Hormones are responsible for a lot of important things inside the body, like regulating digestion, sleep patterns, and mood. They also are at the root of a lot of behavior. As we said earlier, finding a mate is what drives a great deal of animal behavior. Hormones prepare an animal for sex and for nurturing offspring, and they also make you drool over Taylor Swift, Ryan Gosling, or whomever you might find attractive.
Hormones dictate pretty much every part of a teenager’s life—as soon as puberty hits, those hormones say, "go find a mate, go find a mate!" Whether you realize it or not, those hormones are telling you to look your best, impress the other sex, show off your muscles/beauty, and drive recklessly.
Hormones also affect other animals’ lives. Have you ever slept in the woods and heard frogs ribbiting all night? If not, listen to bull frogs here. They are not singing you a lullaby; they are calling for mates. Frog mating calls happen because of hormones called androgens, which are male sex hormones. Testosterone is the most well-known androgen, and is also responsible for a lot of male physiology. In humans, androgens are responsible for the development of male sex organs and secondary sex characteristics such as body hair, deep voice, and muscle development.
Frogs are not the only ones who make mating calls because of testosterone—birds do, too. Male birds experience an increase in testosterone concentrations in the spring, when days get longer and food becomes more abundant. This is the perfect mating season, so male birds start to sing. As testosterone levels increase, males sing more and may have more complex songs, hoping to attract a female ready to mate.