Insects beetle larvae , caterpillars , and cockroaches and meat carrion may be taken when available. In human habitation, Mus musculus consumes any human food that is accessible as well as glue, soap, and other household materials.
Many mice store their food or live within a human food storage facility. House mice are eaten by a wide variety of small predators throughout the world, including cats , foxes , weasels , ferrets , mongooses , large lizards , snakes , hawks , falcons , and owls. House mice try to avoid predation by keeping out of the open and by being fast. They are also capable of reproducing very rapidly, which means that populations can recover quickly from predation. Where house mice are abundant they can consume huge quantities of grains, making these foods unavailable to other perhaps native animals.
House mice are also important prey items for many small predators. Domesticated forms and albinos have been developed which are commonly used as laboratory animals especially in medicine and genetics , and as pets. Mus musculus also has a small role as an insect destroyer, but this is minimal. House mice do not cause such serious health and economic problems as do Rattus norvegicus and Rattus rattus. Mice are agricultural pests in some areas, however, and they do consume and contaminate stored human food with their droppings.
They also destroy woodwork, furniture, upholstery, and clothing. In addition, they contribute to the spread of diseases such as murine typhus, rickettsial pox, tularemia, food poisoning Salmonella , and bubonic plague. Recent research has also shown that they carry a virus--the mouse mammary tumor virus MMTV --that may contribute to breast cancer in humans. Indik, et al. Commensal populations of Mus musculus are generally stable and densities can be as high as 10 mice per square meter.
In the wild, populations are less stable and densities may be less than 1 mouse per square meters. Overall, populations are flourishing and are in fact aided by human construction of houses, barns, and other structures. Mus musculus often refers to several fairly distinct kinds of mice. As many as seven separate species may be placed under Mus musculus , such as Mus domesticus , western European house mice, and Mus castaneus , southeastern Asian house mice.
The former refers to a genetic strain with inner ear defects, causing the mice to weave, turn in circles, and wobble when they walk. The latter refers to a pathological condition causing mice to twitter constantly with a "song" resembling that of a cricket. Sage, et al. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
In otherwords, Europe and Asia and northern Africa. In birds, naked and helpless after hatching. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria. Found on all continents except maybe Antarctica and in all biogeographic provinces; or in all the major oceans Atlantic, Indian, and Pacific. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a now extinct synapsid ancestor; the fossil record does not distinguish these possibilities.
Convergent in birds. Iteroparous animals must, by definition, survive over multiple seasons or periodic condition changes.
If the animal struggles or appears to be in respiratory difficulty withdraw the tube and begin all over again. Once the desired position is attained, inject the material and withdraw the syringe. Monitor the animal after the procedure to ensure that there are no adverse effects. Subcutaneous injections Subcutaneous injections are usually made into the loose skin over the neck or flank using a fine gauge needle.
Insert the needle mm through the skin before making the injection. Lack of resistance to the injection is indicative that you are in the right location. Check for leak back especially if a larger volume is injected. Intraperitoneal injections Intraperitoneal injections are usually made in the lower right quadrant of the abdomen. The mouse is restrained with its head tilted lower than the body to avoid injury to internal organs.
After swabbing the lower right quadrant with alcohol, a fine gauge needle is introduced slowly through the skin, subcutaneous tissue and abdominal wall. Withdraw the syringe plunger to ensure that you are not in the bladder or intestines. If nothing is withdrawn inject the material slowly. If you accidentally enter the bladder or intestines withdraw and discard the needle and syringe.
Intravenous injections Intravenous injections are usually made into the dorsal tail vein. Warm the tail by immersing it in warm water or placing the animal under a heat lamp. The tail vein is easier to see in non-pigmented mice. A fine gauge needle should be used for this procedure. Signs of pain in the mouse. Pain relief For a detailed discussion of pain relief in mice refer to module 2. Generally opioids e. Drugs can be administered in water, in jello, as oral drops, by gavage or injected.
Drugs administered in water may be broken down in water, or insufficient quantities may be taken due to poor solubility in water or palatability problems. Anesthesia In general inhalant anesthetics are safer than injectable anesthetics. Halothane and isoflurane are the safest ones to use. Methoxyflurane is no longer available. Use of ether at Johns Hopkins University is subject to restrictions due to safety concerns. Ketamine and xylazine is a common injectable anesthetic combination.
Sodium pentobarbital can be used, but it has a narrow safety margin and is associated with a prolonged recovery period. For details on anesthetic techniques refer to the rodent surgery module. Euthanasia Euthanasia in mice is most often performed by carbon dioxide asphyxiation or overdose of an anesthetic agent. Use of cervical dislocation or decapitation in absence of deep anesthesia must be scientifically justified. All individuals performing euthanasia must be properly trained.
