Tag: coat

Science

How do cats use their whiskers?

mehshadoweye

Meredith Hemphill

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Close-up of tabby cat's whiskers
Photo by David Mark from Pixabay

Whiskers, known in the scientific world as vibrissae, are sense organs common among mammals. Because humans completely lack these specialized hairs, it is difficult, if not impossible, for us to really understand what animals that have them experience. It is a completely different, sixth sense that enables them to learn about their environment in a way that we cannot. Research has given us mere humans insight into how whiskers function, though, and how to be considerate of our furry friends’ precious whiskers.

Whiskers on Kittens

A whisker is a long, thick hair, which grows from a hair follicle like a cat’s fur does (2, 4). However, the hair follicles that make whiskers are different from the ones that make fur in a few important ways. For one, whiskers are rooted three times deeper into the skin than regular hairs (2, 6). The follicles for whiskers also have far more blood vessels and nerves (2, 4, 6). This heightens the sensitivity of the individual whisker hairs.

Cats have whiskers on their muzzles, chins, and forelegs; above their eyes; and near their ears (2-6). The number and length of whiskers varies. Most cats have 12 whiskers on either side of their noses (2, 6). Whiskers are usually light in color, but some cats may have black or brown whiskers, or a mix of colors. The color of a cat’s whiskers may even change over their lifetime (6, 7).

How Do Whiskers Work?

Although whiskers are sometimes called tactile hairs, the whiskers themselves don’t have any sense of touch. Rather, the movement of the whiskers triggers the nerves in the hair follicle, and that information is sent to the brain (2, 4, 5). This can tell a cat about the location, size, movement, and texture of an object as well as more general environmental information (2-5).

On the end of each whisker is a tiny organ called a proprioceptor (2, 4). Proprioceptors detect vibrations in the environment (4). They enable a cat to sense the position of its own body and all the components thereof in space (2, 4).

What Are Whiskers For?

Animals use whiskers for a lot of different things. Scientists have discovered that, depending upon the species, whiskers are involved in “food acquisition, prey attack, aggression and attack behavior, facial expression in intraspecies communications, dispersion of pheromones, maintaining head position in swimming, and a wide range of environmental monitoring (e.g. current detection in water, wind direction on land)” according to A. S. Ahl (1). Even in cats alone, whiskers serve a variety of functions.

Close-up of white cat's whiskers
Most cats have 12 whiskers on each side of their nose – Image by birgl from Pixabay

Cats are somewhat farsighted. Whiskers compensate for the trouble cats have focusing on objects close-up (2, 6, 7). This can be particularly important for hunting. Once a cat pounces on their prey and has it in their paws, their whiskers help them “see” to tussle with it and deliver the fatal bite (2, 4, 6). Many of the animals cats prey on also have whiskers, though, which can help them to sense cats coming (5).

A cat’s whiskers tell them if they can fit into a space or not (2, 4, 6, 7). Their muzzle whiskers are as long as they are wide (4, 6), so whether the whiskers bend when a cat puts its head in a space tells it if the rest of its body will fit. Whiskers don’t just protect cats from getting stuck in tight places, though. They also protect delicate parts of their bodies from damage (2). The whiskers on the face, especially those above the eyes, alert cats to objects that pose an imminent risk to their eyes (2). Whiskers can detect trouble as small as a speck of dust.

Whiskers serve a social function, as well. Cats communicate with each other mostly through body language. We can learn to understand these messages, too. The position of a cat’s whiskers provides one clue to their emotions. If your cat is relaxed, her whiskers will be as well, sticking straight out to the sides (4, 6). If they are excited, curious, or alert, they’ll push their whiskers forward (2, 4, 6). A cat that is angry or scared will pin their whiskers back against their face (4, 6).

