"Revise the book cover to replace the large lion and small lion cub with a majestic large rhinoceros and a smaller rhinoceros calf. Position them atop a hill in the savanna, silhouetted against a stunning sunset. The adult rhinoceros should exude strength and wisdom, while the calf radiates curiosity and innocence. The backdrop features the golden hues of the savanna, with acacia trees dotting the horizon and the vibrant colors of the sunset painting the sky. The composition should evoke a warm, emotional connection between the two rhinoceroses, emphasizing their bond and the beauty of their natural environment."