As you certainly know, even young children are fascinated with fantasy. Because of their peculiar form, pictures of dinosaurs easily become fantastic things for children and, as such, are a prefered target of children's imagination and fantasy.
Yes Children minds are innocent Curious and Investigative so they like to know some thing which is extinct. Dinosaurs are extinct species and it is history so children want to learn. Regards
Experts of Sandplay/tray therapy have proposed an alternative developmental model where they have explanation regarding children's interest with animals.