Blue whale hearts are the largest organs of their kind on the planet, weighing around 400 pounds and beating only a few times per minute when the colossal mammal dives deep underwater.

A closer look

Blue whale hearts are the largest organs of their kind on the planet, weighing around 400 pounds and beating only a few times per minute when the colossal mammal dives deep underwater. The arteries attached to this massive pump are so astonishingly wide that a fully grown human child could comfortably crawl through them, assuming you are okay with traumatizing a child for the sake of biological trivia. Because the whale is so gigantic, it takes a solid ten seconds for a single heartbeat to complete its rhythmic cycle. It is difficult to wrap your head around a biological engine that large quietly thudding in the dark abyss of the ocean. It really makes you evaluate the fragility of the human cardiovascular system, which tends to panic and rapidly palpitate at 120 beats per minute just because you had to walk up two flights of stairs or heard a weird noise in your apartment at midnight