Doctor Who can function with two hearts, but can non-Time Lords do the same? Greg Foot finds out. Being a Gallifreyan, Doctor Who has a binary vascular system, where the blood vessels lead to two ...

A 16-year-old girl who survived a dire heart condition as an infant, a transplant surgery that gave her two hearts and cancer has now made a remarkable recover and is living cancer-free with her ...

An octopus has one main, systemic heart that pumps blood to the whole of its body. But it also has two additional hearts, responsible for pumping blood over each of its gills. For more videos ...