Those who explore the waters of the Amazon basin occasionally hear a forceful snort, the sound that a pink river dolphin or boto makes when it surfaces to exhale. Visitors sometimes catch a glimpse of a pinkish, rounded forehead or small dorsal fin just above the surface. That’s likely all they’ll get, though. Not only are these freshwater dolphins relatively shy, but their numbers have also drastically declined in recent years.
Humpback whales' songs carry thousands of miles, while a sperm whale scans the ocean depths with a sonar laser beam louder than a thunderclap. "Voices of the Sea" reveals a surprising underwater world where sound takes the place of sight.
In some respects the brains of whales and dolphins are more complex than ours. Whales and dolphins work co-operatively, show empathy and are self-aware. Find out how clever, and how much like us, whales and dolphins might be.
Check out swarm intelligence, essentially a living embodiment of social media in the natural world.
The seasonal migration of billions of sardines is a stunning example of a swarm's defensive collective thinking.
Lichen survive outer space (and what that might say about how life on earth began), genetic research suggests dolphins are second in intelligence to modern humans, new dinosaur bird ancestor discovered in Argentina, and more of this week's top nature stories.
Although they're referred to as songs, male humpbacks technically are humming when they create their famous underwater compositions.