Individuals must also ensure that animals are dead before the carcass is disposed. Exsanguination or opening the thoracic cavity will ensure death. AVMA Panel on euthanasia report. Diseases of mice. Diseases of mice are usually handled as a herd colony health problem rather than on an individual animal basis.
The goal is to prevent introduction of a disease into a colony rather than to treat animals after disease outbreak. Disease prevention is practiced by institution of a disease surveillance sentinel program based on serological and microscopic diagnosis of problems in a representative sample of animals. Due to the widespread movement of animals all over the world with advent of genetic manipulation of animals, the possibility of introducing disease agents in a colony has markedly increased.
The expanded use of genetically modified and immunocompromised animals greatly exacerbates the problem. Furthermore the practice of transplanting tumor material into mice provides a portal where these agents can be introduced into animal, especially if the tumors are not screened for adventitious infectious agents. Some important mouse diseases are discussed below to draw attention to the need to adhere to practices recommended by the veterinary staff to avoid these diseases.
Pinworms Pinworms Syphacia and Aspicularis inhabit the intestine cecum, rectum, colon and have a direct lifecycle. The eggs are particularly resistant and survive for a long time in the environment. The disease is usually subclinical being marked in weanlings and immunocompromised animals.
Symptoms include poor body condition, rough hair coat, reduced growth rate and rectal prolapse. Infection with pinworms has a negative impact on gastrointestinal, growth, behavioral and immunology studies.
Affected animals are scruffy, pruritic itchy , loose hair and have scratch wounds, which can become infected with bacteria. There are changes in the immune responses of affected animals.
Mouse hepatitis virus This is a viral disease of mice that affects multiple organs. Weanlings are important in maintaining the disease in a colony. Outbreaks result in widespread deaths in neonates and occasionally weanlings, with or without diarrhea. Mouse hepatitis virus causes a wasting disease and high mortality in immunocompromised animals. This disease wreaks havoc in a colony, with disruption in research especially in oncology, transplantation, immunology, gastroenterology, metabolism and transgenic technology.
Ectromelia This viral disease is the worst nightmare in a mouse colony. There have been recent outbreaks at several facilities in United States associated with the injection of mouse sera or tissue culture material containing mouse sera into mice. The disease produces massive die off in adult mice and amputation of the limbs ectromelia in surviving animals.
Pox lesions mousepox appear on the skin. However, a brain can weigh slightly more or less depending on the mouse species. Average atomic mass of Cobalt : A single large chicken egg has a mass of about 57 grams on average with its shell on. By contrast, a jumbo graded chicken egg has a mass of 71 grams. The mass of a CD player will depend on the size of the CD player. On average, a CD player that only plays CDs has a mass of grams.
You divide grams by a thousand and get. The average is 20 grams according to this site. Average lab moue brain weight ranges between 0.
Approximately grams. A pet mouse can be weighed to assure health. Be sure it is receiving proper diet and exercise. The mass of one mole is the average atomic mass number of the chosen mass units, usually grams, in which the mole is expressed.
For sodium, the average atomic mass number is Log in. Units of Measure. Mice and Rats. Weight and Mass. Study now. See Answer. Best Answer. Study guides. Now typically lighter computer mice are going to be less reliable than heavier mice, however, due to the technology that apple builds their magic mice with, these will tend to have fewer issues than traditional computer mice that weigh the same as the magic mice.
Wired computer mice weigh more than wireless computer mice by 0. The average weight of a wireless computer mouse is 2. Computer mice with more buttons weigh 2. Computer mice that have more than two buttons weigh 5. Computer mice that have 2 buttons weigh 3. The more buttons a computer mouse has the more it will weigh. To help explain more I compared the weight of 6 of the best selling computer mice on the market.
Three of these had 2 buttons. The other three has multi[e buttons:. This being said, magic mice are still the clear winners weighing less due to the way they are designed. There is no correlation between the price of a computer mouse and how much it weighs. Instead, the weight of a computer mouse is determined by the function of the mouse, with vertical computer mice and trackball mice weighing the most. Some of the most expensive computer mice on the market weigh both above and below the average of what a computer mouse should weigh.
The lowest a wired computer mouse tends to weigh is 2. The lowest a wireless computer mouse tends to weigh is 0. The average weight of a Bluetooth computer mouse is 3. The lowest a Bluetooth mouse tends to weigh is 0. The most traditional Bluetooth computer mouse weighs 2. The average weight of a trackball computer mouse is 6.
0コメント