Both interviewees and interviewers engage in strategies to reduce uncertainty. Rose was one of the most candid interviewees in the film. Hampton said that Simmons would call prospective interviewees late into the night. The film juxtaposes the childhood memories of interviewees with archival footage. The interviewees in these scenes are sometimes obscured or distinguished by technicians watching the recording. These animals are always portrayed by the same interviewees to maintain consistency throughout the series. Actor Colin Farrell was among the initial interviewees. Nearly half of the interviewees stated that family members of theirs had been killed. Photographs and additional details about the interviewees can be seen on the PBS website. The sexual orientation items are presented only to interviewees over age 18. Purvis had the reputation of using very tough methods against recalcitrant interviewees. In 2008, approximately 20% of the interviewees were refused citizenship. Most of the interviewees did not fear death; some would welcome it. More than two-thirds of the interviewees agree to renewable power plants close to their homes. Hirschberg has been the subject of ire from several of her interviewees.