Sola Canstick Ball

Q: What kind of glue holds the ball together? There is a post on Facebook about other sola balls and in an effort to be proactive I am gathering information about my toy parts. I recently ordered some of these for my Halloween toys. I wanted to know what glue holds them together because there has to be some thing holding it together. I just wanted to know whether it is natural or not. I did notice a string in them but also seems to be glued. Thank you so much!