Animals send out messages for very specific reasons, such as to signal danger or for mating rituals. Some of these calls, like the ones that follow, are so loud they can travel through water or bounce off trees for miles to get to their recipient.
Please copy/paste the following text to properly cite this HowStuffWorks article:
the Editors of Publications International, Ltd.. "7 Animals that Can Be Heard for Long Distances" 30 October 2007. HowStuffWorks.com. <http://animals.howstuffworks.com/animal-facts/7-animals-that-can-be-heard-for-long-distances.htm> 29 August 2014.