The mythical unicorn may have been inspired in part by real-life creatures—members of the extinct genus Elasmotherium, comprising single-horned, giant rhinoceroses that roamed what is now Siberia and southern Russia during the Pleistocene ice age, which began 1.8 million years ago. Having some of the attributes of horses, they were herbivorous like most other rhinoceroses and had molar teeth that never stopped growing. How long were their supposedly enormous horns? Discuss