Rodent Breeds of Altera
An archive of the various rodent species that are native to Altera
Altera, like most nations across the region, is home to a variety of species of rodent. Whilst more common
species of mice and rats share their genetic ancestry with other species across the region, Altera is home to several
unique types of rodent found only in a handful of places. Different types of rodent are found in the various biomes and
habitats throughout the nation; some domesticated and kept as pets - others regarded as pests.
Photo of a Common Mouse, commonly found
in both rural and urban environments
Country of Origin
The Common Altern Mouse, often also known as the Alteran Mouse or House Mouse, is a small mammal found within Alteran; though large colonies of the rodent are found throughout the region. The Alteran Mouse shared many common genetic traits with mice from across the Western Isles - leading many to believe either Altera was home to some of the earliest breeds of mice - or mice imported into Altera over the millennia have lead to eventual shared genetic structure. Characteristically, the Alteran Mouse is known for having a pointed snout, large rounded ears, and a long and hairy tail. It is one of the most abundant species of rodent in Altera and is thought to be the most populous. Although a wild animal, the Alteran Mouse has benefited significantly from associating with human habitation to the point that truly wild populations are significantly less common than the semi-tame populations near human activity.
The Alteran Mouse has been domesticated as the pet or fancy mouse, and as the laboratory mouse, which is one of the most important model organisms in biology and medicine. Until the early 2010s, many medical experiments involving the investigation of cures, genetics and medical advancements involved the Alteran Mouse; until animal experimentation was banned. Regardless of the dark history of experimentation using the Alteran Mouse, much of the scientific community herald the mouse as a keystone in the progression of medical advancement. In 2014 a statue commemorating the thousands of mice used, honouring their deaths and the advancements made as a consequence, was unveiled in Council of Education head office in Greyhelm, Altera.
Ancestry and Characteristics
Alteran mice have an adult body length (nose to base of tail) of between 7 to 10 centimetres, with a tail length of 5 to 10 cm - whilst typically weighting in the range of 40 to 45 g. In the wild they vary in color from grey and light brown to black, but domesticated variants of mice and laboratory mice are produced in many colors ranging from white to champagne to black. They have short hair and some, but not all, sub-species have a light belly. The ears and tail have little hair. The hind feet are short compared to other similar species, only 15 to 19 mm long; the normal gait is a run with a stride of about 4.5 cm, though they can jump vertically up to 45 cm. The vocal patterns of the Alteran mouse is a high-pitched squeak. Alteran mice thrive under a variety of conditions; they are found in and around homes and commercial structures, as well as in open fields and agricultural lands.
The tail, which is used for balance, has only a thin covering of hair as it is the main peripheral organ of heat loss in thermoregulation along with—to a lesser extent—the hairless parts of the paws and ears. Blood flow to the tail can be precisely controlled in response to changes in ambient temperature using a system of arteriovenous anastomoses to increase the temperature of the skin on the tail by as much as 10 °C to lose body heat. Tail length varies according to the environmental temperature of the mouse during postnatal development, so mice living in colder regions tend to have shorter tails. The tail is also used for balance when the mouse is climbing or running, or as a base when the animal stands on its hind legs (a behaviour known as tripoding), and to convey information about the dominance status of an individual in encounters with other mice.
In addition to the regular pea-sized thymus organ in the chest, Alteran mice have a second functional pinhead-sized thymus organ in the neck next to the trachea.
Ecology and Behaviour
Alteran mice usually run, walk, or stand on all fours, but when eating, fighting, or orienting themselves, they rear up on their hind legs with additional support from the tail – a behavior known as "tripoding". Mice are good jumpers, climbers, and swimmers, and are generally considered to be thigmotactic, i.e. usually attempt to maintain contact with vertical surfaces.
Mice are mostly crepuscular or nocturnal; they are averse to bright lights. The average sleep time of a captive house mouse is reported to be 12.5 hours per day. They live in a wide variety of hidden places near food sources, and construct nests from various soft materials. Mice are territorial, and one dominant male usually lives together with several females and young. Dominant males respect each other's territories and normally enter another's territory only if it is vacant. If two or more males are housed together in a cage, they often become aggressive unless they have been raised together from birth.
Alteran mice primarily feed on plant matter, but are omnivorous. They eat their own faeces to acquire nutrients produced by bacteria in their intestines. Alteran mice, like most other rodents, do not vomit.
The social behavior of the Alteran mouse is not rigidly fixed into species-specific patterns but is instead adaptable to the environmental conditions, such as the availability of food and space. This adaptability allows house mice to inhabit diverse areas ranging from sandy dunes to apartment buildings.
