Brain size area in women, corresponding to spatial versus language specializations. Small studies have attempted to link brain volume with functional measures such as P300 auditory evoked potentials but finding no association. Studies attempting to related sibling differences in IQ to differences in brain volume are hampered by relatively small sample sizes and the noisy nature of such difference scores, yielding weak evidence for cross-trait cross-sib correlations. The largest brain is that of the sperm whale, weighing about , and killer whales, weighing about . An elephant's brain weighs just over and a bottlenose dolphin's . Brain size tends to vary according
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