A lot of my pets are "exploring an island" and i cannot interact with them.They have been stuck like that for more than a year! How do i get them out?

Your pets never left the island last time you were exploring. So technically they are still busy.

Click on one of your pets that is exploring an island to make this your active pet. Then click on the explore tab to go to the island your pet is on.

You will have to move your pet to the portal on the island. When your pet is on top of the portal the image of the portal on the control panel will have a light on it. If you click this your pet will exit the island and become "active" again. I hope this has helped. Let me know if you have more questions or need clarification!