Dolphin Killer whales have the second largest brain mass of any animal on earth, next to the sperm whale. The brain to body mass ratio in some is second only to humans. Self-awareness is seen, by some, to be a sign of highly developed, abstract thinking. Self-awareness, though not well-defined scientifically, is believed to be the precursor to more advanced processes like meta-cognitive reasoning (thinking about thinking) that are typical of humans. Research in this field has suggested that cetaceans, among others, possess self-awareness. The most widely used test for self-awareness in animals is the mirror test in which a mirror
Blue whale to exist in real life, due to metabolic and energy constraints. Due to its large size, several organs of the blue whale are the largest in the animal kingdom. A blue whale's tongue weighs around and, when fully expanded, its mouth is large enough to hold up to of food and water. Despite the size of its mouth, the dimensions of its throat are such that a blue whale cannot swallow an object wider than a beach ball. The heart of an average sized blue whale weighs and is the largest known in any animal. During the first seven months