Complex behaviour such as regional accents and cultural food preferences in whales and dolphins seems to be linked to brain size.
More than 400 whales have died on a beach in New Zealand.
As the vaquita porpoise heads towards extinction, new management measures in Mexico still may have missed the point -- affecting not one but two critically endangered marine species.
Globally, a quarter of whale and dolphin species are endangered. Though South African dolphin populations are generally in good heath, the humpback dolphin is cause for concern.