An animal is an multicellular eukaryotic organism from the kingdom Animalia. All life on earth aside from plants and algae are animals including humans.
Nettie Stevens and Edmund Beecher Wilson independently discovered the chromosomal XY sex-determination system (that males have XY and females have XX sex chromosomes).
An Albatross can fly around the world without landing, glide hundreds of miles at a time without flapping its wings (which span up to 12 feet), and travel at speeds of over 50 Mph.
Water bears (tardigrades) are the only known animals to survive the vacuum of space. Water bears are extremophiles, meaning that they can survive extreme conditions (like high temperatures, and high pressure).