^ Uhm, that was actually proven to be false. Apparently some or other scientist actually took the time to test this and found out that a duck's voice (quack) does indeed resonate, albeit more softly than other sounds.
I know, I've read it somewhere and it proven to be false, just posting..
more:
o. Shark tooth loss is more than 6000 pieces every year, and new teeth grow within 24 hours
o. Julius Caesar was killed with 23 stab wounds
o. Giraffes and rats can last longer without water than camels
o. Your stomach produces a new layer of mucus every two weeks so that it does not digest itself.
o. 98% of rapes and murders committed by a family member or close friend of the victim.
o. Ants can lift 50 times its body
o. American Declaration of Independence was written on paper of marijuana
o. The dot over the letter i is called a "title"