like theme parks, airports are not "fun". The team then pivoted to a zoo building game, and quickly began research on animal care and behavior, sending artists, animators and developers to zoos in and around the Boston area, as well as flying a team out to the San Francisco Zoo. The team learned how zoos work in order to figure out where they were allowed to take creative liberties, citing that during the development for the Marine Mania expansion, the team gave dolphins the ability to do tricks that were not completely realistic because they thought it was more fun. The development team also carefully tried to strike a balance between teaching players about conservation and entertainment, citing the educational efforts put forth in real zoos. Expansion packs Zoo Tycoon was created in the wake of the success of the 1999 Hasbro Interactive game RollerCoaster Tycoon, which sold well for many years. Zoo Tycoon did well enough for Microsoft and Blue Fang Games to release two expansion packs: Dinosaur Digs, which added prehistoric-themed items and animals including mythical creatures, and Marine Mania, which added aquatic-themed items and animals. Eventually, Microsoft bundled the expansion packs with Zoo Tycoon to create Zoo Tycoon Complete Collection as Hasbro had done for RollerCoaster Tycoon. This had the functionality of both expansion packs and bonus content. Dinosaur Digs Released on May 19, 2002, Dinosaur Digs includes 20 new prehistoric animals to choose from including mammoths, saber-toothed cats, and varied dinosaurs as well as prehistoric-themed items and buildings. In addition, new types of electrical fences to accommodate the animals and prehistoric foliage have been introduced. As in the previous game, more extinct animals, foliage and better care for dinosaurs can be researched. Each dinosaur is adopted as an egg. The game introduces a new staff member, the scientist, to care for the egg and, once it hatches, the dinosaur itself. Despite the fact that the player can purchase electrified fences to keep dinosaurs contained in exhibits, it is still possible for them to escape. If one does escape, the player will have to hire a dinosaur recovery team to find and tranquilize it so that it can be returned to its exhibit. Marine Mania The second expansion pack to the game wherein players can create and manage underwater exhibits or merge aquatic tanks with traditional land habitats was released on October 17, 2002. Interactive tutorials and