A
Gerbil is a small mammal of the order
RodentRodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
ia. Once known simply as "
desert rats", the gerbil subfamily includes about 110 species of
AfricaAfrica is the world's second-largest and second most-populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area. With a billion people in 61 territories, it accounts for about 14.8% of the...
n,
IndiaIndia, officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the south, the Arabian Sea on the west, and the Bay of Bengal...
n, and
AsiaAsia is the world's largest and most populous continent, located in the eastern and northern hemispheres. It covers 8.6% of the earth's total surface area and with approximately 4 billion people, it hosts 60% of the world's current human population.Asia is traditionally defined as part of the...
n rodents, including sand rats and
jirdMeriones is a rodent genus that includes the gerbil most commonly kept as a pet, Meriones unguiculatus. The genus contains most animals referred to as jirds, but members of the genera Sekeetamys, Brachiones, and sometimes Pachyuromys are also known as jirds. The distribution of Meriones ranges...
s, all of which are adapted to arid habitats. Most are primarily diurnal (though some, including the common household pet, do exhibit
crepuscularCrepuscular is a term used to describe some animals that are primarily active during twilight, that is at dawn and at dusk. The word is derived from the Latin word crepusculum, meaning "twilight." Crepuscular is thus in contrast with diurnal and nocturnal behavior. Crepuscular animals may also be...
behavior), and almost all are
omnivorousOmnivores are species that eat both plants and animals as their primary food source...
.
The word "gerbil" is a diminutive form of "
jerboaThe jerboa form the bulk of the membership of the family Dipodidae. Jerboas are jumping desert rodents found throughout Asia and Northern Africa.- Characteristics :...
", though the jerboas are an unrelated group of rodents occupying a similar
ecological nicheIn ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different school if the members of these schools utilize significantly different...
.
One
MongoliaMongolia is a landlocked country in East and Central Asia. It borders Russia to the north and the People's Republic of China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only 24 miles from Kazakhstan's eastern tip. Ulan Bator,...
n species,
Meriones unguiculatusMeriones unguiculatus, the Mongolian Jird or Mongolian Gerbil is a rodent belonging to subfamily Gerbillinae. It is the most widely known species of the Gerbil subfamily, and is the usual gerbil species to be kept as a pet or experimental animal, when it is known as the Domesticated Gerbil...
, also known as the Clawed Jird, is a gentle and hardy animal that has become a popular
petA pet is an animal kept for companionship and enjoyment or a household animal, as opposed to livestock, laboratory animals, working animals or sport animals, which are kept for economic reasons. The most popular pets are noted for their loyal or playful characteristics, for their attractive...
. It was first brought from China to Paris, France in the nineteenth century, and became a popular house pet. It was then brought to the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
in 1954 by Dr. Victor Schwentker for use in research.
Gerbils are typically between six and twelve inches (150 to 300 mm) long, including the tail which makes up approximately one half of their total length. One species however, the
Great GerbilThe Great Gerbil is a large gerbil found throughout much of Central Asia.-Characteristics:The largest of the gerbils, Great Gerbils have a head and body length between 15-20cm. Their skulls are distinctive by having two grooves in each incisor. They have large front claws used for burrowing.The...
, or
Rhombomys opimus, originally native to
TurkmenistanRepublic of Turkmenistan is a country in Central Asia. Until 1991, it was a constituent republic of the Soviet Union, the Turkmen Soviet Socialist Republic...
, can grow to more than 16 inches (400 mm) in length. The average adult gerbil weighs approximately 2 1/2 ounces. As of August 19, 2003, officials in western
ChinaChina is a cultural region, an ancient civilization, and, depending on perspective, a national or multinational entity extending over a large area in East Asia....
's
Xinjiang Uygur Autonomous RegionXinjiang is an autonomous region of the People's Republic of China and also claimed by the territory of the Republic of China.-Names:Older English-language reference works often refer to the area as Chinese Turkestan, Sinkiang, East...
began releasing
eagleEagles are large birds of prey which are members of the bird family Accipitridae, and belong to several genera which are not necessarily closely related to each other. Most of the more than 60 species occur in Eurasia and Africa...
s to combat the damage they say the great gerbils have done to eleven million acres (46,000 km²) of grassland.
