Menarche. The average age of menarche, or first menstruation, in the United States is 12.88 years for Caucasian girls and 12.16 years for African American girls.A popular misconception is that menarche marks the beginning of puberty; in reality, menarche occurs later in puberty.enarche. The average age of menarche, or first menstruation, in the United States is 12.88 years for Caucasian girls and 12.16 years for African American girls.
Quick Answer. Roadrunners eat insects, lizards, scorpions, small birds, rodents and snakes, including rattlesnakes. During the winter months when its preferred food is scarce, the roadrunner may supplement its diet with fruits, seeds and other vegetable matter. Continue Reading.
Greater Roadrunner. A bird born to run, the Greater Roadrunner can outrace a human, kill a rattlesnake, and thrive in the harsh landscapes of the Desert Southwest. Roadrunners reach two feet from sturdy bill to white tail tip, with a bushy blue-black crest and mottled plumage that blends well with dusty shrubs.