Why would penguins, which are aquatic birds that live in polar regions, be unable to survive in a desert environment?

Because penguins need cold here look at it like this a fish lives in water why can't it live on land because it can't walk and can't breath so it would die like we can't live under water penguins can't live in a desert because penguins eat fish there are no fish in the desert and penguins live in ice bergs and enjoy swimming and sliding on there belly on ice threres no ice in the desert so therefor they would die no food because they eat fish no home and no habitat and there are a lot of snakes and stuff that would eat the penguins