Our dogs and cats provide all kinds of benefits. They improve physical health, reduce stress and can fend off loneliness.

Research shows that interacting with pets can lower blood pressure. Dogs need walks and playtime, which helps people stay active. And both dogs and cats can form deep bonds with humans. Basically, the enrich our lives.

“There’s a whole body of literature supporting that,” said Pieter De Frenne, a bioscience engineer at Ghent University in Belgium.

Yet for all the good, pets come with environmental costs. Cats and dogs eat a lot of meat, for example. They also kill wildlife.