Calico and tortie (tortoiseshell) are both common coat colours/patterns which appear almost exclusively in female cats. The terms calico and tortie are often used interchangeably, and it is easy to see why. Both patterns refer to a multi-coloured cat which may consist of black and orange, brown and orange, grey and cream with or without white.
Cleaning litter trays is one of the less enjoyable aspects of sharing a home with a cat, but a necessary one. Dirty litter trays not only smell unpleasant to us but our cats as well. Proper litter tray husbandry is vital, dirty litter trays can lead to inappropriate elimination.
A black or green tattoo on the inner portion of a cat’s ear is to show that the cat has been desexed (spayed or neutered). The veterinarian adds the tattoo during spay/neuter surgery.
Do all veterinarians and rescue centres tattoo cat ears?
Not all cats who have been desexed will have a tattoo, only one out of my four has an ear tattoo.
Trap, neuter & return (TNR) feral cats may have a notch out of their ear instead of a tattoo. Due to their fear of humans, the ear notch makes it easy to determine if the cat has been desexed from a distance.
You can see in the photo the tip of the cat’s ear has been removed, some veterinarians will remove a portion of the ear from the side instead of the tip. This procedure is carried out during the spay/neuter operation. While tattoos work for tame cats, they can be hard to see from a distance on feral cats. Which makes the notch a more reliable option.
Can pet owners tattoo cats?
Laws can vary from country to country and region to region, but most places would consider tattooing or piercing animal abuse. While adults can make an informed choice, cat’s can’t and pet owners run the risk prosecution for tattooing a cat. The ear tattoo serves a useful purpose and is performed on the cat under anesthesia, cosmetic tattoos serve no useful purpose.
How to determine if a cat has been spayed or neutered
Not all cats have an ear tattoo or notch to easily identify a desexed cat. When a male cat is neutered (orchidectomy), an incision is made in the scrotal sac and the testicles are removed, leaving the sac intact. This makes it easy to identify a neutered male. The only exception is if the male is cryptorchid, which means one or both of the testicles hasn’t descended into the scrotum, which can give the appearance of a neuter.
Other identifying clues include the presence of barbs on the penis of males who were neutered before six months and stud jowls on entire adult males.
It can be more difficult to determine if a female cat has been spayed which necessitates shaving the fur to look for a spay scar. Females may be spayed midline or flank, so if a scar cannot be found midline, then a second patch of fur will be shaved. The absence of estrus (heat) is another good clue that the female has been desexed. Entire cats will have repeat heat cycles until or unless she mates. During estrus, the female will roll on the ground, or if touched along the back close to the tail, will assume a mating position with the front part of her body low, and the rear half raised.
As I work in human eyecare and we are fast approaching the year 2020, there is an increasing focus (pardon the pun) on 20/20 vision along with bad jokes. But what exactly is 20/20 vision and do cats experience a decline in vision the way humans do?
Visual acuity refers to the clarity of vision, and 20/20 vision means that the test subject can see the same line of letters at 20 feet as a person with normal vision can see at 20 feet. People of all ages (including young children) can have refractive errors, which occur when the eye cannot focus properly, and they will find it hard to see close up (farsighted or hyperopia) or distance (near-sighted or myopia).
One of the most common types of refractive errors occurs as people move into their late 30s and early 40s. Many will notice a decline, usually with their close up vision. They find it hard to read text on their phones, or menus; this type of refractive error means they are farsighted (presbyopia) due to age. The decline in the ability to focus due to age develops because the lens, which sits behind the pupil loses its ability to change shape and properly focus light on the retina located at the back of the eye. Optometrists can correct refractive errors with glasses or contact lenses.
If you have ever seen an optometrist write a script, he or she will use numbers which tells the optical dispenser what strength to supply the lenses (or contacts). The power of the lenses necessary to correct your vision is measured in units called diopters which go up or down units of 0.25. Plano is the fancy term for 0.00, which means there is no refractive error. Most sunglasses off the shelf have plano lenses, and we might order a plano lens for a patient who has recently had cataract surgery on one eye, or somebody who wants to order coloured contact lenses.
This is how a script may look, for the ease of simplicity, I won’t go into astigmatism or axis.
+2.25 (right eye)
+2.50 (left eye)
-1.75 (right eye)
-2.25 (left eye)
The plus is used for people who are farsighted and the minus for people nearsighted.
Do cats develop refractive errors as they age?
There is very little information on refractive errors in cats. One small trial of 98 healthy cats did show refractive errors in cats and kittens. Younger cats had greater negative refractive errors (shortsighted) than adults but generally progressed to emmetropia (normal vision) during adulthood. Most adult cats are neither shortsighted or farsighted.
How cats see the world
Even cats who do have normal vision won’t have 20/20 vision in the way we do. Cats are not small people and their eyes have evolved for hunting in low light.
