Way more than 500. Some estimates are around 3,500, some around 3,800, and some over 4,000. They come in different sizes from a tiny tree frog the size of your thumbnail to the humongous goliath frog of Cameroon that can grow over a foot long and weigh almost 8 pounds. Good guess but not for frogs. Some animals, like the tufted puffin, will turn brightly colored in the springtime to attract a mate then turn darker in the winter to avoid predators.
Frogs are colorful year-round.
Frogs use their voices to find mates. You got it. Or rather, frogs have got it. Poison, that is. When predators try to eat one of these frogs, they taste the poison and spit them out.