Okay thanks . He recently changed place but he did it before he moved .Changes or something unusual or new can set this type of alarm behavior off. It could be something new or that has been changed in their environment, or an odd sound like a bug or mouse skittering around, or an unusual sound outside. It could be odd smells like cleaners, scented products, cooking smells, the smell of a dog, cat, or predator. So try and think through or listen for anything that this thumping behavior could be connected to.