This is a continuation of the series about feline genetics. If you haven’t read part 1, click here! In this post, I will be covering the remaining coat patterns: tortoiseshell, calico, and color-point as well as some other miscellaneous facts!
Tortoiseshell cats, also affectionately named “torties”, have a consistent mix of orange/red and black, creating a unique coat unlike the ticked tabby pattern. The patches can range from being very mingled or they may be more distinct blocks of color. Other types of tortoiseshell cats include the “blue-cream” (also known as the blue tortie) is randomly patched all over with blue and cream. It is the dilute version of the more common red and black coat. Another is the “brown patched tabby” looks almost like autumn leaves, covered with patches of brown tabby and patches of red tabby. This color is often called the “torbie” because it is a tabby tortie.
Not only can the colors of the tortoiseshell cats vary between each individual cat, but the patterns of the colors can as well. In general, there are two main patterns: brindled and patched. Brindled patters give a more fluid appearance, as the colors are woven together. Patched patterns feature solid patches of the black or red hair.
A rare and little-known marbled cat possesses an unusual mixture of small and big cat characteristics. It is primarily thought to be an inhabitant of moist tropical forest but its specific habitat requirements are poorly known, with only anecdotal information available. It has been reported in mixed deciduous-evergreen forests and secondary forests as well as other habitats from sea level up to 10,000 feet (3,000 meters) above sea level.
Reports have shown that the marbled cat’s range can be from northern India and Nepal, through south-eastern Asia, to Borneo and Sumatra. This distribution includes areas of northern India, Nepal, Sikkim, Assam, Myanmar, Laos, Thailand, Vietnam, Cambodia, peninsular Malaysia, Sumatra, and Borneo. In the Malay area they are rare and confined to the mainland.
Felines come in many shapes and sizes. Well, maybe not as diverse as its fellow rival the dog, but cats do have an extensive range of colors and patterns. And it’s all thanks to genetics. This is the first installment of a three part series.
In general, there are six basic patterns, or combinations of colors in a specific layout: solid, tabby, bi-color, tortoiseshell, tricolor, and color-point. This post will cover the first three patterns.
The easiest one to recognize is the solid pattern, which is, for the most part, a single-colored coat that is evenly distributed all over the body. It is key that a solid-colored cat has no recognizable stripes, spots, ticking, patches, or shading. For example, a “solid-blue” cat or a “maltese” is blue-gray all over, whether it may be a dark slate gray, a medium gray, or a pale ash gray. Or, a “solid-black” cat is black all over and includes shades such as coal black, grayish black, or brownish black. (Fun Fact: Black cats can “rust” in the sunlight; the coat will turn into a lighter brownish shade.)
Cat paws are amazing and despite our curiosity to touch, cats are quick to shy away. This is because their paw pads are exceptionally sensitive and packed with receptors because they are vital to feline’s survival and hunting skills.
They also function as shock absorbers and to help regulate body temperature. Paw pads are soft and cushion-like, with one in the center of the paw and at the tips of each toe. They provide cushion when running and the ridges may provide traction. These are extremely useful characteristics when hunting as the cat may need to sprint suddenly to surprise its prey.
Furthermore, it is also known for cats who live in extreme climates like the snow leopard have fur-covered foot pads to insulate the bottom of their feet because the paw pads are so sensitive to temperature, pain, and pressure. The pads themselves are not insulated and can be severely injured by hot pavements, frozen sidewalks, and ragged surfaces.
Felines possess many physiological attributes that give them their astounding athletic abilities. But one of their most prominent characteristic that all cats share that helps them maneuver gracefully is the whiskers. They have about 24 movable whiskers on their muzzle, twelve on either side of the nose, arranged in four rows in a pattern as individual as our fingerprints. There are also small groups of whiskers situated on other parts of the body as well: high on the outer edges of the cheeks, and above the eyes.
Shorter whiskers, also known as tylotrich, are specialized hair for sensation and are the large single hairs scattered over the skin and body acting like short whiskers. One example of where the tylotrich can be located are on the back of the front legs. There are many throughout the cat’s body but outside of the knowledge we have for whiskers, little is known about how these are used.
A common mistake people make is assuming that cat whiskers and human hair are alike. However, the facial whiskers, unlike human hair, are actually touch receptors and are twice as thick as the hair on its coat. They are also known as vibrissae, embedded more deeply in the cat’s body than the shorter top-fur coat, are connected to the sensitive muscular and nervous systems under the skin. Being connected to muscle, the whiskers can be moved backwards and forwards at will.
Based on past posts, it seems logical to assume that cats have extremely fine tuned and heightened senses compared to those of humans. Their sense of balance, hearing, smell, and vision (to some extent) is better than what humans could be. However, one sense that falls short of a human’s is a cat’s sense of taste. Humans have approximately 9,000 taste buds compared to the paltry 470 of a feline’s.
