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 penis dubbed "a real Moby Dick". The specimen is just the tip, as the entire organ, when intact, would have been about long and weighed about , well above average for even a blue whale. By comparison, an adult elephant's penis is the largest penis of any land animal at on average. Blue whale penis The blue whale has the largest penis in the animal kingdom. It is commonly cited as having an average penis length of to and a diameter of to . The reported average penis length varies but is usually mentioned to have an average length of .