Is a class of nocturnal mammals, belonging to the hedgehog family, widely distributed in Europe, Asia and Africa. The most striking feature of their rounded bodies is that their surfaces are covered with specialized spines of keratinized hair that stand up when they feel threatened, helping them defend themselves against predators. The eyes are small and divine, the nose is long, and the limbs are short but powerful, suitable for digging and climbing. The lifespan is about 3 to 5 years in the wild, and may be longer in captivity. It feeds mainly on the eggs of insects, worms, small mammals, and birds, and sometimes on plant foods. The spines are soft at birth, but they soon harden.

It is a small wading bird that lives in moist forests in eastern North America. Belonging to the sandpiper family, it is known for its unique mating flight. With a round body shape, short legs, and a straight beak that appears particularly long in proportion to the body, it is very suitable for exploring food in soil, especially earthworms. The eyes are large and round, located at a higher position on the head, providing a broad field of view that allows for almost a 360 degree view of the surrounding environment. In spring, male American sandpipers perform special aerial courtship shows at dusk or dawn, making the sound of "pee" and flying into the air in a spiral pattern to showcase their flying skills.