its a didital 1 that sticks to the glass with a sucker . the sucker is pretty strong , but they are only small at the moment , il bet my right arm it ends up floating when they are big enough to get their mouths over it
i think its probably just curiosity now that they are getting bolder , altho im sure that the real "fun" will begin in a couple of months when they are big and strong enough to do their " interior design"