video: This is a black cat grooming its fur, displaying the papillae on the tongue. view more
Credit: Alexis Noel
A study explores how cats groom fur using fine structures called papillae on the surface of the tongue. Domestic cats, which sleep on average 14 hours each day, spend up to a quarter of their waking hours grooming, which removes fleas, debris, and excess heat from fur. Cats' tongues are carpeted with hundreds of sharp, scoop-shaped spines called filiform papillae, which are composed of keratin and spring into action during grooming. Alexis Noel and David Hu used high-speed videos, CT scans, and grooming force measurements to explore how papillae aid grooming in postmortem tongue tissues from six cat species--domestic cat, bobcat, cougar, snow leopard, tiger, and lion. Experiments revealed that U-shaped hollows at the tips of papillae wick saliva from the mouth, each wicking action capturing up to 4.1 μL of saliva, tantamount to one-tenth of the drop of a typical eyedropper. Each lick of the tongue deposits nearly 50% of the fluid on the tongue onto fur and can deliver a substantive fraction of the cooling effect required for regulating body temperature. Further, the ease of grooming depends on whether papillae can penetrate fur to reach the skin, explaining why some species of domestic cats, such as long-haired Persian cats, are covered in fur that mats easily and is notoriously difficult to groom. Using the insights, the authors fashioned a cat-tongue-inspired hairbrush that is easier to clean than human hairbrushes. According to the authors, the biologically inspired hairbrush might prove a handy implement to remove allergens from cat fur and apply cleaning lotions and medications on cat skin.
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Article #18-09544: "Cats use hollow papillae to wick saliva into fur," by Alexis C. Noel and David L. Hu.
MEDIA CONTACT: David Hu, Georgia Institute of Technology, Atlanta, GA; tel: 404-894-0573; e-mail: hu@me.gatech.edu
Journal
Proceedings of the National Academy of Sciences