The five primary tastes are sweet, bitter, umami (savoury), sour and salty, which are detected by receptors on tongue cells. Flavours are typically released by chewing, so animals that swallow their food whole, may taste them less vividly. Yet, there’s more to it. In 2014, researchers showed that 15 species of food-gulping cetaceans, including minke whales and bottlenose dolphins, lack functional genes for sweet, bitter, umami and sour taste receptors.
They can’t taste these flavours, but they can still taste salt. The presence of salt receptors indicates they must play an important role, such as regulating sodium levels or blood pressure.