Neanderthals (Homo neanderthalensis), are the human species that has attracted the most attention as our closest evolutionary relatives. The first fossils related to Neanderthals weren’t recognized as such until 1863, although they were discovered decades earlier. The ongoing intrigue should come as no surprise because, for a long time, Neanderthals were the model for the missing link between our own species, Homo sapiens, and the first apelike pre-human ancestors—but then they disappeared. This is the story of an extinction.

A new study of Neanderthal ear bones reveals that they went through a population bottleneck around 110,000 years ago. may have been headed toward their demise much earlier than experts previously thought, new research suggests. In the study, published online Feb. 20 in the journal , researchers discovered that around 110,000 years ago, our closest human relatives experienced a "population bottleneck" that decimated their genetic diversity. A occurs when there is a sudden reduction in genetic variation within a species. Bottlenecks in a species can be brought on by a...