Animals with the best hearing in the world

Known for their large ears, it's not surprising that elephants have great hearing. They are particularly good at detecting low-frequency sounds-they can hear frequencies as low as 17 Hz, while humans can hear as low as 20 Hz. However, their high-frequency hearing is less impressive. They can only hear up to 12,000 Hz frequencies, while humans can hear up to 20,000 Hz. There is a correlation between the size of the space between mammals' ears and their ability to hear high frequencies. Bats, for example, can hear much higher frequencies because their ears are closer together.

Elephants' ears are multipurpose-not only are they used for hearing, but they are also important for thermoregulation. Their ears hold large blood vessels, and when blood circulates out from the body and into the ears, it cools down. This cooler blood is then spread through the rest of the elephant's circulatory system.

Whales

The biggest animals in the world also have some of the best hearing. There are two different types of whales -toothed whales, which are hunters, and baleen whales, which are filter feeders-and they hear differently. Toothed whales rely on echolocation to catch their prey. They make high-pitched, ultra-sonic sounds using their noses, which echo back to them. In this way, they can 'see' using high-frequency sounds. An example of a toothed whale is the beluga.

Baleen whales can instead emit and hear very low-frequency, infrasonic sounds. These sounds can travel thousands of kilometres-across entire ocean basins. They are used for communication with other whales, not for hunting. An example of a baleen whale is the North Atlantic right whale.

Because they rely on their hearing to survive, ocean noise pollution poses a huge threat to whales. IFAW is working to reduce ocean noise through our Blue Speeds campaign.