Robson.

Explore Found Species

Join the Search

There are many ways to take part in the global effort to find and protect species that have been lost to science. From supporting field expeditions and sharing stories, to logging observations on iNaturalist and protecting critical habitats, everyone can help make a difference.

Get Started on iNaturalist

Log Your Sightings
Use iNaturalist to document wildlife encounters—your observation could be the key to rediscovering a lost species.
Support Expeditions
Fund scientific fieldwork and research teams working to rediscover lost species across the globe.
Protect Wild Places
Back initiatives that safeguard habitats, ensuring species have a chance to survive once they’re found.
Share Their Stories
Spread the word on social media and within your community to build awareness and inspire conservation action.

Bringing Lost Species to Life Through Art

Losing a species is akin to losing a beautiful, irreplaceable, priceless work of art. Meet renowned artists who have been inspired to create lost species artwork for the campaign.