Learning from the heaviest ancient whale

A representation of the recovered fossils (A, source: ref. 1,2) and morphological reconstruction of Perucetus colossus (B, credit: Alberto Gennari) and the inferred position of Basilosaurids (red text) in the cetacean phylogeny (C, source: ref. 3)

A groundbreaking study published in Nature by Bianucci et al. has reported the discovery of a new basilosaurid species, Perucetus colossus (Figure 1). The incomplete fossil skeleton found in Peru is around 39 million years old. This ancient whale challenges the long-held belief that the blue whale represents the largest known animal to have ever lived on Earth. P. colossus is estimated to have had a body mass between 85 and 340 tons, with an average of 180 tons.1 In comparison, extant blue whales have an estimated body mass of 100–150 tons.