The enzymes that act inside the small intestine are amylase, protease, and lipase. Amylase acts on starch and breaks it down into small carbohydrate molecules. Protease acts on proteins and breaks them down into amino acids. Lipase breaks down dietary fats into smaller molecules called fatty acids and glycerol.
Sandhill Cranes mate for life, choosing their partners based on dancing displays. Displaying birds stretch their wings, pump their heads, bow, and leap into the air. Although each female usually lays two eggs, only one nestling typically survives to fledge.
Swans often do mate for life but it's less romantic than you'd think. Reputation: Swans' love for their partners is so deep they mate for life. They are creatures of myth that only sing when they are dying. Also, paradoxically for such paragons of elegance, they are vicious blighters that can break your arm with their wings. Reality: Swans often do stay with their partners for life.