Humans are the slowest-maturing mammals on Earth. No other species invests more time, energy, and social infrastructure into raising its young. Why do humans grow so slowly compared to other animals?

Research into human-animal chimeras could have a therapeutic payoff, but the work brings up thorny ethical questions.

In the movie Hoppers, scientists “hop” human consciousness into animal-like robots to talk to other species. We asked the experts their thoughts on how conceivable the plot is. Some scientists believe ...