A female kangaroo is called a "flyer," while a male kangaroo is called a "boomer," and a baby kangaroo a "joey," according to Ferris State University. There are more than 40 species of kangaroos, which are classified as marsupials.
The largest marsupial is the red kangaroo, which can jump more than 10 feet high, weighs more than 200 pounds and can hop 30 to 40 miles per hour. The red kangaroo's gestation period is 30 days. Their babies weigh approximately 1 gram when born, staying in the mother's pouch for about 235 days, according to Ferris State University. Smaller kangaroos are called "wallabies." The kangaroo got its name by mistake, when an explorer asked an Aborigine what the animal was called. The Aborigine answered "kangaroo," meaning "I don't understand." The explorer thought that "kangaroo" was the name of the animal.