According to the announcement from Guinness World Records, Smokey's purr peaked at 67.7 decibels, which is about the sound of a rather loud human conversation. By comparison, the average cat purrs at about 20 decibels, meaning that Smokey's utterances are about 16 times louder than what you would expect from a domestic cat.
According to Smokey's website, smokeythepurringcat.com, securing the record wasn't easy for Ruth Adams, Smokey's owner. In the first attempt, which was made on March 25 and witnessed by a sound technician from Northampton College, a veterinary nurse, a representative from the UK's Cat's Protection charity, and a Member of Parliament, the cat peaked at 73 decibels at a distance of one meter. But the sound technician used a decibel reader that wasn't equipped to provide the data printouts required by Guinness. So they had to try it again.
During the second attempt – which the Member of Parliament was unable to attend – Smokey, enticed by a piece of ham, purred at 67.7 dB, setting the official world record.
Even though it is heard on millions of laps, warm laundry piles, and floor heating vents every day, scientists are unsure exactly what produces a cat's purr, although most agree that the sound emanates from the cat's larynx and associated muscles and is signaled by a neural oscillator in the cat's brain.
Members of the Felinae subfamily, which includes house cats, cheetahs, bobcats, lynxes and pumas can purr while exhaling and inhaling. Members of the Pantherinae subfamily have been observed make a purr-like sound only when exhaling.
The Guinness announcement also noted that the loudest sound by any living source comes from the blue whale, whose low-frequency pulses can hit an astounding 188 decibels. But we think Guinness might have overlooked the Alpheidae, a family of tiny shrimp whose snapping claws can produce a sound of up to 218 decibels. The shrimp uses its claw as a sonic weapon, creating a pressure wave that it uses to kill small fish, earning it the nickname "pistol shrimp."