How do you get a cub pet in Sims2 castaway stories?

Get both animals to like each other until their relationship is up to about 100, then click on one of the animals you want to have a baby with. Choose the option 'try for puppy with..' then choose the other pets name from the menu. Make sure you have the friendly predator pet shelter on the lot, and if their relationship is high enough, they will go inside it and have babies! You will need to wait a few days, and the puppies will come!