House Mouse Facts & Other Species of Mice

by AppleCheeks Wed 06 Apr 2016, 5:05 pm

The content on this page was first published on The Fun Mouse website and has been reposted with permission. Please do not reproduce in any way.

Environment

Housing Temperatures: Mice should be kept between 65°F and 80°F (18°C to 26°C) at all times. Temperatures exceeding this can cause chills, lethargic mice, illness, and even death.

Humidity: The humidity level should stay between 30% and 70%. Too high humidity can cause ringtail, higher ammonia levels, and illness while lower humidity can cause dryness of the skin.

Health Physiology & Anatomy

*Based on a 20g mouse.
*Data will vary based on age, size, weight, weight, individual, strain, environmental conditions, etc.

Blood pressure: 83-164 mm Hg (millimeters of mercury)

Heart rate: A healthy new born should have 286 +/- 56.8 bpm (beats per minute) and an adult should have 632 +/- 51.3 bpm.

Respiratory rate: ~163 per minute

Body temperature: 98.42°F

Teeth: Mice have 16 teeth. Unlike humans, mice do not loose baby teeth and grow adult teeth. Mice have one set of teeth their entire life that continuously grow. The top front teeth of the mouse (incisors) should slightly overlap in front of the bottom teeth. If the bottom incisors are in front of the top, this is called malocclusion. If the teeth butt up against each other, this is called simple malocclusion. Malocclusion can cause the teeth to break, wear oddly, cause severe damage to the mouth, and make a mouse unable to eat. It helps to give them something to chew on, but this will not likely fix the problem. Note that because their teeth grow their entire lives, mice should always have something to chew on, malocclusion or not. It is likely that a mouse with malocclusion will need vet attention, to trim the teeth down. Never attempt this on your own, as teeth can easily be pulled out accidentally. This can possibly result in death of the mouse because he/she can't eat.

Life cycle

Life span: 1-1/2 to 3 years, 2 years being the average. Wild mice live around 5 years in captivity, though only around 6 months in the wild due to predators and environmental factors.

Maturity: 4 - 8 weeks of age, varying from line to line and mouse to mouse. This is the time that males and females can become fertile. However, note that a female can die if she conceives that young. **see below**

Females estrus (heat) cycle: Every 4 to 5 days all year round until becoming pregnant. *Sometimes estrus will stop in all female colonies and pick up again roughly 3 days after a male is introduced (this is called the Whitten Effect). Sometimes females will also have odd cycles in the winter.

Ovulation: Some sources (from labs) claim 2-3 hours, some claim 12 hours.

Complete Physical Maturity: Mice are not done growing until they are between 3 and 5 months of age, depending on the line. Mice should NEVER be bred until they are at least 12 weeks age. If you don't know the line really well, wait until at least 12 weeks, if not longer. Breeding too young can cause a weak mother, weak babies, shorter life spans, and even death of mothers and babies.

Optimal Breeding Age: Unless the line is extremely well known, the best breeding age for a female mouse is between the ages of 3 months (though it's best to wait until 4 months) and 8 months. First litters should be done before the mouse is 6-7 months of age. These time frames can vary from line to line, but this is a general rule for safe breeding. It is of no health risk to the male or his offspring to breed him at any age as long as he is healthy. Keep in mind however, that a male might be fully fertile at 4 weeks or as late as 8 weeks.

Gestation: 19-24 days. The average is 20 days.

Postpartum Estrus: A female can come back into heat 14-28 hours after giving birth! This means that she can become pregnant after having her litter. Females should NEVER have back to back litters. It risks the health of the mother as well as the babies. It can even result in death of some or all of them (including the mother)!

Litter size: 1-24 pups. The average is between 9 and 12 pups.

Ears open: Ears can open as early as day 3, but some don't open until later.

Eyes open: Babies open their eyes around day 14, give or take a few days depending on the litter.

Weaning: 4 weeks of age. It is best not to take the babies from their mother until they are 4 weeks of age, to the day. Once the males are 4 weeks of age, they need to be taken away from the group to prevent unwanted breeding (to the mom and the sisters). Also note that males often need to be separated from each other at that time. Male mice, especially those from pet shop mice and lines that haven't been *thoroughly* tracked, will fight to the death. Even siblings will fight 99% of the time. Fighting usually happens without ANY notice what so ever and at night, when their caregiver(s) are not around to separate them. Fighting to the death is quick and usually completely unpredictable/unpreventable without separating them all at 4 weeks.

