One day, a scientist named Micheal Long and his team discovered these creatures and brought them back to his lab
Maybe someone taught them?
How does their brain now how to "sing" in a duet?
Maybe they figured out how humans talk, and put it into song
Long soon discovered that the mice' brains know when to take turns singing, like when humans talk in a conversation.
Now, several generations in, the mice can be a bit wild. They can bite, but Long's students have held their hand out flat, had the mouse crawl up, and fed the mice with a dropper. After that, the mouse crawled back in his cage.