A Feline’s Sense of Taste
The tongues of most mammals hold taste receptors, proteins that bind to incoming substance. These receptors are attached to what is known as gustatory cells which are scattered all over the tongue. Through their pores, the cells send filaments to the outside which collect and transmit tastes to the underlying nerves. On a side note, these nerve fibers will also respond to thermal stimuli in addition to taste. Prolonged cooling of the tongue with ice water was found to abolish all responses to gustatory stimuli.
Like humans, cats are responsive to four basic tastes: sour, bitter, salty, and sweet, decreasing in sensitivity in that order. But felines have evolved to exclusively eat meat and as such, sugar and carbohydrates (which is turned into sugar) means very little. As such, they lack the sweet receptor, which is made up of a coupled protein generated by two separate genes known as Tas1r2 and Tas1r3, and the necessary conduction fibers in the glossopharyngeal nerve from the tongue to the cerebrum which is required to taste sweetness. As obligate carnivores, their response to sweet is much weaker, almost non-existent in comparison to other mammals.
Many people will observe that their cats are attracted to sugary processed foods like candies, ice cream, pudding, etc. This might seem that their cats have a “sweet tooth” but in reality, it is probably because the fat content, which they can easily detect, is what attracts them.
These rare, beautiful gray leopards live in the mountains of Central Asia. The populations are extremely fragmented throughout the harsh, remote, mountainous regions, with the majority of snow leopards located in the Tibetan region of China. Generally found at elevations between 1,000 to 1,500 feet (3,000 to 4,500 meters), snow leopards thrive in the alpine and subalpine ecological zones where it frequents the steep terrain broken by cliffs, ridges, gullies, and rocky outcrops.
However, in some parts of Mongolia and on the Tibetan Plateau, they occur in relatively less precipitous landscape, especially if there are suitable travel routes along ridges and where sufficient cover is found. In the mountains of Russia and parts of Tian Shan, the snow leopard occurs in open coniferous forests, generally avoiding dense forests.
A snow leopard’s’ range accompanies 12 countries: Afghanistan, Bhutan, China, India, Kazakhstan, Kyrgyzstan, Mongolia, Nepal, Pakistan, Russia, Tajikistan, and Uzbekistan.
“Hearing is the cat’s second most important sense, which is one of the reasons blind cats can get around well.” – Dr. Weigner
A superior ability to detect sound helps the cat not only in locating prey but also detecting predators and navigating its environment. This skill is attributed to a cat’s ears, the paired receptor organs designed for the special senses of hearing and maintaining balance. The ears are located on both sides of the head, sitting above and behind the eyes. The external portion is identified as the pinnae but also consists of the middle and inner ear which are located internally.
Cats are very sensitive, with a range of hearing both above and below the range of frequencies that can be detected by humans. They can hear better than people and even better than most dogs. They are also able to accurately pinpoint the source of a sound. A cat up to 3 feet away from the origin of a sound can pinpoint its location to within a few inches in a mere 6/100th of a second. Not only are they accurate, they can also hear sounds at far greater distances – four or five times farther away than what humans can hear.
Eyes across all species serve for one purpose: sight. These globular organs sole function is to process light in order to create an image of the outside world. It is through vision that most animals are able to navigate the world and survive. Without it, survival may seem almost impossible unless other senses become more sensitive to bring in more information. Usually, this is not a problem as many species, including humans and cats, can function just fine with some little help.
The feline urinary system is one of the biological systems necessary to maintain the cat’s health. It works to maintain the proper amount of water in the body, as well as the body chemistry. Therefore, it has several important functions: gets rid of waste products created when food is transformed into energy, maintains the correct balance of water and electrolytes within the body’s cells, and processes vitamin D. The urinary system also produces the hormones erythropoietin and renin, which maintain healthy blood pressure, producing blood cells, and absorbing salt.
A cat’s urinary tract is a system made up of the kidneys, ureters (which connect from kidneys to bladder), the bladder, and urethra. These organs work together to produce, transport, store, and excrete urine.
The first major organ is the kidney. Like humans, cats have two kidneys located in the abdominal cavity under the backbone, close to where the last rib meets the spine. The indentation of the “bean” in the been-shaped organ is called the hilus. This is the area where the blood vessels, nerves, and ureters enter and leave the kidney.
When water and nutrients are absorbed into the bloodstream in the small intestine, the bloodstream takes the water to the kidneys for filtration. In the kidney, there are hundreds of nephrons, microscopic filtering units, that have the ability to form urine itself. Each nephron consists of a circular ball-shaped cluster of small blood vessels called a glomerulus and a renal tubule, a small tube. Once the unwanted substances are excreted in the urine, the rest, such as water and certain salts, are returned to the bloodstream.