Gerbils as pets
Gerbils were first introduced to the pet industry in 1964. These were the
MongoliaMongolian may refer to:* Something of, from, or related to Mongolia, a landlocked country in East and Central Asia that borders Russia to the north and People's Republic of China to the south, east and west....
gerbils. Their value as pets was soon appreciated and they are now found in pet shops all over the UK and USA.
Due to the threat they pose to indigenous ecosystems and existing agricultural operations, it is illegal to purchase, import, or keep a gerbil as a pet in the U.S. state of
CaliforniaCalifornia is the most populous state in the United States, and the third largest by area. California is the second most populous sub-national entity in the Americas, behind only São Paulo, Brazil...
.
Life in the desert
The typical Mongolian gerbil is a desert species, and lives underground in a network of tunnels, which include chambers with families. Adults move away and meet others from other chambers, extend the network, create their own chamber, and breed. Gerbils come up for food and water; there is no evidence of hoarding food, but gerbils will eat a lot of fatty foods in one sitting, suggesting supplies in the form of fat reserves rather than food storage. Gerbils do not hibernate and are diurnal. Their long tails help them to balance when they stand up on their hind legs.
Gerbil movement is more like hopping than running, and their large back feet are furry on the bottom to protect them from the heat of the sand. Gerbils are fast but overly inquisitive. In their natural environment, they are mostly
insectivoreAn insectivore is a type of carnivore with a diet that consists chiefly of insects and similar small creatures.Although individually small, insects exist in enormous numbers and make up a very large part of the animal biomass in almost all non-marine environments...
s, and additionally gain moisture from desert plants that store water in them. A gerbil has fur all over its body, including the tail, as this prevents it from getting sunburned.
Behavior
General gerbil behavior
Normal gerbil behavior includes jumping, climbing, chewing, and digging. The digging motions are very common: the gerbil moves its arms rapidly.
They are curious and not easily startled. They love to burrow and hide.
Gerbils are social animals, and live in groups in the wild. Often very large groups live well together, as long as the living environment is big enough. If it is not big enough, the gerbils may become frustrated and attack one another. Groups of females are much more quarrelsome than groups of males, but if fighting occurs among males it is usually much more vicious. Males will very rarely attack females.
Habits
Gerbils are not naturally aggressive creatures; much like hamsters, they would rather nibble a potential source of food and only fully bite when threatened. Gerbils do not make noises often, although some gerbils can squeal when scared. To communicate with other members of the species they 'thump' repeatedly using their back legs. This is often seen when a gerbil is frightened to warn other gerbils of the danger.
Food
Sunflower seedBotanically speaking, a sunflower seed is an achene. When dehulled, the edible remainder is called the sunflower kernel.For commercial purposes, sunflower seeds are usually classified by the pattern on their husks. If the husk is solid black, the seeds are called black oil sunflower seeds. The...
s, pumpkin seeds, and
peanutThe peanut, or groundnut , is a species in the legume family native to South America, Mexico and Central America. It is an annual herbaceous plant growing 30 to 50 cm tall...
s are favorites of most gerbils, though they have individual preferences and too many sunflower seeds may result in illness. They also enjoy fruits and vegetables such as
carrotThe carrot is a root vegetable, usually orange, purple, red, white, or yellow in colour, with a crisp texture when fresh. The edible part of a carrot is a taproot...
s or
appleThe apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family Rosaceae. It is one of the most widely cultivated tree fruits...
and even fruit peels such as that from a
bananaBanana is the common name for a herbaceous plants of the genus Musa, and the commonly eaten fruit it produces. They are native to the tropical region of Southeast Asia, and are likely to have been first domesticated in Papua New Guinea. Today, they are cultivated throughout the tropics.Banana...
. In fact, gerbils will eat almost anything:
dog biscuits and chewsDog food is food intended for consumption by dogs or other canine. Special types of dog food, given as a reward, and not as a staple, are known as dog treats....
