Hint: it’s not the blue whale! The award goes to another underwater behemoth, the sperm whale. Its deafening clicks, used for communication, have been measured at a whopping 230 decibels (dB) – louder than the eruption of Krakatoa in 1883. However, the blasts only last for a measly 100 microseconds, while blue whale songs (around 188dB) can be as long as 30 seconds. The title of loudest land animal is even more hotly contested, with elephants (103dB), hyenas (112dB), howler monkeys (128dB) and bulldog bats (140dB) all vying for the crown.