Whisker Do’s and Don’ts

DO be mindful of whisker fatigue. Whisker fatigue is the pain and stress cats experience when their food and/or water bowls regularly brush up against their sensitive whiskers (3, 4). Tall, narrow bowls tend to be the culprit (3, 4). Be kind to your cat’s whiskers, and use wide, shallow bowls instead (3, 4, 6). Symptoms of whisker fatigue include:

  • Scooping food out of the bowl and eating on the ground
  • Making a mess while eating/drinking
  • Leaving food in the bowl but acting hungry
  • Approaching the food/water bowl with caution; pacing nervously before eating/drinking
  • Refusing to eat unless the bowl is full
  • Mealtime aggression (3)

DON’T cut your cat’s whiskers, ever. Number one, it’s painful for them (7). Number two, it disorients and confuses them (2, 4, 6, 7). For blind cats or cats that spend time outside, that is extra dangerous. There is no health reason to trim a cat’s whiskers, and it is not worth it just for aesthetic reasons.

Tabby kitten between wall and planter
Image by keziaschen from Pixabay

DO check with your vet if you feel like your cat is losing a lot of whiskers. Whiskers fall out and are replaced when they get old just like any other hair. However, losing many whiskers in a short period of time can be an indication that something is wrong. Numerous skin conditions such as acne, allergies, and infections can cause whisker loss (7). So if your cat is losing whiskers frequently or en masse, consult your veterinarian (7).

DON’T play with a cat’s whiskers. Whiskers are cute, and it’s tempting to touch them, but most cats will find anything more than a gentle stroking uncomfortable. If you find a shed whisker, however, go nuts. I have a friend that uses her cats’ shed whiskers as tiny paintbrushes.

Fun Facts

  • Some cats may have curly whiskers, especially if they are of a curly-coated breed.
  • The word “whisker” dates back to about 1600. It comes from the Middle English “wisker,” meaning anything that whisks or sweeps. (4)
  • Each individual whisker can be traced to a specific spot in a cat’s brain. (2)

Works Cited

  1. Ahl, A. S. (1986). The role of vibrissae in behavior: A status review. Veterinary Research Communications, 10, 245-268. https://doi.org/10.1007/BF02213989
  2. Buzhardt, L. (n.d.). Why do cats have whiskers? VCA Hospitals. https://vcahospitals.com/know-your-pet/why-do-cats-have-whiskers
  3. Does your cat have whisker fatigue? (n.d.). CatHealth.com. https://www.cathealth.com/cat-care/nutrition/2389-does-your-cat-have-whisker-fatigue
  4. Hagerman, J. (2020, December 15). Everything you ever wanted to know about cats’ whiskers. Pasadena Humane. https://pasadenahumane.org/everything-you-ever-wanted-to-know-about-cats-whiskers/
  5. How do whiskers work? (n.d.). Discover Wildlife. https://www.discoverwildlife.com/animal-facts/mammals/how-do-whiskers-work/
  6. Kelley, J. A. (2020, January 29). 7 cool facts about cat whiskers. Catster. https://www.catster.com/cats-101/cat-whiskers-facts
  7. Why is my cat losing his whiskers? (n.d.). Canidae. https://www.canidae.com/blog/2019/04/why-is-my-cat-losing-his-whiskers/

Published June 13th, 2021

Updated May 12th, 2023

Science

Coat Pattern Genetics

mehshadoweye

Meredith Hemphill

mehshadoweye

Encyclopaedia Felidae now has a Patreon! Go to www.patreon.com/EncyclopaediaFelidae if you want to help support this content!

A few weeks ago I wrote about the genetics of coat color in domestic cats. Now, to follow up, I am going to dive into the wild world of pattern genetics. If you would like a review of basic genetic principles, click the link to the previous article. There is a quick rundown in the beginning.

In genetics, the “wild type” is the genetic profile of an organism that is most common under natural conditions. The wild type ancestral cat was a mackerel tabby with black stripes, short fur, and no white spots [1]. Today, of course, cats come in a wide variety of patterns, even those who live feral and are subject to natural selection. Both human intervention and spontaneous mutations are to credit for this diversity.

