Why Elephants Cry is a fascinating frolic through the literature and evidence surrounding the use of unusual behavior of animals to measure and predict the environment. The role of animals, from the smallest ant to the biggest elephant, as predictors of environmental changes is framed around the climate crisis, which highlights the increasingly important part that animals will have to play in the future.

Renowned biologist Professor John T. Hancock collects anecdotal stories and myths along with scientific evidence, demonstrating that observation of animals can be of tangible use. He looks at the measurement of the air temperature using ants, crickets, and snakes, and goes on to assess the evidence that the observation of a wide range of animals can predict the weather or the imminent eruption of volcanoes and earthquakes. Evidence of animals being able to predict lunar and solar events, such as lunar cycles and the Northern Lights, is also considered.