; rat food; rabbit food; guinea pig food;
oatThe common oat is a species of cereal grain grown for its seed, which is known by the same name . While oats are suitable for human consumption as oatmeal and rolled oats, one of the most common uses is as livestock feed. Oats make up a large part of the diet of horses and are regularly fed to...
s; and various "special" treats from pet shops. Most weeds dubbed as safe for grazing animals like rabbits or guinea pigs can be eaten by gerbils as well. Pet gerbils will especially enjoy live
cricketCrickets, family Gryllidae , are insects somewhat related to grasshoppers and more closely related to katydids or bush crickets . They have somewhat flattened bodies and long antennae. There are about 900 species of crickets...
s,
grasshopperThe grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as short-horned grasshoppers...
s, and
locustLocust is the swarming phase of short-horned grasshoppers of the family Acrididae. The origin and apparent extinction of certain species of locust—some of which reached 6 inches in length—are unclear....
s as food, tearing the insect apart and eating the juicy insides.
Avoid
lettuceLettuce is a temperate annual or biennial plant of the daisy family Asteraceae. It is most often grown as a leaf vegetable. In many countries, it is typically eaten cold, raw, in salads, sandwiches, hamburgers, tacos, and in many other dishes...
s, as the nitrates can prevent oxygenation of the blood, and citrus fruits. Sugary treats are bad for gerbils; they rot the teeth and the sugar is hard for a gerbil to digest. Lastly, do not feed your gerbils food with high water content, such as
celeryApium graveolens is a plant species in the family Apiaceae commonly known as celery or celeriac depending on whether the petioles or roots are eaten.- Taxonomy :...
or
watermelonWatermelon refers to both fruit and plant of a vine-like herb originally from southern Africa and one of the most common types of melon...
, as the water will cause the gerbil to have the runs, or "wet-tail" as it is commonly known.
Drink
Although gerbils can go without
waterWater is an ubiquitous chemical substance that is composed of hydrogen and oxygen and is essential for all known forms of life.In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71%...
for a few days, provided they have plenty of moist food, they will always take water if it is available.
Cleansing
Gerbils do not need water to get clean — what cleans them is a sand bath. When taking gerbils out for exercise, a small basin of cool sand will be much appreciated, and true to instinct, a gerbil will roll over in the sand. The effect is instantaneous — their fur becomes much smoother and shinier.
Gerbil social behavior
Gerbils often have what looks like boxing matches; this is most common amongst young gerbils (gerbil "pups"). These are gentle play fights which usually end in the winner pinning down the loser and grooming it. However, if a pair of gerbils are fighting closely in a ball shape, with both gerbils biting deeply and drawing blood, careful but swift intervention is in order by the pet owner, using a jar or oven mitts to avoid getting bitten.
Gerbils like to sleep in a group, often on top of each other. Sometimes they will absentmindedly groom each other when half asleep. Gerbils have a form of purring called "bruxing" which they do when they are being groomed or while they enjoy being stroked in the hand by their owner.
Squeaks can occasionally be heard from them, and a squeak is usually an indication of annoyance. When another gerbil steps on another without thinking, it will give a squeak, or when a gerbil tries to steal another's food, it will turn with a squeak, and when a male tries to mate an unsuspecting female, she may well turn around sharply to face him and squeak at him. Gerbil pups will squeak more often when very young, sometimes when feeding or if they have strayed from the nest.
Gerbils will raise their hackles and arch their backs to show aggression, often turned to the side and leaning against the other gerbil's body. Usually this is a warning that a fight is about to occur, and if this behavior is observed it is wise to quickly intervene.
Gerbils will also alert each other to danger by thumping on their hind legs, usually triple thumps repeated in a steady sequence. Gerbils will also thump when sexually excited. Younger gerbils are more likely to start thumping than older ones.
