More Episode 14: Why, and How, Cats Purr and Cold Wet Noses

Why (and How) Cats Purr

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A cat’s purr is a unique thing in so many ways. A purr is unlike most other vocalizations because it can occur both with an inhalation (breathing in) and exhalation (breathing out), unlike most meows, barks and speaking, which occurs only on exhalation. Special wiring in their brain allows them to dilate their glottis (which is part of the larynx). The larynx and pharynx are the part of the neck where the nasal cavity and the mouth combine and the windpipe and esophagus (food pipe) exit, and where the vocal cords reside.

Being able to make noise while breathing both in and out is very uncommon. Not even all “cats” can make this noise. While Bobcats, Cheetahs, Lynx,  and Pumas can purr,  cat in the Patherinae subfamily, such as  Lions, Leopards, Jaguars and Tigers cannot. Lions actually have bone growth in part of their larynx which allows them to roar instead.

Other animals make purring sounds, such as mongoose, bears, badgers, rabbits, squirrels, guinea pigs, tapirs, elephants and even gorillas, but these are exhalation only noises and not true “purrs”

Cat KneadingHouse cats purr when content, but also sometimes when nervous or uncomfortable. Mother kittens purr to with their kittens commonly, which may help with bonding. Many pet owners report that their pets purr while performing kitten like behaviors such as kneading or suckling.

Some scientists theorize that cats purr so frequently because we inadvertently train them. Pet owners enjoy the purring, and give them attention and love, further encouraging more purring. Feral (homeless, wild cats) purr as well though, so some purring must be natural to cats.

Cat purr at between 25 mhz and 150 mhz, which is a frequency scientists have shown increases bone density, stimulates muscle growth and promotes healing. Some now theorize that a cat purring allows it to maintain their muscle mass despite getting minimal exercise (with their rigorous 16 to 20 hours a day sleeping schedule.) A happy cat may be purring from contentment, but cats purring while uncomfortable may be actually trying to heal themselves.

Cold Wet Noses: Who Cares, and What Works Better

A cold wet nose is renown as the indicator of pet health, but does it really mean anything? If a dog or cat is feverish or dehydrated, the nose may be dry and warm, but other problems won;t affect nose moisture or temperature at all. If you really want to check your pet’s temperature, take their temperature with a regular human rectal thermometer. Please do not do this if your pet is the type that will injure you or themselves if you attempt this.

Normal dog and cat temperatures range from 99 to 102.5 fahrenheit (37.5 to 39.2 celsius). Newborns temperatures may be lower (down to 97) and excited pets may go a little higher.



If you are worried about your pet being seriously sick, mucous membrane color and capillary refill time are a much better indicator than a cold wet nose. You pets mucous membranes, or the gum tissue under the lips and around the teeth, should be pink and moist. Pale or white mucous membranes could indicate anemia, and dry mucous membranes occur with dehydration.

Capillary refill time is a way to check blood pressure. This is done by lightly pressing on the gums until they go pale, releasing, and then counting how long it takes the gums to return to pink. The capillary refill time (or CRT) should be less than 2 seconds. More than 2 seconds, and something is significantly wrong.



For more information, Listen to the Podcast

From the podcast:

John apparently really likes Jessica Rabbit from Who Killed Roger Rabbit.

John and Boogie


Links to how cats can reduce high blood pressure, or your chance of a heart attack, and dogs reduce the risk of asthma.

Links for the Florida Stand Your Ground Law.

Links for more information about the tiger’s giant hairball.

Links about Gorilla Glue.

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