Four Animal Facts: Hearing Edition (Part 2)

Tarantulas “Feel” Sounds

“If a tree falls in a forest and there’s no one around to hear it, does it make a sound?”

For tarantulas, this age-old philosophical question has an answer: Yes. While they do not possess ears or an auditory cortex, and therefore lack the ability to hear like we do, tarantulas use sound waves to navigate the world. They have extremely sensitive hairs on their legs that feel the displacement of air when a sound is emitted. Some smaller spiders, like jumping spiders and ogre-faced spiders, actually have special nerve cells on their forelegs that send signals to the brain when certain frequencies are detected. Studies have shown that the accuracy of this “hearing” is remarkably accurate. Sound waves can help the spiders pinpoint the location of prey up to six feet away.

 

Whales Can Communicate Long-Distance

For decades, the hearing capabilities of dolphins and whales mystified scientists. These animals could obviously hear very well underwater, but since they lack external ears, marine biologists wondered how. Now we know that whale skulls amplify sound through bone conduction. Even more amazing is the fact that baleen whales, such as humpbacks and blues, are capable of vocalizing over a distance of tens of thousands of miles. This means that a whale swimming in Ireland can have a conversation with another whale basking in the Caribbean!

Unfortunately, there is a growing body of research that suggests that human activities like oil drilling and commercial fishing have made our oceans so noisy that whales are having trouble hearing one another. Scientists aren’t yet sure what the consequences of these findings will be, but since sunlight does not penetrate water very well and whales must rely more on hearing than eyesight, it’s likely that their migration and mating patterns will be disrupted.

 

Pigeons and Moths Have the Best Hearing in the Animal Kingdom

There’s a reason pigeons have long been renowned for their incredible navigational abilities: They have extraordinary hearing! Much of this ability is due to their detection of infrasound, which occurs in frequencies too low for the human ear to hear. Some of this infrasound even comes from the earth’s electromagnetic field, giving pigeons a 360-degree sonic view of their surroundings and allowing them to easily map the landscape.

And what about the best high-frequency hearing? That honor goes to certain moth species, which often detect sounds up to 300,000 Hz. For comparison, the upper range of human hearing extends only to about 20,000 Hz. These moths are locked in an evolutionary race with the bats that prey on them, with each species developing more acute hearing over the passing of time.

 

Pet Birds Enjoy Music

It’s commonly accepted wisdom that playing music for your parakeet, cockatoo, or finch will make your bird happy, but is it true? Turns out, it is! Bird brains process musical sounds in much the same way human brains do, and — just like us — birds are individuals, with their own likes and dislikes. Some parrot owners have discovered, much to their chagrin, that their feathered friends’ favorite tunes are in a genre they can’t stand. This can be especially frustrating with male birds, who often incorporate songs that they enjoy into their repertoire. Fortunately, most birds appreciate soft, relaxing music, such as classical and smooth jazz, regardless of their personal taste. If you share your home with one of these wonderful animals, try creating a playlist for the two of you to enjoy together.

 

If you loved this article, be sure to check out these four other amazing animal facts!

 

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Sources:

Yong E. The Insect That Hears Like a Human, With Ears on Its Knees.

https://www.nationalgeographic.com/science/phenomena/2012/11/15/the-insect-that-hears-like-a-human-with-ears-on-its-knees/. Accessed Nov. 22, 2019. DOSITS. Hearing in Cetaceans and Sirenians, the Fully Aquatic Ear. https://dosits.org/animals/sound-reception/marine-mammals-hear/hearing-in-cetaceans.  Accessed Nov. 22, 2019. St. Fleur N. An Elephant’s Silent Call. https://www.sciencemag.org/news/2012/08/elephants-silent-call. Accessed Nov. 22, 2019. Snowden C, et al. Cats Prefer Species-Appropriate Music. Applied Animal Behaviour Science. 2015;166:106–111.