Tabby

Let’s start with tabbies, the original cat pattern. Many other cat species share the tabby pattern with domestic cats, usually in the form of rows of spots–spots and stripes are closely related genetically in cats [2, 3]. In order to have a tabby pattern, a cat must first have at least one dominant allele at the agouti locus. The dominant agouti allele causes each individual hair to have bands of darker and lighter pigmentation. This is required for tabby coats and several other patterns which we will come to later.

The wild type mackerel tabby pattern is characterized by thin, parallel stripes darker than the background color. Mackerel tabby is the dominant allele at the Tabby, or Ta, locus, so only one TaM allele is required for the mackerel tabby pattern. The “blotched” or “classic” tabby has large, marbled stripes. This pattern occurs at the same Ta locus. The blotched allele is recessive to the mackerel.

Spotted tabby kitten with toys
Spotted tabby kitten – Photo by Kim Davies on Unsplash

At least two other alleles are involved in tabby patterning, although it was previously thought that there was only one [4]. The Ticked locus has been definitively identified as influencing the type of tabby pattern a cat’s coat has, but another unknown locus or loci may effect how the patterns present [4].

The Ticked locus is epistatic to the Tabby locus, meaning that the genotype at the Ticked locus has an impact on the phenotype coded for by the Tabby locus. If a TiA allele is present at the Ticked locus, the cat will have ticked/agouti fur all over the body, as the TiA allele masks the effect of the Tabby locus. This is usually called an Abyssinian Tabby because the ticked coat is characteristic of the Abyssinian breed. If there are two Ti+ alleles, the cat will not be an Abyssinian tabby, and whatever genotype is at the Tabby locus will show through. Cats with one TiA and one Ti+ allele tend to have some striping on their faces, legs, and tails despite being Abyssinian tabbies.

Tired of talking about tabbies? I hope not, because we still have to go over the special cases! Spotted tabbies have stripes that are broken into spots of varying size. An unknown modifier gene or genes are believed to alter the expression of mackerel tabby stripes to create spotted tabbies [4]. The charcoal Bengal/Savannah patterns are a variety of tabby caused by an agouti gene inherited from the Asian Leopard Cat. Charcoal tabbies have decreased red tones in their coats, giving them a cooler, grayer appearance. They also have a dark nose and “Zorro” mask on the face and a dark cape down the back. There are a shocking number of other types of modified tabby, but the genetics behind them are hazy. I will leave you with a handy infographic showing you what they look like and move on to the next pattern.

Table of tabby patterns
Chart of Tabby Patterns – Image from messybeast.com

Silver and Gold

Agouti hairs would normally have alternating bands of light and dark pigment corresponding to the cat’s coloring, but there are a couple genes, or possibly gene families, which can change the way pigment is deposited on agouti fur. A dominant mutation of the Silver/Inhibitor gene inhibits production of phaeomelanin, the yellow or red pigment in cat hair. This causes the light portions of agouti bands to be very pale or colorless rather than yellow. This mutation, by itself, causes tabbies to be silvery and solid-colored cats to have a pattern known as smoke, where there is a pale/colorless band at the bottom of their hair shafts. Their white undercoats give them a “smoky” appearance when their fur is ruffled.

On the other hand is the Wide-Banding trait, only present in agouti cats. It is thought to be caused by a group of related genes, but this is still unclear, and no one quite knows how they work. Whatever the root cause, wide-banding causes the agouti bands on the hair shaft to be larger and/or more numerous. There is a high degree of variation in the way this can present, lending credence to the idea that there is more than one gene involved.