Cats have elliptical pupils which can expand considerably to let in more light from dusk to dawn
A greater number of cones which assist with peripheral and night vision but fewer rods than people means their ability to see colour and fine detail is limited.
The tapetum lucidum is a layer of reflective tissue which lies directly behind the retina and acts as a mirror to reflect light back through the retina. If the light misses a rod, it will reflect off the mirror layer of the tapetum lucidum and be bounced back, which provides the photoreceptor cells with a second opportunity for photon-photoreceptor stimulation, thereby enhancing visual sensitivity at low light levels.
The cat has a large lens which enables it to gather more light, but the cat’s lens is less able to change shape and focus over different distances than that of the smaller human lens which means that cats cannot see extremely close objects. The small human lens gives us a large depth of focus.
So, no glasses or contact lenses for cats?
While refractive errors are not common in cats, contact lenses do exist for cats with corneal ulcers. The contact lens (known as a bandage contact lens) goes over the cornea to relieve pain and allow the cornea to heal.
Vision loss in older cats
While refractive errors aren’t an issue in cats, vision problems can develop. The most common cause of vision loss is due to cataracts which occur when the normally transparent lens of the eye becomes opaque, which reduces the amount of light which reaches the retina. Cats of any age can develop a cataract, but they are most common in middle-aged to senior cats. Surgery may be recommended to replace the lens and replace it with an intraocular lens. Where surgery isn’t an option (due to the age of the cat, financial reasons) conservative management can include restricting the cat inside and maintaining a normal routine which includes avoiding moving things around. Cats adapt well to vision impairment.
Retinal detachment (RD) is a common, severe and sight-threatening disorder which occurs when the retina lifts or pulls away from the underlying retinal pigment epithelium due to a tear in the retina. This allows vitreous, a gel-like substance which gives the eye its shape to leak through the tear which causes the retina to separate from the underlying tissue. High blood pressure (often a side-effect of chronic kidney disease), hyperviscosity syndrome, glaucoma, advanced diabetes and trauma can all lead to a retinal detachment.
Tabby is a coat pattern and not a breed, it consists of four patterns, mackerel, spotted, classic and ticked. The background hair consists of light and dark bands, intermingled with dark lines, spots or swirls layered on top.
What colour is a tabby cat?
Tabby occurs in several colours, the most common are brown tabby, silver and orange tabby.
Tabby refers to a coat pattern in cats which consists of dark swirls, stripes, spots superimposed on a lighter background of ticked (banded fur).
The banded background (ground colour) consists of hairs which are more than one colour along the hair shaft and is termed agouti. This is caused by the transient inhibition of pigment production during, the hair’s growth.
The agouti gene controls whether the tabby pattern is expressed or not. The dominant agouti allele, with the symbol A will express the tabby pattern. The recessive a ‘hides’ the tabby pattern, to produce a solid (self) coat colour from the root of the hair to the tip. A cat must receive two copies of the recessive a gene (aa) to have a solid coat.
Three possible outcomes dictate if the coat will be tabby or not, remembering that the cat receives a copy of each gene from the mother and the father.
A/A (homozygous dominant) – Tabby
A/a (heterozygous dominant) – Tabby (the dominant A will override the recessive a)
a/a (heterozygous recessive) – Non-tabby (solid)
The tabby pattern is common in random-bred cats as well as many pure breeds. All domestic cats were once tabby, mutations lead to some cats appearing solid, bi-colour or pointed. Even cats with no tabby stripes have tabby genes but do not show the pattern on the fur. Some young cats with solid coat colours will display faint ghost tabby patterns until their fur becomes fully pigmented.
The basic wild-type tabby is a mackerel (Tm); however, two mutations have arisen, the dominant ticked tabby (Ta) and the recessive classic tabby (tb).
Basic cat genetics
Cats have 19 chromosomes which come in pairs, one from the mother and one from the father. 18 of the chromosomes are autosomes, and one pair are the sex chromosomes X and Y. All of the female cat’s eggs are X, whereas the male sperm can be X or Y. If an X sperm fertilises the egg, the offspring will be female (XX), if a Y sperm fertilises the egg, the offspring will be male (XY).
Genes are contained within the chromosome which is made up a double-strand helix containing DNA. DNA contains the instructions necessary for the cat to develop, survive and reproduce. For this to occur, the DNA has to be converted into messages which can be used to produce proteins, that are complex molecules that do most of the work within the cat’s body.
A locus (plural loci) is the specific, fixed position on a chromosome where a particular gene or genetic marker is located.
Alleles are variants of the same gene, for example, B (black), b (chocolate) and b1 (cinnamon).
The tabby coat occurs in many colours, primarily silver, brown and red (ginger/yellow). But a dilution can change those primary colours into lighter forms.
