Ten creatures show off their mental powers in a bid for sapient supremacy. Who will win? As in Battle of the Butts (2021), also illustrated by Creighton-Pester, Rish invites readers to judge. After wowing them with some head-exploding research, she asks them to decide where each animal belongs on a five-stage scale, from "Basic Brain" to "Incredible Intelligence." That won't be an easy task because the exploits--most of which were observed under controlled conditions--range from African grey parrots naming colors and counting up to eight, rats learning how to drive little cars, and a border collie who could identify more than a thousand toys by name to pigs that could spell words like (ironically or otherwise) ham, chimps taught to play Rock-Paper-Scissors, and ravens who can add and compare sums. Humans with an exaggerated opinion of their own mental capacities may be taken down a peg or two by elephants ("Can you identify each of your friends and family members by the sound of their voice? How about by the smell of their pee?"). Smiling animals strutting their stuff in Creighton-Pester's cartoon illustrations further lighten the informational load, and to counter any suspicions that some of it might be fabricated, the author points to a source list on her website (not there at time of review). So who will win the Coolest Cranium cup? It's a head-scratcher. (This book was reviewed digitally.) A no-brainer stocked with full measures of breezy scientific gosh-wow. (glossary) (Informational picture book. 6-8) Copyright (c) Kirkus Reviews, used with permission.