Trying to count sloths in a rainforest is quite hard: they move slowly, blend perfectly with the leaves, and spend their days tucked high in the canopy. But now, technology is giving conservationists and researchers a powerful new ally: drones that can see heat.

Vanderhoeven, E.A., Florida, M., Cliffe, R.N., Guzmán, J., Notarnicola, J. and Kartzinel, T.R., 2025. Host specificity of gastrointestinal parasites in free-ranging sloths from Costa Rica. PeerJ, 13, p.e19408.