Lowest frequency hearing – animal

The humble pigeon is a remarkable bird indeed. The mysterious methods it uses for navigation, for which homing pigeons are most noted, have proved difficult for science to understand. However, during a pigeon race in 1977 from Nantes, France, back to England, homing pigeons' navigation was disrupted by the sonic boom from a Concorde transatlantic flight, giving scientists the first clue that extreme low-frequency sounds from the Earth (infrasound) was a primary tool in the birds' navigational capabilities. Using heart-rate monitoring, scientists have confirmed that pigeons hear frequencies as low as 0.5 Hz, with increasing sensitivity from 5 Hz upwards; three times better than even an elephant.