Stories by Jennifer Welsh

Coyotes are overtaking the red fox, which feeds on small mammals such as mice, shrews and chipmunks, animals that, like deer, can play host to the Lyme-disease-carrying ticks

A blood test based on 11 genetic markers could make early-onset diagnosis easier and possibly relieve the stigma of depression

Chimpanzee nest-building habits could provide clues to what drove humans from the trees

Older people slow down to avoid making errors, but there may not be a uniform decline in all cognitive processes

Laughter with friends releases endorphins, the brain's "feel-good" chemicals

A new study finds that levels of testosterone, the "macho" sex hormone, drop in new fathers