When fed peanuts, red squirrels in Britain developed weaker bites — showing that food supplements to threatened animals could have unintended side effects.

Experts say clinical obesity is more than a high BMI and instead is a disease in which excess body fat harms tissues, organs or doing daily activities.

Amid doubts over a common decongestant, evidence suggests the placebo effect can still help people suffering from a cold.

For hundreds of millions of years, wildfires were directed solely by the weather, vegetation and terrain. But in the last century in the United States, people have sought to suppress even those ...