First record of sloths using thermal drones

First Record of Sloths Using Drones and Thermal Cameras

Drones are revolutionizing the way scientists collect data, especially in the study of biodiversity and conservation. The use of drones equipped with a range of sensors, including thermal cameras, can help identify species and track individual animals, making it easier to study and protect them. Recently published research by scientists in Brazil, called Every flight is a surprise: first records of the southern maned three-toed sloth through drones shows the first record of sloths using a drone with a thermal camera.


Drones: A Key Tool for Biodiversity Research

The worldwide threat to species and their habitats has necessitated the development of emerging technologies that can improve the efficiency of conservation strategies. Drones, also referred to as unmanned aerial vehicles (UAVs), are becoming increasingly popular in scientific research, with their ability to cover large areas and provide high-quality, reliable data. With a range of sensors, including RGB, multispectral, hyperspectral, LiDAR, and thermal, drones have been used to identify new areas of species occurrence, assess the density or distribution of a species, and monitor changes in land cover.

Sloths, Cryptic and Arboreal Animals

Sloths are difficult to identify and track, they have a range of morphological and behavioral traits that allow them to live high up in the forest canopy, making them difficult to detect with ground surveys. Sloths have low detection rates in forested areas, making it challenging to study them effectively.


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Individuals of the maned sloth identified via drone thermal images (the black and white images) and images from visual wavelengths (color images). Numbers indicate the order in which the individuals were found. Credit: Paloma Santos et al.


Drones with RGB sensors can obtain data from animals in more open environments without camouflage, but sloths are well-camouflaged in the canopy, making them almost impossible to detect in normal flight with an RGB sensor. Thermal cameras, which detect heat emissions from individuals’ bodies, have been found to be a valuable tool for collecting data from some arboreal mammals.

Drones and Thermal Cameras and Sloth Research

Paloma Marques Santos and her team, the authors of the paper, used a drone equipped with a thermal camera to observe sloths in the Brazilian Atlantic Forest. The drone captured the thermal responses of four individuals of Maned sloths, which were all resting in the forest canopy. The thermal infrared images captured the thermal signature of sloths well enough to be identified by the researchers.


thermal drone image 1
Location of maned sloths recorded by drone in Augusto Ruschi Biological Reserve, Santa Teresa/ES, Brazil. The first two individuals were detected on May 14, 2022 (A), and another two individuals were detected on May 15, 2022 (B). Credit Paloma Santos et al.

Implications for Sloth Research

The use of drones equipped with thermal cameras provides a breakthrough for sloth research, as they can now be observed in their natural habitat with greater ease and efficiency. This technology can help researchers identify and track sloths and obtain data on their behavior, movement patterns, and ecological requirements. Such data is critical to understanding the conservation needs of sloths and developing effective conservation strategies.

The Sloth Conservation Foundation is launching a new project that will use thermal drone technology to count sloths in the South Caribbean region of Costa Rica. The project is a complement to The Great Sloth Census and will involve trained pilots flying the drone (DJI Mavic 2 Enterprise) to collect data on sloth populations. This new technology is exciting news for sloth conservationists who have long awaited a more efficient and effective method of monitoring sloth populations.

However, the drone’s batteries only last for about 30 minutes, which means that for a five to six-hour session in the jungle, meaning wewill need around 10 batteries, at a cost of $190. If you would like to contribute to this project, you can make a donation or check their wish list to see how you can help.

Special Thanks to Fabiano Melo and his colleagues in Brazil!


-Cecilia Pamich