By regulating fluids, kidneys regulate the acid-base balance of the blood and blood pressure. This keeps the feline’s body chemistry in balance while it removes toxins. The kidneys also monitor and maintain the balance of body water, ensuring that body tissues receive enough water to remain hydrated and function properly.
To move the liquid waste products, the ureters, two small tube-like organs, connect the kidneys to the bladder.
The bladder is a collapsible muscular organ shaped like a balloon. It is also located in the abdomen just in front of the pubic bone of the pelvis, held in place by the ligaments in the region. The bladder functions as a means for temporary urine storage.
A circular muscle called a sphincter controls the outlet opening of the bladder, keeping the urine from leaking out. Once the bladder reaches a certain point of distention, nerves in the bladder wall notify the brain to empty the bladder. When
appropriate, the animal will voluntarily relax the sphincter to release the urine, which will enter the urethra to be carried outside the body.
Diseases and Disorders of the Urinary System
A well balanced diet is important to keep the urinary system healthy. An improper diet can lead to urinary tract problems such as struvite crystals. Struvite crystals are comprised of magnesium, and phosphorous, and may collect in the bladder or within the urethra, where they block the urinary pathway.
Feline lower urinary tract disease (FLUTD): It is a common disorder seen in both male and female cats. The exact cause is unknown but it may be influenced by bacterial or viral infections as well as certain dietary factors. FLUTD is characterized by painful urination with or without the presence of blood. It is very uncomfortable and can be life-threatening. Also known as feline idiopathic cystitis (FIC) and feline urologic syndrome (FUS).
Pyelonephritis: This refers to infections of the kidney due to bacteria. It may also be secondary to severe, chronic, or recurrent bladder infections. With time, the bacteria associated with bladder infections may travel up the ureters to infect the kidneys.
Urinary tract stones: Most commonly found in the bladder, these stones are a buildup of calcium deposits. Symptoms are similar to cats with FLUTD and treatment varies on the type number, and location of the stones.
Kidney failure: This disease results when the kidneys are not able to remove toxins from the body or can no longer regulate water and electrolyte balance. Cats can lose up to ⅔ of their functional kidney capacity without signs of kidney failure. After ¾ of the capacity is gone, toxins and abnormal levels of minerals and electrolytes begin to build up in the blood stream. Can be acute, caused by obstruction of the lower urinary tract followed by exposure to toxins, or chronic kidney failure, due to degeneration and deterioration.
Tumors: It is relatively rare for tumors to occur in the urinary tract for cats. The most common urinary tumor is lymphosarcoma of the kidneys, which affects both kidneys at the same time.
Trauma: Fractures of the pelvis may cause disruption in the urethra and/or the bladder. Fractures of the spine and tail may result in paralysis of the bladder. Hemorrhages or rupture of the kidneys, ureters, or bladder may also occur with trauma to the abdomen.
Just like humans, cats reproduce sexually between two partners, a male and female. Both genders have their own set of reproductive system, In male cats, the genital tract provides the pathway for semen, which contains the sperm cells. In female cats, the genital tract includes both the ovaries, which contain the egg cells, and the womb, which will carry and nurture the young as they develop.
The penis is the male copulatory organ. It contains vessels and connective tissue specialized to produce an erection, which facilitates penetration of the penis into the vagina of the female. The tip is called the glans and is covered with 120 to 150 penile spines, directed backward. These spines appear at about 12 weeks of age and are fully developed at puberty. They are absent in neutered male cats, disappearing by six weeks after castration.
It is located within the prepuce, which acts as a moist protective covering for the non-erect penis, and not erect, it is only visible on the posterior of the body.
The scrotum is located beneath the anus and only visible when the tail is lifted upwards. It is a pouch divided by a thin wall into two cavities, each of which is occupied by a testicle, an epididymis, and the tail end of the spermatic cord. The layer underneath the skin is called the dartos, a layer of tissue that is made up of muscle and connective tissue.
Because of its location and lack of fact, the scrotum functions as a temperature regulator for the testicle and epididymis. The temperature within the scrotum is generally several degrees lower than the abdomen. This lower temperature is essential for the normal manufacturing and maintenance of sperm.
The testicles perform two major functions: production of sperm and testosterone. Each contain seminiferous tubules that manufacture sperm. Special cells near the tubules called sertoli cells support and supply nutrition to the sperm cells.
The epididymis is an enlarged tube positioned along the edges of the testicle. It consists of an elongated structure composed of a long convoluted or twisted tube. They are the organs where sperm are stored and are used to slowly transport sperm to the ductus deferens. The length of the epididymis and the slow transport of sperm are important in allowing the sperm time to become mature.
The ductus deferens or vas deferens begins at the tail of the epididymis and runs along the border of the testicle. The sperm is transported through the ductus deferens towards the back of the abdomen, passes through the prostate, and empties into the urethra. The ducts are thin muscular tubes that are made up of three layers of muscle.
