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.
The call of the mighty blue whale is the loudest on Earth, registering a whopping 188 decibels. (The average rock concert only reaches about 100 decibels.) Male blue whales use their deafening, rumbling call to attract mates hundreds of miles away.
Found in the rain forests of the Americas, this monkey grows to about four feet tall and has a howl that can travel more than two miles.
When an elephant stomps its feet, the vibrations created can travel 20 miles through the ground. They receive messages through their feet, too. Research on African and Indian elephants has identified a message for warning, another for greeting, and another for announcing, "Let's go." These sounds register from 80 to 90 decibels, which is louder than most humans can yell.
North American Bullfrog
The name comes from the loud, deep bellow that male frogs emit. This call can be heard up to a half mile away, making them seem bigger and more ferocious than they really are. To create this resonating sound used for his mating call, the male frog pumps air back and forth between his lungs and mouth and across his vocal cords.
If you happen to hear the call of a "laughing" or spotted hyena, we recommend you leave the building. Hyenas make the staccato, high-pitched series of hee-hee-hee sounds (called "giggles" by zoologists) when they're being threatened, chased, or attacked. This disturbing "laugh" can be heard up to eight miles away.
Perhaps the most recognizable animal call, the roar of a lion is used by males to chase off rivals and exhibit dominance. Female lions roar to protect their cubs and attract the attention of males. Lions have reportedly been heard roaring a whopping five miles away.
Northern Elephant Seal Bull
Along the coastline of California live strange-looking elephant seals, with huge snouts and big, floppy bodies. When it's time to mate, the males, or "bulls," let out a call similar to an elephant's trumpet. This call, which can be heard for several miles, lets other males -- and all the females nearby -- know who's in control of the area.