Worlds largest dog..... The worlds heaviest as well as longest dog ever recorded was an Old English Mastiff named Zorba. In 1989, Zorba weighed 343 lbs and was 8 feet 3 inches long from nose to tail!
Worlds tallest dog..... The tallest dog on record was named Shamgret Danzas. He was 42 inches tall (at the shoulder!) and weighed 238 lbs.
Worlds smallest dog..... The smallest dog in history was a tiny Yorkie from Blackburn, England. At two years of age and fully grown this little dude was an incredible 2.5 inches tall by 3.75 inches long! He weighed only 4 ounces! HE was approximately the size of a matchbox.
Worlds oldest dog..... The oldest dog that has been reliably documented was an Australian cattle-dog named Bluey. He was put to sleep at the age of 29 years and 5 months!
Worlds Best Drug Sniffing Dogs.....A US Customs Labrador named "Snag" has made 118 drug seizures worth a canine record $810 million. The greatest number of drug seizures by dogs is 969 in 1988. IN ONE YEAR! The team of "Rocky" and "Barco" patrolled the Texas and Mexico border, alias "Cocaine Alley." They were so good that Mexican drug lords put a price of $30,000 dollars on their heads.
(All this cool info is from the site http://www.dogquotes.com/dogfacts1.htm)
