Our world is filled with fascinating, smart, and creative mammals and related species. Elephants, whales, capybaras, cats and dogs, to name a few of the most playful mammals. The small Kangaroo Island Echidna is one of the oldest mammals and the most distant human relative. It is only 22 pounds and looks like a hedgehog but is totally unrelated. The echidna may have shared space with the dinosaurs for 110 million years. The echidna lays an egg and quickly scoops it up into a pouch where it hatches and attaches to a patch, a precursor for the breast. The rarest mammal is the endangered vaquita, a shy member of the porpoise family. It is the smallest known cetacean and less than 20 remain. They are about 5 feet long and are found only in the upper reaches of the Northern Gulf of California where they are uniquely adapted to these warmer waters.