10 Weirdly Human Animal Behaviours

6. Dolphins Sleep Talk... In Whale

A groups of dolphins in a French aquarium have been making waves recently.

The keepers noticed that they were making some strange noises, but only at night between the times of 12am and 1am.

The noises they were making were not like any known dolphin calls, and researchers soon realised that they may actually be whale calls.

It is thought that the dolphins were picking up these sounds from the aquarium's soundtrack of "vague ocean sounds" that contained a couple of minutes of whalesong. The dolphins were hearing this on repeat as it played throughout the day, and then reproducing the sounds at night.

In a study on the mysterious sound, volunteers were able to successfully distinguish between the dolphin and whale calls when the recordings were played back to them, so it looks like the keepers weren't just hearing things either.

For more spooky aquatic utterances, take a look at this beluga whale that has learnt to mimic human speech.