Fighting
Gerbils, when fighting, may chase each other around frantically, amid small screams of protest by the victim. This is usually a case of bullying by one gerbil. If the feeling is mutual, the gerbils will stare each other down, pounce on one another and clamp their teeth around each other's neck, faces, or such in an attempt to draw blood. Gerbils can injure each other seriously in this way. Gerbil fighting is very loud and may last a long time. Gerbils often fight on their hind legs swiping at their opponent with their forepaws. Gerbils fighting will usually be on top of each other, rolling over and over rapidly. If gerbils are left to resolve the dispute, they will most likely fight to the death. A lead up to a fight can include chasing, persistent sniffing and following, and one gerbil forcing another to stay in a single area. A defeated gerbil will often be quiet for some time and remain in a single area. They will very likely stay away from their attacker for some time unless they attack it again. If the fight turns into a chase, the gerbil chasing will most likely try to bite the legs and tail of the opponent.
Mating
Gerbils will mate for several hours, in frequent short bursts followed by short chases where the female allows the male to catch her. Once he catches her, the female will squeak and make flick motions to get the male off her. Males will not attack females except in rare circumstances which may also include them having been separated from their original mates, or widowed. A female may attack a male, but usually he is more than a match for her.
Baby stages
When first born, gerbil babies are blind, deaf, hairless, and helpless. They drink their mother's milk. The young squeak softly when feeding and being picked up. Eventually they grow bigger, and within a week, they will begin to show skin
pigmentA pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
, indicating their possible fur color and markings. Soon after this, a thin downy fur will grow on them, and they will begin to make their fast yet unsteady way out of the nest when the bed is disturbed. This survival technique helps the babies get out of harm's way in case of a territory invasion.
The fur will grow thicker and longer, and by three weeks some of them may have one of their eyes open. Around this point, they begin to be weaned, eating food and not relying so much on milk. At this point, it would help to provide a soft food like an oat and milk mixture for them. The gerbils will become more active and their tails will lengthen and give them more balance so they can stand upright. When fully weaned and beginning to play fight with one another, they will soon be ready to move away, if required.
A mother will often be stern with how quickly the babies are weaned if she is expecting a new litter. A less fertile mother may let her litter suckle for longer. Older mothers often do not have as good a milk supply, and need plentiful water available to replenish it.
A litter will be of about 4-8 gerbils on average, although losses due to runts, defects and infanticide, or occasional, unexplainable persecution from other gerbils sometimes make the eventual litter one or two short.
Reproducing
The most common ways of checking the sex of a young gerbil are:
1) Turning the gerbil over and checking the gap size between the genital organs of the gerbil. Female gerbils have a small gap between the two areas, while males have a much larger gap.
2) Although not always clear in childhood and adolescence, male gerbils have a fur covered bulge at the base of their tails, on their underside. This is their
scrotalIn some male mammals the scrotum is a protuberance of skin and muscle containing the testicles. It is an extension of the abdomen, and is located between the penis and anus. In humans and some other mammals, the base of the scrotum becomes covered with curly pubic hairs at puberty...
pouch. Females have smooth, round back ends.
Males are generally larger than females in adulthood, in length, height, and width. A gerbil can also be sexed by looking at its underside when it is a blind, deaf baby. There will be either a thick line in the middle of the stomach (the scent marker) if it is a male, or eight dots (four on the left side, four on the right) (soon to be teats) if it is a female. I have found that the best time & way of sexing baby gerbils is to wait until they are around a week to a week & a half old, (sometime before they get hair) the females will have tiny dents above the thigh area where the males do not. These dents are indeed teats. I've noticed the males also have these dents, but they lack the ones above the thighs.
Reasons for popularity
There are several reasons for the popularity of gerbils as household pets. The animals are typically non-aggressive, and they rarely bite unprovoked or without stress. They are small and easy to handle, since they are sociable creatures that enjoy the company of humans and other gerbils. Gerbils also have adapted their kidneys to produce a minimum of waste to conserve body fluids which makes them very clean with little odor.
The pets are incredibly industrious and will explore new environments, and they will build, construct, and enjoy elaborate networks of tunnels if given an environment that allows for it. This is easily observable as gerbils are active during all hours of the day, as opposed to the more nocturnal rodent pets. They can "recycle" everyday paper-based items, such as cardboard products like toilet paper tubes and brown paper bags, into toys and nesting material, chewing the material into small bits. If the chewed material is allowed to accumulate to a depth of 4-6 inches deep, they will tunnel through it.