The prostate gland is very small in the cat. It is normally located near the front of the rim of the pelvis, surrounding the beginning of the urethra as well as the end of the ductus deferens. This organ has multiple openings into the urethra. It is a relatively unimportant organ in the male cat.
Diseases and Disorders of the Male Feline Reproductive System
Cryptorchidism: This refers to the failure of one or both testicles to descend into the scrotum by seven to eight months of age. The undescended testicle is often retained within the abdomen. Because of the temperature of an undescended testicle is higher than normal, it usually causes infertility.
Monorchidism: It is a rare developmental condition in which the affected individual usually develops one testicle. It is caused by genetic abnormality.
Trauma: It may occur to the scrotum, prepuce, and urethra. Includes injuries from automobile accidents, bite wounds, and sharp objects.
Female Reproductive Organs
The female cat’s reproductive tract consists of the female genital organs including the ovaries, uterus, vagina, vulva, and mammary glands. It is responsible of producing and storing egg cells as well as where the embryo develops. Like the male, the reproductive organs are located in the abdomen.
Mammary glands are located in two rows along the outside of the abdomen, running from the groin to the chest. They are composed of connective tissue to provide support, structure, blood vessels, lymphatic vessels, and glandular tissue. Each gland stores and secretes milk. Usually, a cat has four pairs of mammary glands.
Ovaries are located just behind the kidneys and contain the eggs that are waiting to be fertilized. They are suspended from the top of the abdomen by a broad ligament called the suspensory ligament. Other than storing the eggs, the ovaries also produce the female hormones estrogen and progesterone. To connect the ovaries to the uterus are the oviducts or the fallopian tubes. Where the ovaries and oviduct connect is a funnel-like structure, the infundibulum, which catches the egg when it is released from the ovary.
The uterus of the cat is Y-shaped, with the arms, called horns, of the “Y” being longer than the stem, also known as the body. The uterine horns extend from each ovary to join together to form the body of the uterus. The walls are lined with a vascular and glandular lining (mucosa) and contains smooth muscle. The muscular substance of the uterus is called the myometrium; the inner lining is called the endometrium.
It serves as the site for implantation of fertilized eggs and for the growth and development of the fetus. When the female is pregnant, the fetuses are arranged in a row in both horns.
Where the uterus ends, the cervix begins. It contains connective tissue and muscle that form a firm tube-like sphincter. It is usually closed to prevent infection. Only during fertilization and birth is the sphincter of the cervix relaxed or opened.
The cervix separates the uterus from the vagina, which passes through the pelvis. The vaginal walls are made up of an inner mucosal layer, a middle smooth muscle layer, and an external coat of connective tissue. The vaginal mucosa contains numerous folds, which allows for expansion and stretching. It provides a protected passage for fetuses to move from the uterus to the outside and protects the opening of the urethra, where urine leaves the body.
The opening of the vagina is protected by the vulva. It also provides external markings that identify the feline as a female.
When a cat is spayed, the ovaries, oviducts, and uterus are removed.
Diseases and Disorders of the Female Feline Reproductive System
Ovarian cysts: Cysts may develop from the accumulation of fluids within the follicles. There may cause no clinical signs but the animal may fail to come into estrus (heat) or show signs of continuous estrus.
Ovarian remnants: This may sometimes occur when a portion of the ovary is cut and left behind during the spaying surgery. Cats show recurrent signs of coming into heat even after the surgery has been performed.
Metritis: It is the inflammation of the uterus, usually used when uterine inflammation develops after a pregnancy. This develops because of a bacterial infection that ascends up the vagina and enters the uterus through the open cervix.
Mucometra: This disease usually occurs in older female cats that have not been spayed. The glands and the endometrium of the uterus become enlarged and will sometimes produce large amounts of mucus. The source is usually bacteria entering the uterus through the cervix. Discharge may drain if the cervix is open. If closed, no discharge is seen.
Uterine prolapse: It is the protrusion of the uterus through the cervix into the vagina. Portions may be exposed at the vulva, usually during or immediately after giving birth or spontaneous abortion.
Vaginitis: It is the inflammation of the vagina. It can occur in any age of the cat and in both spayed and intact females. Causes include congenital defects, urinary tract infections, bacterial and viral infections, tumors, and trauma. The primary clinical sign is vaginal discharge.
Galactorrhea: This disease occurs when milk production occurs outside of pregnancy.
Agalactia: It is the failure to secrete milk at appropriate times.
Galactostasis: This is the abnormal collection of milk in the mammary glands.
Mastitis: This disorder is the inflammation and/or infection of the mammary glands. In most cases, it is believed that the bacteria travel up the mammary ducts into the glands, which then become painful, red, and sometimes, swollen.
Tumors: Can develop all along the feline reproductive tract. Spaying prevents the development of tumors.