Humans have long observed animals for advanced warnings of danger. What can they tell us about the growing threat of contagion in the age of climate change?

Diseases today reveal our close ties to animals. Viruses leap from bats to camels to humans. Cats catch the flu, and tourists pass tuberculosis to elephants. In recent years, however, something has changed. Exploitation of the environment is causing more diseases to jump species than ever before — a threat to life that rivals climate change. The science is clear: the cause of this great acceleration is us.

In Sentinels, Michael Dulaney takes readers from southern China to the Andes, from the Arctic to Australia, to tell the gripping stories of the people and animals at the forefront of this enormous change. Dulaney joins ecologists tracking flying foxes through Australia’s eastern forests, and frog hunters netting endangered species on Indonesian mountains. Along the way, we meet lemmings that resist global warming, coastal seals with bird flu, and genetically engineered disease-proof pigs.