Melanocytes are cells responsible for producing melanin, which are microscopic granules occurring in the hair, skin, and iris of the eyes. The size, shape and arrangement of melanin granules are responsible for the colour of the cat’s coat. Cats have two types of melanin, black-based eumelanin and orange-based pheomelanin. Eumelanin are spherical and absorb almost all light, which gives black pigmentation, pheomelanin granules are elongated and produce the red coat colour.
The black gene has three alleles which control the density of eumelanin in the hair shaft.
B produces black fur and is dominant
b reduces melanin density to a chocolate colour
b1 which further reduces melanin density to a medium brown (cinnamon)
Red based colours have two alleles which are located on the X chromosome.
O produces red fur
o (non-orange) produces black fur
Dilute classic tabby munchkin cat[/caption]
Dilute coat colours are a recessive trait which dilutes coat colours by causing uneven distribution of pigment in the hair shaft
Black dilutes to blue (grey)
Chocolate dilutes to lilac
Cinnamon dilutes to fawn
Orange dilutes to cream
Dilute modifier (DM)
A secondary type of dilution known as dilute modifier can also occur, which causes the coat to take on a brownish cast. The dilute modifier only affects dilute colours and has no effect on dense colours.
Blue becomes caramel
Chocolate becomes taupe
Cream becomes apricot
White spotting gene
Some tabby coats have some white fur, usually on the paws, belly, chest, throat and sometimes face. This white fur is caused by the white spotting gene (S). Genetically, the cat is tabby, but the white spotting gene masks the colouration on certain parts of the body.
Also known as striped, the mackerel tabby pattern is the dominant wild-type which consists of well-defined, evenly spaced thin vertical stripes on the sides of the body which extend from the shoulder to the tail, and a paler ground colour.
The spotted coat is a variant of the mackerel tabby however a modifier gene breaks the characteristic mackerel stripes up into spots.
Also known as blotched or marbled, the classic tabby coat pattern consists of dark whorls on a lighter background. The ideal classic tabby will have a bullseye or oyster mark on each flank. The classic tabby is recessive to the mackerel tabby.
When viewed from above, the shoulders of a classic tabby have the appearance of a butterfly, and the classic is sometimes referred to as a butterfly tabby.
Also known as Abyssinian tabby, the ticked tabby has a gene which hides the tabby striping, leaving only the underlying agouti colouration. There is little to no striping on the body, but some faint fine barring may be present on the face, legs and tail, this may be more apparent if the cat is heterozygous, meaning its genetic makeup is Ta/Tmor Ta/tb
All tabby cats, regardless of pattern or colour, have a characteristic M on their forehead and most will have additional lines around the eyes. The ticked Singapura has cheetah lines, which extend down the face from the inner corner of the eyes.
What cat breeds can have the tabby coat pattern?
Siamese (lynx point)
Do tabby cats have striped skin?
Tabby cats do not have striped skin, interestingly, tigers do.
Are tabby cats a breed?
Tabby is a pattern and not a breed of cat.
Is the tabby gene dominant?
The tabby pattern is dominant over solid.
Are tabby cats male or female?
The tabby pattern can be found on both male and female cats, however, the ratio of ginger males to females is 3 -1. That is because the female must inherit the red gene from both mother and father for her to be ginger, if she inherits one red gene and one black gene (or brown), she will be tortoiseshell. Some females also carry the white spotting gene, which will make her a calico or a torbi. Tortoiseshell and calico cats have a solid colour (usually black), intermingled with red, others show both brown tabby and red tabby.
Why does the female have two tabby colours but not the male?
The female inherits a copy the red gene located on the X chromosome from one parent and a non-red gene from the other parent. X-inactivation or lyonization occurs during early development (around the eight-cell stage, but it can occur later) to prevent the expression of both X chromosomes. Every cell in the female has one active and one silenced X chromosome (known as a Barr body), and as the cells continue to divide, they will take the colour from those eight progenitor cells. The earlier the inactivation, the larger the patch of fur derived from each lyonized progenitor cell.
Below is a photo of a calico cat, you can clearly see the brown and red tabby colours as well as the effects of the white spotting gene. Tortoiseshell and calico are rare in male cats because they only have one X chromosome, so they will either be ginger or non-ginger. Occasionally a male will be calico or tortoiseshell, the incidence is reported to be 1 in 3,000, these males are almost always infertile.
For many, part of the enjoyment of Christmas is time spent with family and friends over Christmas lunch or dinner. As pet owners, we want to include our cats in the festivities, but not all food is safe for cats to eat. We take a look at common Christmas foods which are safe or dangerous for cats.
When it comes to food, moderation is the key. Treats should make up no more than 10% of a cat’s diet as they are not complete and balanced and many contain empty calories.
A cat’s tail can tell us a lot about how the cat is feeling and is a valuable communication tool not only between cats but also to communicate emotions to humans.
Paying attention to the cat’s tail is just one part of a larger picture. The position of the body, eyes and whiskers, as well asvocalisations(meowing,hissing, purring, chirping), are also important clues as to how the cat is feeling.