Listen to the oldest known recording of a whale song

This incredible audio, which has just been discovered in an archive collection, might well be the oldest ever known recording of a whale song.

It was recorded on 7 March 1949 by researchers aboard a ship near Bermuda, a group of islands in the North Atlantic Ocean.

For the next 75 years or so, the recording sat in storage, until a team from the Woods Hole Oceanographic Institution (WHOI) found and identified the sound.

It's thought to be the song of a humpback whale, and it's amazing how clear it still sounds today.

Laela Sayigh, a senior research specialist at WHOI, said that the recording "can provide insight into how humpback whale sounds have changed over time".

The story starts in 1949, when researchers on ships were performing lots of experiments to try and listen to the ocean, including working on things like sonar - which is something that whales themselves use to navigate the seas.

At this time, scientists and sailors were making use of different equipment, including a device called a Gray Audograph.

This machine was originally made for recording speech in an office - like an old fashioned version of a voice note - and prints the sound onto a thin plastic disc.

And that's exactly what this 1949 whale song was recorded onto.

These discs have survived much better than other recording formats like tapes would have, meaning the sounds are still clear today.

Ashley Jester, who is Director of Research Data and Library Services at Woods Hole Oceanographic Institution, is thankful that the researchers in the past were so curious about the underwater sounds.

She said: "They even made time to make recordings where they weren't making any noise from their ships on purpose, just to hear as much as they could."

As this was as possibly the earliest whale recording ever made, the researchers might not even have known what they were listening to.

Ashley adds: "They just knew that these were sounds, but later scientists were able to make the connection directly between the sounds being created and the species that they were observing."

Scientists say that there are a few reasons why whales might produce sounds.

It's extremely dark underwater and so cetaceans - dolphins and whales - don't use their eyes to find their way.

Scientists think that whales give out a clicking sound so that they can listen to the echoes coming back to help them work out distances and shapes.

Different sounds, like whistles and calls, could be how whales communicate with their pod, which is the social group that they travel in.

It's thought that whales may also sing their longer songs to help them find a partner, but we still don't know for certain why - or even what it is - they're singing.