27 New Species, Including Four Mammals, Discovered in “Human-Dominated” Peruvian Rainforest

New species include an amphibious mouse, a blob-headed fish and a tree-climbing salamander

ARLINGTON, Va. (Dec. 20, 2024) – A Conservation International expedition into the Alto Mayo Landscape has uncovered 27 species that are new to science including four new mammals, eight fish, three amphibian and 10 butterfly species. The discoveries are remarkable given the region’s high population density. The findings reinforce the critical importance of sustainable ecosystem management to ensure that biodiversity thrives even in human-influenced areas.

Editors note: High-resolution images of the discoveries are available here and the report is available here. Click here for an expanded web page with additional information, including a map of the region.This press release is also available in Spanish here.

The Alto Mayo Landscape, spanning the Andes to the Amazon and including the Alto Mayo Protected Forest, is a complex mosaic of ecosystems and communities, including Indigenous territories, towns and cities. Over 2,000 species were recorded during the 38-day survey, highlighting the critical importance of conserving this region.

“Discovering four new mammals in any expedition is surprising – finding them in a region with significant human populations is extraordinary,” said Trond Larsen, who leads Conservation International’s Rapid Assessment Program in the Moore Center for Science. “This is a vibrant, dynamic mosaic of ecosystems, both natural and anthropogenic, that we must maintain and restore if we hope to protect the species found there.”

Key Findings

• 151 Mammals: Four new to science, including a bat, a squirrel, a spiny mouse and an exceedingly rare amphibious mouse. At least 12 of the 151 are threatened with extinction.
• 68 Fish Species: Eight new to science, including a bizarre ‘blob-headed’ fish for which the function of its unusual head remains a mystery.
• 45 Reptiles and Amphibians: Three amphibians new to science – a rainfrog, a narrow-mouthed frog and a climbing salamander.
• 289 Insects: Including 218 butterfly species and 71 scarab beetles. 12 insects are new to science, including 10 butterflies and two beetles.
• 536 Birds: A spectacular diversity of species, including 26 threatened with extinction.
• 955 Plant Species: 10 threatened with extinction, including rare orchids and other flora found only in this region.
• Ongoing Discoveries: 48 species of plants and animals observed during the expedition may also be new to science and require further research for confirmation.

Beyond the newly discovered animals, the expedition also observed 49 species that are considered threatened by the IUCN Red List, including two Critically Endangered primates (Peruvian yellow-tailed woolly monkey and San Martin titi monkey), two Endangered bird species (speckle-chested piculet and long-whiskered owlet) and an Endangered harlequin frog (Upper Amazon Stubfoot Toad). 

Of the 2,046 total species recorded, at least 34 of them appear to live only in the Alto Mayo landscape or Peru’s San Martin region, including the Andean saddle-back tamarin. To document so many species, scientists complemented traditional survey methods with technologies such as camera traps, bioacoustics sensors and environmental DNA (eDNA) collected from the water.

A Path for People and Nature

The Alto Mayo Landscape is a region of extraordinary biodiversity with a relatively high population density that has led to significant pressures, including deforestation and agricultural expansion. Conservation International has worked closely with Indigenous groups, such as the Awajún people, and local communities and governments to support sustainable livelihoods and agricultural practices that balance needs of people and nature in the region.

“We found that areas closer to cities and towns still support incredibly high biodiversity, including species found nowhere else,” said Larsen. “These findings underscore that even in areas heavily influenced by people, biodiversity can persist but only if ecosystems are managed sustainably.”

A Vision for the Future

Data from the expedition will guide plans to connect the Alto Mayo Protected Forest with the Cordillera Escalera Regional Conservation Area, forming an ecological corridor essential for species persistence. Additionally, the data collected will support a spatial management plan for the Alto Mayo Landscape, designed to conserve biodiversity, enhance agricultural sustainability and secure essential ecosystem services that local communities depend on ­– all while fostering a more resilient, interconnected region.

“This more comprehensive understanding of where species live helps us identify areas with the greatest potential for conserving or restoring biodiversity, as well as those best suited for sustainable activities like ecotourism, selective logging, agriculture and resource harvesting,” said Larsen.

Conservation International researchers were joined in the field by Peruvian scientists from Global Earth by and by local experts with extensive traditional knowledge from FERIAAM (the Indigenous Regional Federation of the Alto Mayo Awajun Communities). 

“This Rapid Assessment allows the Awajún to protect our culture, natural resources and our territory, as we have a deep connection with nature,” said Yulisa Tuwi, an Awajún woman who assisted with the research on reptiles and amphibians. “Being part of this research has allowed me to better understand how plants, animals and ecosystems interact with each other, and how this is part of our Awajún cosmovision.”

For more information about Conservation International’s 15 years of work in the Alto Mayo Landscape:

• A Peruvian Forest Was Vanishing. Coffee and Community Trust Saved It
• As Pandemic Pounded Peru, One Region Thrived on Coffee, Carbon
• The Alto Mayo Carbon Project: Supporting Forests and People in Peru

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About Conservation International: Conservation International protects nature for the benefit of humanity. Through science, policy, fieldwork and finance, we spotlight and secure the most important places in nature for the climate, for biodiversity and for people. With offices in 30 countries and projects in more than 100 countries, Conservation International partners with governments, companies, civil society, Indigenous peoples and local communities to help people and nature thrive together. Go to Conservation.org for more, and follow our work on Conservation News, Facebook, Twitter, TikTok, Instagram and YouTube.

About The Moore Center for Science: Moore Center for Science is a leader in developing research and tools that enable governments, communities, businesses and others to confront the most pressing issues of our time, including the climate and biodiversity crises.