Teeth problems
Misalignment of incisors due to injury or malnutrition may result in overgrowth, which can cause injury to the roof of the mouth. Symptoms include a dropped or loss of appetite, drooling, weight loss, or foul breath.
Trauma
Common injuries are caused by gerbils being dropped or falling, usually while inside of a "run-about ball", which can cause broken limbs or a fractured spine (for which there is no cure).
Neglect
A common problem for all small rodents is neglect, which can cause the gerbils to not receive adequate food and water, causing serious health concerns, including dehydration, starvation, stomach ulcers, eating of bedding material, and cannibalism.
Diarrhea
Diarrhea can occur, usually caused by a virulent strain of E. coli or Salmonella, which is most common among weaning gerbils (3–6 weeks). Symptoms include lethargy, thinness, increased irritability, hunched posture, fluid or bloody diarrhea, and a wet, soiled anal area and tail. It is treatable with antibiotics, yet the gerbil may remain a carrier of the germ and spread it to other uninfected gerbils. For this reason, a gerbil that has had diarrhea should not be chosen to breed with.
Epilepsy
Between 20 percent and 50 percent of all pet gerbils have the seizure disorder
epilepsyEpilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures...
. The seizures are caused by fright, handling, or a new environment. The attacks can be mild to severe but do not typically appear to have any long-term effects, except for rare cases where death results from very severe seizures.
Tumors
TumorA tumor or tumour is the name for a swelling or lesion formed by an abnormal growth of cells . Tumor is not synonymous with cancer. A tumor can be benign, pre-malignant or malignant, whereas cancer is by definition malignant....
s, both benign and malignant, are fairly common in pet gerbils, and are most common in females over the age of 2. Usually, the tumors involve the ovaries, causing an extended abdomen, or the skin cancer, with tumors most often developing around the ears, feet, mid-abdomen, and base of the tail, appearing as a lump or abscess. The scent gland (positioned on the abdomen) should be checked regularly, a veterinarian can operate on the lump where possible.
Tail sloughing
Gerbils can lose their tails due to improper handling, being attacked by another animal, or getting their tail stuck. The first sign is a loss of fur from the tip of the tail, then, the skinless tail dies off and sloughs, with the stump usually healing without complications.
Tyzzer's disease
The most common infectious disease in gerbils is
Tyzzer's diseaseTyzzer's disease is a contagious bacterial disease in rats, gerbils, raccoons and horses. It is caused by Clostridium piliforme, formerly known as Bacillus piliformis, a spore-forming bacterium....
, which is often caused by either stress or bacteria, and produces symptoms such as ruffled fur, lethargy, hunched posture, poor appetite, diarrhoea, and often death. It quickly spreads between gerbils in close contact.
Deafness and inner ear problems
A problem with the inner ear can be spotted by a gerbil leaning to one side quite obviously. The fluids in the ears affect balance. However, this does not appear to affect the gerbils too much, which have an aptitude of just getting on with things, and getting used to their conditions. Gerbils with "extreme white spotting" colouring are susceptible to deafness, this is thought to be due to the lack of pigmentation in and around the ear.
Extremes of temperature
As desert animals, it is easy to make the mistake that as gerbils are used to bitter cold in the night and boiling heat in the day, they can be left in direct sunlight or in subzero temperatures. This can cause damage to a gerbil. The reason they survive in the desert is because they take frequent shelter in their tunnels. Many gerbils living together and plenty of bedding helps gerbils stay warm. In heat, they will trample their bedding flat. Heat can make gerbils noticeably lethargic, so the choice of shade is important. They do sweat when very hot, and become thirsty more often than usual.
Respiratory problems
A dirty, feces and urine invested environment for a gerbil can be a problem. Ammonia will build up, and gerbils may have trouble breathing. In the wild, gerbils will dig more burrows when their current one is filthy, but in cages this cannot happen. Symptoms of a respiratory infection may include exhaustion,
apathyImage:Challenge_vs_skill.jpg|250px|Apathy in terms of challenge level and skill level. Clickable.|thumbpoly 66 7 211 9 285 189 254 234 67 152 Anxietypoly 221 7 428 7 351 188 296 187 294 188 Arousalpoly 439 7 583 7 584 149 388 236 360 194 Flow...