End of Fertility: Most mice are fertile any time after 4 weeks of age until death. NEVER assume that either sex is too old to produce offspring. As a mouse ages, it might take them longer to actually produce a litter (due to lower sperm count or irregular estrus cycles) or conception could happen in a matter of less than a second. Pregnancy in females can and will occur late in life, if given the chance, though it can be detrimental to the mother as well as the offspring (often resulting in death).

by AppleCheeks Wed 06 Apr 2016, 6:11 pm

Introduction

The Deer Mouse (Peromyscus maniculatus) and the White-Footed Mouse (Peromyscus leucopus) are very closely related to each other, yet they are both very distantly related to the House Mouse (Mus musculus). All three of these species are members of the Rodentia group, but from there the house mouse is classified much differently than deer mice and white-footed Mice. Deer mice and white-footed mice are of the family Cricetidae, subfamily Neotominae, and genus Peromyscus. The house mouse is of the family Muridae, subfamily Murinae, and Genus Mus. The chart below will help visualize how distantly related these 3 species are from each other.

The house mouse is what your pet Fancy Mice are. All fancy mice are the same species, regardless of color, markings, body type, coat type, etc. Feeder mice are also your standard fancy mice, they are just given a different descriptive name by pet shops. Neither deer mice, nor white-footed mice, can breed with house mice. While they look very similar, they are extremely different.

House Mouse Facts & Other Species of Mice Classi10

Field Mice are not mentioned because the term "field mouse" is a generic catch-all phrase for many various species of wild mice. The term "field mouse" may also signify a more specific species (often more than one), yet the species it indicates greatly varies depending on where in the world the term is being used. To add to the confusion, white-footed mice are often called deer mice, though this is inaccurate.

Deer Mouse - Peromyscus maniculatus

House Mouse Facts & Other Species of Mice Deermo10

Weight: 10g to 24g
Total Length: 119mm to 222mm
Tail length: 45mm to 105mm
Hind feet: 20mm[/center]

Deer mice are hairier than white-footed mice and house mice, especially around and on the ears. In addition to their hairy ears, deer mice often (though not always) have white hairs at the base of their ears resembling white tuffs, as seen in the illustration above. Deer mice have a white or very light beige belly and an agouti body which can range from gray to a rich red-brown. The shade of the deer mouse often varies based on location. Perhaps the most distinguishing visual attribute is their tail. Deer mice have a remarkably noticeable two-tone tail. The top of the tail is very dark, while the bottom of the tail lacks any pigment at all, as shown in the pictures above. This continues most of the length of the tail. Other species have two-tone tails, but not nearly as noticeable as deer mice. While their tail can vary in length, it is generally longer than that of the white-footed mouse and house mouse as well.

Deer mice prefer moist, cool forest environments and will be found in higher elevations a great deal more than white-footed mice and house mice.

White-Footed Mouse - Peromyscus leucopus

House Mouse Facts & Other Species of Mice 81543210

Source: Smithsonian Institution National Museum of Natural History (NMNH)
Credit: photo by Roger W Barbour

Weight: 15g to 25g
Total Length: 150mm to 205mm
Tail length: 65mm to 95mm
Hind feet: 22mm or more[/center]

White-Footed Mice have a white belly and an agouti body which can range from gray, pink-beige, to red in color. These mice have fur on the heels of their feet as well as larger soles and greater over all foot length than the other two species discussed on this page.

White-footed mice can vary greatly from deer mice. However, this may not always be the case. These two species can be exceedingly difficult to distinguish from one another based on appearance alone. They both vary in appearance depending on where they are located, which can cause them to look particularly similar.

House Mouse - Mus musculus

Keep in mind this is outlined for *wild* house mice, not domestic house mice which have been selectively bred for different sizes, shapes, colors, coats, etc than their wild counterparts. Domestic house mice will vary considerably.

Weight: 10g to 25g
Total Length: 75mm to 100mm
Tail length: 50mm to 100mm
Hind feet: 15mm to 19mm[/center]

The fur of the House Mouse is also agouti. The tan part of their coat can vary from light dun to a rich brown-red, similar to the coats of their domestic counterpart. Some house mice have a white belly while others have a light beige agouti belly which gradually darkens from their belly to their back. Their ears are significantly smaller and set further apart than deer mice and white-footed mice. House mice have a relatively naked and scaly tail in comparison to the other two species as well. House mice tend to smell worse and horde food less often than deer mice and white-footed mice. House mice also have smaller eyes, body length, and foot length than the other two species.