Ultimately, the reasons for breaching are unknown; however, there is evidence to support a range of hypotheses. Whales are more likely to breach when they are in groups, suggesting that it is a non-verbal signal to other group members during social behaviour. Scientists have called this theory "honest signalling". The immense cloud of bubbles and underwater disturbance following a breach cannot be faked; neighbours then know a breach has taken place. A single breach costs a whale only about 0.075% of its total daily energy intake, but a long series of breaches may add up to a significant energy expenditure. A breach is therefore a sign that the animal is physically fit enough to afford energy for this acrobatic display, hence it could be used for ascertaining dominance, courting or warning of danger. It is also possible that the loud "smack" upon re-entering is useful for stunning or scaring prey, similar to lobtailing. As breaching is often seen in rough seas it is possible that a breach allows the whale to breathe in air that is not close to the surface and full of spray, or that they use breaching to communicate when the noise of the ocean would mask acoustic signals. Another widely accepted possible reason is to dislodge parasites from the skin. The behaviour may also be more simply a form of play.