Chemoreception, that includes both smell and taste, could play a significant role too. Reidenberg explains that baleen whales can possibly smell, while some whales have taste receptors on their tongues but that it"s not yet clear what exactly they are detecting. "They tend to swallow prey whole so maybe they are tasting the water to detect when they get close to prey or sensing salinity which may help them navigate," says Reidenberg. "It"s even possible that narwhals could sense salinity through the sensitive pores in their tusk – that could be a really important sense."