Scientists purposefully made mice sick to test how the creatures’ intestines—and the microbes they harbor—would react. They discovered details behind a remarkable relationship that, when working well, keeps both parties healthy.

While bats live in air and dolphins live in water, both use a biological form of sonar technology called echolocation to see with sound! The specifications in dolphin and bat biosonar systems are so many, so well-integrated, and so precise, could they really have developed at random in two completely different environments?

Physicists in California and Hawaii found evidence that solar wind performs curious chemistry on space dust to produce water, and they suggested that this discovery will help support a naturalistic origin of life on Earth or other planets. But how much help will it really bring?

Scientists age-dated a cache of stone-tipped throwing spears unearthed from Ethiopia's Gademotta Formation at 280,000 years old. This find appears to pierce the conventional story of human evolution—a narrative about modern man evolving from some pre-human type only 200,000 years ago. How will this date discrepancy be resolved?

Scientists recently ran experiments to determine what happens when excess nucleotides are present during DNA replication.¹ In normally functioning living things, each newly formed cell receives all the freshly minted DNA it needs. But DNA copying (replication) requires manufacturing a new chromosome based on the template of an existing one—a complicated task.