From sea lions to killer whales (and even polar bears), there's a great diversity of marine mammals living across Earth's oceans. At Live Science, we guide you through the underwater worlds of our marine relatives with the latest news, features and articles, so whether our expert writers and editors are explaining why deep-diving mammals don't black out or reporting on a gray whale breaking the mammal migration record, you'll always have interesting marine mammal facts to read.
Latest about Marine Mammals
Male humpback whale crossed 3 oceans for sex, inadvertently breaking distance record for species
A male humpback whale swam 8,106 miles (13,046 km) from the Pacific to the Indian Ocean, mingling with other whale populations and potentially having sex with them along the way.
Orca gang develops brutal hunting strategy to take on the world's largest shark — 'This is a fascinating behaviour'
The orca attacks appear to be led by a large adult male, suggesting that he may be leading the charge on this predatory behavior.
Orcas start wearing dead salmon hats again after ditching the trend for 37 years
Orcas off the coast of Washington State are balancing dead fish on their heads like it's the 1980s, but researchers still aren't sure why they do it.
Orca quiz: Will you sink or swim?
Have a go at our killer whale quiz and find out if you'll make a big splash or a major fail.
Dolphin in the Baltic Sea has been talking to himself — and researchers think it's a sign he's lonely
A solitary dolphin in the Baltic Sea has been recorded talking to himself, leading researchers to wonder whether he's lonely and calling out for friends.
Mysterious sound coming from the Mariana Trench has finally been explained
A new study has revealed the exact origin of the Pacific Ocean's mysterious "biotwang" noises, which were first detected by underwater surveys near the Mariana Trench in 2014.
Sexually frustrated dolphin behind spate of attacks on humans off Japan
A stock image of an Indo-Pacific dolphin swimming (not the individual responsible for the recent attacks).
Boat-ramming orcas may be using yachts as target practice toys, scientists suggest
Orcas off the coasts of Spain and Portugal may be using boats as targets to practice hunting their favorite food, Atlantic bluefin tuna.
