40 day-old fetuses: Optical vesicles had pigmented retina and no eyelashes, prominent ears, formed nostrils, with the presence of small tactile hairs in the nasal region, open mouth with lip filter and lateral lip commissures.
50 day-old fetuses: The fetuses showed complete differentiation of the body regions, with defined facial characteristics, such as closed eyes and small eyelashes, formed ears, nostrils presenting developed tactile hairs and with dark colored pigmentation.
All these whiskers, or "vibrissae," are stiff tactile hairs
that help your cat learn about her environment.
Animal hairs are classified into three basic types: a) "primary" or "guard" hairs that form the outer coat of an animal and provide protection from sunlight, moisture; b) "secondary" hairs (also known as fur or wool hairs, or the undercoat) that form the inner coat of an animal and provide insulation; and c) tactile hairs
(whiskers) that provide sensory functions.
* Tactile hairs (whiskers) that are found on the head of animals and provide sensory functions
Tactile hair: (Vibrissae): Whiskers only found on animals.
* Minimum velocity constraint: Spiders are sensitive to the slightest air movements through their tactile hairs
They use these tactile hairs
to sense and navigate their environment.
(Vibrissae): Whiskers only found on animals.