Readers are first introduced to yellow spotted lizards in the very first chapter of the book. The narrator is giving readers setting details, and things are not looking pretty. There is no lake at Camp Green Lake. It is just a dry, parched wasteland filled with creatures just as harsh as the environment itself. Readers are told about the standard scorpions and rattlesnakes, and the narrator lets us know that being bitten by one of them is bad, but it ultimately means a few days' rest for the victim. Bites from snakes and stings from scorpions are not the worst thing. The worst thing is a bite from a yellow spotted lizard, because it guarantees a slow and painful death.
I believe that this question is asking about details that chapter 8 provides to the reader. Chapter 8 is a short chapter, and its focus is entirely on giving readers specific details about the yellow spotted lizards. A yellow spotted lizard has exactly eleven spots, but those spots are somewhat difficult to see against its yellow-green body. The lizards can range in size from six to ten inches in overall length. The lizards have yellow eyes; however, everybody describes the eyes as being red. This is because the skin around the eyes is red. They have black teeth, a white tongue, and powerful legs. Their diet consists of insects, small animals, cactus needles, and the shells of sunflower seeds.