Silver Persian and kitten in cat tree
Silver shaded Persian (top) – Image by RomeoEbaloo from Pixabay

When Wide-Banding occurs alone, the cats are sometimes referred to as “golden” due to the higher degree of yellow pigment in their coats. However, the Silver and Wide-Banding traits can occur together to create other patterns. In either case, cats with Wide-Banding that leaves only the very tip of the hair shaft to show their normal pigmentation are said to be tipped. Those with more of the darker pigment on the end of the shaft are called shaded. There are even more names among cat fanciers for the many different combinations of these phenotypes, but we have more to cover.

Color-point

We touched on color-pointing in the Siamese breed profile, and we will probably circle back to it with other breeds. It is a popular pattern which has been deliberately bred into quite a few breeds. Color-pointing is a kind of partial albinism. These cats have a mutation in tyrosinase, an enzyme required for the production of melanin. The mutated enzyme will only activate below 33 degrees Celsius. As such, the mutation causes temperature-sensitive pigmentation, with the most color deposited on the coolest extremities of the body. There are actually two color-point alleles that result in three somewhat different phenotypes. Both alleles are recessive to the wild type allele but are codominant to each other.

Brown and cream cat with blue eyes
Tabby Himalayan color-point – Photo by Nathz Guardia on Unsplash

The Himalayan phenotype has the strongest color restriction. It is seen in cats with two cs alleles. These cats have blue eyes and a very light-colored torso, typically cream or ivory. The color-pointing is very high-contrast. The intermediate phenotype is known as Mink and is typical of the Tonkinese breed. They have one cs allele and one cb allele. The eyes are aqua and the torso color is more similar to the points.

The Sepia color-points are not all sepia but are named for the brown Burmese cats wherein the pattern was first identified. This phenotype has copper eyes and is quite low-contrast, with the points and the torso being fairly similar in color. Sepia color-points have two cb alleles. All color-point cats can have points of any color, and the points can also be patterned. Sometimes color-point and white spot patterns can be combined to form new patterns, such as white mittens (characteristic of Birmans) or bicolor. For more on white spots, see the coat color article.

There are a LOT of miscellaneous mutations that I could talk about which are not so widespread or well-documented as the ones I have covered here today. If you would like me to go over them in the future, please let me know. I would be glad to do so. You can also tell me if you never want me to do this again. Feedback is always welcome. :3

Works Cited

  1. Hampton, N. (1998, March 4). Coat color and pattern genetics of the domestic cat (Felis catus) [PowerPoint slides]. The University of Texas at Austin. https://facultystaff.richmond.edu/~lrunyenj/bio554/cat/index.htm.
  2. Thomas, E.M. (1994). The tribe of tiger: Cats and their culture. Simon and Schuster.
  3. Zielinksi, S. (2012, September 20). Same gene guides cheetah and tabby cat coat patterns. Smithsonian Magazine. Link here.
  4. Eizirik, E., et al. (2010). Defining and mapping mammalian coat pattern genes: Multiple genomic regions implicated in domestic cat stripes and spots. Genetics, 184(1), 267-75. DOI: 10.1534/genetics.109.109629

Published April 10th, 2020

Updated June 14th, 2023

Science

Coat Color Genetics

mehshadoweye

Meredith Hemphill

mehshadoweye

Encyclopaedia Felidae now has a Patreon! Go to www.patreon.com/EncyclopaediaFelidae if you want to help support this content!

Five tabby kittens
Colorful kittens – Photo from Pixabay

I majored in genetics as an undergraduate, so whenever I see a cat with unusual patterning or coloration, I can’t help but wonder what molecular wizardry made that possible. Cat fanciers have long wanted to unlock the mysteries of feline traits. While breeders began to puzzle out the patterns before DNA was determined to be the blueprint of heredity, there are still some mysteries to be solved. However, the more obvious traits have been mapped onto the feline genome, and there are even DNA tests for breeders or uncommonly curious pet owners who want to know what genes their cats carry. Today I want to cover the basics of coat color genetics, but I’ll start with a quick overview of genetics so no one gets lost. Feel free to skip it if you know you don’t need it.

