From Webkinz Insider Wiki
|Main Role: Runs the Souvenir Shack at Vacation Island.|
Sheldon runs the Souvenir Shack that you visit when you go on a vacation to the Vacation Island. He says that he saves the money earned for his own vacation he is going to take. Be sure to visit him every vacation. He has different items that you may choose from, and they change from vacation to vacation. However, you may only buy a maximum of three. He ran for the Webkinz Votes 2014 election but did not win.
There are a few Sheldon items in Webkinz World:
The first time a new Webkinz World member visits the Vacation Island and buys a souvenir from Sheldon. the member will receive a request to become friends with Sheldon Turtle. Even if they select "no", Webkinz members can later send a friend request to "Sheldon Turtle" to invite him to be their friend. 
Players who send a Webkinz World letter or package to Sheldon will occasionally get a letter or even a gift in return from him. More information about the Webkinz Host Friends gifts can be found here ==> Webkinz Host Friends