Why do carp jump out the water?

<!-- s:?: --><img src="{SMILIES_PATH}/icon_question.gif" alt=":" title="Question" /><!-- s:?: --> <!-- s:?: --><img src="{SMILIES_PATH}/icon_question.gif" alt=":" title="Question" /><!-- s:?: --> <!-- s:?: --><img src="{SMILIES_PATH}/icon_question.gif" alt=":" title="Question" /><!-- s:?: --> <!-- s:?: --><img src="{SMILIES_PATH}/icon_question.gif" alt=":" title="Question" /><!-- s:?: --> <!-- s:?: --><img src="{SMILIES_PATH}/icon_question.gif" alt=":" title="Question" /><!-- s:?: -->
Is there any reason behind this? Sometimes they roll other times they jump like dolphins. Can someone please explain <!-- s:?: --><img src="{SMILIES_PATH}/icon_question.gif" alt=":" title="Question" /><!-- s:?: --> <!-- s:?: --><img src="{SMILIES_PATH}/icon_question.gif" alt=":" title="Question" /><!-- s:?: --> <!-- s:?: --><img src="{SMILIES_PATH}/icon_question.gif" alt=":" title="Question" /><!-- s:?: --> <!-- s:?: --><img src="{SMILIES_PATH}/icon_question.gif" alt=":" title="Question" /><!-- s:?: --> <!-- s:?: --><img src="{SMILIES_PATH}/icon_question.gif" alt=":" title="Question" /><!-- s:?: -->

From what i have been told before when they jump out the water they are cleaning off parasites that they get from when the feed in the silt. Dont know how true this is though.
Think that sometimes when they jump out the water and land on their sides like whales its more for fun than anything.
Next few posts will no doubt prove me very wrong. <!-- s:lol: --><img src="{SMILIES_PATH}/icon_lol.gif" alt="" title="Laughing" /><!-- s:lol: -->

They dont seem to do it on some lakes which is even stranger. Any ideas why?

Not sure of the exact reason but all i know is that when this happens a lot is usually a sign of them feeding quite confidently. From my experience i have usually caught well when this happens but as with everything in fishing of course this is not always the case.

One thing i do know is if i see a carp topping, especially in the winter then chuck a bait on its head. Often the only sign of where the carp are when its cold.