chunk: Sattler assists the park's game warden, Robert Muldoon, in a search for survivors, but they only find an injured Malcolm before the Tyrannosaurus returns. Grant, Tim, and Lex spend the night in a tree, and befriend a Brachiosaurus. Later, they discover the broken shells of dinosaur eggs. Grant concludes that the dinosaurs have been breeding, which occurred because of their frog DNAâWest African bullfrogs can change their sex in a single-sex environment, allowing the dinosaurs to do so as well, proving Malcolm right.