Actually no, "over 8000" is what my source says. I looked again now and the individual article (not the list I used) says 10,000 native and 30,000 in total, so the list seems to need some updating. I'll look into it and change what needs to be changed.
Ok, I was hoping for some fantastical story about why signers in Norway and Madagascar use the same language, but according to Wikipedia they just have some signs in common and are not actually the same. I'm not sure why the Wikipedia page puts them together...