Genetics: A Primer

DNA (deoxyribonucleic acid) is the molecule on which all the necessary information to build an organism is stored. Each unit of storage in the DNA is called a gene, and genes code for proteins. Proteins serve an incredibly wide variety of biological functions in the organism, including providing structure and metabolizing food into energy. There can be multiple different versions of a gene in the gene pool of a species. These different versions are called alleles.

Because an individual inherits half of their DNA from each of their parents, they have two copies of each gene. There are species for which this isn’t true, but it is for most vertebrates, including cats and humans. So each individual should have two copies of every gene, with a notable exception that we will get to later, but some alleles are dominant to others, so not every allele will be expressed. In the case of simple dominance, dominant alleles will be expressed if they are present. However, if the individual has inherited a recessive allele from both parents, they will express the recessive trait.

If you’re confused, I recommend looking up a more thorough overview of basic genetics before proceeding. There is much more to be said on the point, and I will do my best to explain as I go along, but it is only going to be more complicated from here. Now, let’s talk about what makes cats so very colorful!

Tom and the Monochromatic Fur Coat

Cats have two coat color pigments: eumelanin, which is black or brown, and pheomelanin, which is red or yellow. The primary coat color gene produces eumelanin. There are three alleles. The dominant allele, B, leads to black fur. The b allele is recessive to B and produces less pigment, leading to a brown coat, sometimes called “chocolate.” The b1 allele is recessive to both B and b, and it leads to a light brown or “cinnamon” coat.

The pheomelanin gene has a dominant allele, XO, that produces a red/orange coat color instead of or in addition to the color at the black/brown locus. The recessive allele, Xo, produces no reddish pigment. The pheomelanin gene is different in that it is located on the X-chromosome. In mammals, females have two X-chromosomes and males have one X and one Y, with some exceptions because biology is complicated.

So tom cats only have one gene for orange pigment, which they inherit from their mother. That is why toms are either ginger or black, but only very rarely both. But she-cats can have a XO and a Xo allele, causing them to have patches of both orange and black. This pattern is called tortoiseshell, or calico if they also have white patches. Tortoiseshell and calico toms can be born if they have two X-chromosomes and a Y or a similar chromosomal anomaly.

White cat with plush cow
White cat with odd eyes. Also a cow. – Photo by Samson Andreea on Pexels

50 Shades of White

White patches are due to the piebald spotting gene, where the recessive, s, allele codes for no white. If a cat has just one dominant allele, S, less than half of their fur will be white, and the white patches are often restricted to the feet, face, chest, and underside. If they have two dominant alleles, more than half of the cat will be white. It’s possible that they may even be completely white.

There are two other ways that a cat may be white, genetically speaking. The dominant white gene, as the name suggests, produces solid white cats with at least one dominant W allele. These cats are likely to be deaf, especially those with blue eyes and odd eyes. Those with odd eyes tend to be deaf in the ear on the same side as the blue eye. Rarely, white cats may be albino. There are two alleles that cause albinism, both recessive and both defective versions of the allele coding for the tyrosine enzyme. Cats with two c alleles are true albinos and have a translucent white pelt with pink eyes. Two ca alleles produce a white coat with pale blue eyes. There is no association of deafness with albino cats.

A Dilute Shade of Pale

The dilution gene is capable of modifying the appearance of other colors. The dominant allele produces the normal coloration. Two recessive alleles causes the pigment granules to clump in the hair shaft and leave large areas without pigment. The result is a lighter, or diluted, coloring. Black cats become grey, known as “blue” in the breeding world. Chocolate becomes lilac, cinnamon becomes fawn, and ginger, or “red,” becomes cream.

This covers the basics, although certain breeds can have unique alleles, such as the amber allele at the orange locus in Norwegian Forest Cats. I will cover the genetics of coat patterns another week. Until then, enjoy this picture of my gorgeous blue-cream calico.

Published February 20, 2020

Updated June 20, 2022