, and a strange clicking or wheezing noise. One way to help solve this problem is to give the gerbil
antibioticIn common usage, an antibiotic is a substance or compound that kills or inhibits the growth of bacteria...
s. Luckily, in the wild, this does not happen to gerbils.
Birth defects
Gerbils are quite hardy, and it is rare for them to get sick. Seizures are common. Direct inbreeding may produce blind or deaf young with short life expectancies, and missing limbs.
Swimming
Due to their small limbs, they suffer from an inability to swim well.
<-- Ref counts for whole "Health Concerns" section.
Captive-bred gerbil colors
There are many color varieties of gerbil available in pet shops today, generally the result of years of
selective breedingSelective breeding is the process of breeding plants and animals for particular genetic traits. Typically, strains which are selectively bred are domesticated, and the breeding is sometimes done by a professional breeder. Bred animals are known as breeds, while bred plants are known as varieties,...
.
There are over 20 different coat colors in the
Mongolian gerbilMeriones unguiculatus, the Mongolian Jird or Mongolian Gerbil is a rodent belonging to subfamily Gerbillinae. It is the most widely known species of the Gerbil subfamily, and is the usual gerbil species to be kept as a pet or experimental animal, when it is known as the Domesticated Gerbil...
, which has been captive-bred the longest.
Another species of gerbil has also been recently introduced to the pet industry: the
Fat-tailed GerbilPachyuromys duprasi is a rodent belonging to subfamily Gerbillinae. It is the only member of the genus Pachyuromys. These rodents are the most docile species of the Gerbil subfamily. Often called the Fat-tailed Gerbil or Duprasi Gerbil. Other common English names: Fat-tailed Jird, Fat-tailed Rat,...
, or duprasi. They’re smaller than the common Mongolian gerbils and have long soft coats and a short, fat tail, appearing more like a
hamsterHamsters are rodents belonging to the subfamily Cricetinae. The subfamily contains about 24 species, classified in six or seven genera....
. There is a variation on the normal duprasi coat which is more gray in color, which may be a mutation, or it may be the result of hybrids between the Egyptian and Algerian subspecies of duprasi.
White spotting has been reported in not only the Mongolian Gerbil, but also the Pallid Gerbil and possibly Sundervall's Jird.
A long-haired mutation, a grey agouti or chinchilla mutation, white spotting, and possibly a dilute mutation have also appeared in
Shaw's JirdShaw's Jird is a species of rodent in the Muridae family.It is found in Algeria, Egypt, Libya, Morocco, and Tunisia.Its natural habitats are arable land, pastureland, and rural gardens.-References:...
s, and white spotting and a dilute mutation have shown up in
Bushy-tailed JirdThe Bushy-tailed Jird is a species of rodent in the Muridae family. It is the only species in the genus Sekeetamys.It is found in Egypt, Israel, Jordan, Saudi Arabia, and Sudan.Its natural habitat is rocky areas....
s.
When attempting to choose the color of the gerbil, dominant genes and recessive genes must be taken into account, the most common agouti (brown) color being the dominant color.
Resources
- McKenna, M. C. and S. K. Bell. 1997. Classification of Mammals above the Species Level. Columbia University Press, New York.
- Musser, G. G. and M. D. Carleton. 1993. Family Muridae. Pp. 501–755 in Mammal Species of the World a Taxonomic and Geographic Reference. D. E. Wilson and D. M. Reeder eds. Smithsonian Institution Press, Washington D.C.
- Nowak, R. M. 1999. Walker's Mammals of the World, Vol. 2. Johns Hopkins University Press, London.
- Pavlinov, I. Ya., Yu. A. Dubrovskiy, O. L. Rossolimo, E. G. Potapova. 1990. Gerbils of the world. Nauka, Moscow.
- http://www.research.usf.edu/cm/CMDC/C111_Normative_Biology_Diseases_Gerbils_7_03.pdf
External links