Animals

The physics of mixing water layers — an interplay of wind, climate and more — makes lakes work. When it stops, impacts can ripple across an ecosystem.

Despite their wide variety of sizes, niches and shapes, sharks scale geometrically, pointing to possible fundamental constraints on evolution.

An updated evolutionary model shows that living systems evolve in a split-and-hit-the-gas dynamic, where new lineages appear in sudden bursts rather than during a long marathon of gradual changes.

Richard Prum explains why he thinks feathers and vibrant traits in birds evolved not solely for survival, but also through aesthetic choice.

The effects of insufficient water are felt by every cell in the body, but it’s the brain that manifests our experience of thirst.

Scientists reconstructed 500 million years of evolutionary history to reveal which came first: colorful signals or the color vision needed to see them.

Slight changes in the number, shape, efficiency and interconnectedness of organelles in the cells of flight muscles provide extra energy for birds’ continent-spanning feats.

Complex neural pathways likely arose independently in birds and mammals, suggesting that vertebrates evolved intelligence multiple times.

Rare and powerful compounds, known as keystone molecules, can build a web of invisible interactions among species.