Dogs

   Why can dogs hear so much better than humans? Dogs can hear higher frequencies than humans can. Puppies are born deaf and when some dogs age they may become deaf.  At the low end of the range dogs can hear about 40 hertz, while humans can hear about 20 Hz. At the high end dogs can hear about 45 Hz and Humans, 23 Hz. Dogs can hear higher pitches than humans do. They may bark at a vacuum cleaner because of the high annoying pitch. Dogs ears are more mobile. Dogs with ears standing up have better hearing then dogs with hanging ears. 

Citation:

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 "Understanding a Dog's Senses." Understanding a Dog's Senses. N.p., n.d. Web. 27 Jan. 2014.

 "Nice Dogs." Flickr. Yahoo!, 25 May 2008. Web. 29 Jan. 2014.