House mice have two forms of social behaviour, the expression of which depends on the environmental context. House mice in buildings and other urbanized areas with close proximity to humans are known as commensal. Commensal mice populations often have an excessive food source resulting in high population densities and small home ranges. This causes a switch from territorial behaviour to a hierarchy of individuals. When populations have an excess of food, there is less female-female aggression, which usually occurs to gain access to food or to prevent infanticide. Male-male aggression occurs in commensal populations, mainly to defend female mates and protect a small territory. The high level of male-male aggression, with a low female-female aggression level is common in polygamous populations. The social unit of commensal house mouse populations generally consists of one male and two or more females, usually related. These groups breed cooperatively, with the females communally nursing. This cooperative breeding and rearing by related females helps increase reproductive success. When no related females are present, breeding groups can form from non-related females.
Photo of a Red Brush squirrel in its
commonly seen summer red coat
Country of Origin
The Red Brush squirrel is found in both coniferous forest and temperate broadleaf woodlands in numerous regions across the Western Isles; though each colony has unique and distinct features. In Altera, Red Brush squirrels tend to have a mixed red and grey fur coat; rarely having a full, thick red coat. Red brush squirrels feast on hazelnuts by cracking the shell in half. Squirrels make a rough nest, called a ‘drey’, of twigs, leaves and strips of bark in the fork of a branch, high in the tree canopy.
Red brush squirrels rely on trees for food, with their diet mainly made up of seeds and nuts. Pine seeds are a particular favourite, but they will also take hazelnuts, and the seeds of larch and spruce. Also eaten are fruit, tree shoots, bark, lichen and fungi. Young birds and eggs may be taken, but this is rare. In autumn, squirrels will bury seeds and nuts, ready to be eaten in winter when food is scarce.
Before mating, males will follow females in prolonged chases through the trees and females will often mate with more than one partner. The young are born in a nest known as a drey. Dreys are located high up in trees and made from twigs and lined with moss, leaves and other soft materials. Up to six young are normally born in spring and they will begin foraging for their own food after around 10 weeks.
Ancestry and Characteristics
The red brush squirrel has a typical head-and-body length of 19 to 23 cm, a tail length of 15 to 20 cm, and a mass of 250 to 340 g. Males and females are the same size. The long tail helps the squirrel to balance and steer when jumping from tree to tree and running along branches and may keep the animal warm during sleep.
The red squirrel, like most tree squirrels, has sharp curved claws to help it to climb and descend broad tree trunks, thin branches, and even house walls. Its strong hind legs let it leap gaps between trees. The red squirrel also can swim.
The coat of the red squirrel varies in colour with time of year and location. There are several coat colour morphs ranging from black to red. Red coats are most common in Altera; in other parts of the region different coat colours co-exist within populations, much like hair colour in some human populations. The underside of the squirrel is always white-cream in colour. The red squirrel sheds its coat twice a year, switching from a thinner summer coat to a thicker, darker winter coat with noticeably larger ear-tufts (a prominent distinguishing feature of this species) between August and November. A lighter, redder overall coat colour, along with the ear-tufts (in adults) and smaller size, distinguish itself from other squirrel species. The red colour is for camouflage when seen against the bark of pine trees.
No territories are claimed between the red squirrels, and the feeding areas of individuals overlap considerably. This lack of territorial instinct makes it vulnerable to other species of squirrels, who easily outcompete with red brush squirrels for food and nesting sites. Due to this vulnerability, red brush squirrels are a protected species - importing other species of squirrel is illegal.
Ecology and Behaviour
The red squirrel is found in both coniferous forest and temperate broadleaf woodlands. The squirrel makes a drey (nest) out of twigs in a branch-fork, forming a domed structure about 25 to 30 cm in diameter. This is lined with moss, leaves, grass and bark. Tree hollows and woodpecker holes are also used. The red squirrel is a solitary animal and is shy and reluctant to share food with others. However, outside the breeding season and particularly in winter, several red squirrels may share a drey to keep warm. Social organization is based on dominance hierarchies within and between sexes; although males are not necessarily dominant to females, the dominant animals tend to be larger and older than subordinate animals, and dominant males tend to have larger home ranges than subordinate males or females.
The red squirrel eats mostly the seeds of trees, neatly stripping conifer cones to get at the seeds within, fungi, nuts (especially hazelnuts but also beech and chestnuts), berries and young shoots. More rarely, red squirrels may also eat bird eggs or nestlings. A study shows that out of 600 stomach contents of red squirrels examined, only 4 contained remnants of birds or eggs. Thus, red squirrels may occasionally exhibit opportunistic omnivore habits, similarly to other rodents. Excess food is put into caches, either buried or in nooks or holes in trees, and eaten when food is scarce. Although the red squirrel remembers where it created caches at a better-than-chance level, its spatial memory is substantially less accurate and durable than that of grey squirrels; it therefore will often have to search for them when in need, and many caches are never found again.
Between 60% and 80% of its active period may be spent foraging and feeding. The active period for the red squirrel is in the morning and in the late afternoon and evening. It often rests in its nest in the middle of the day, avoiding the heat and the high visibility to birds of prey that are dangers during these hours. During the winter, this mid-day rest is often much briefer, or absent entirely, although harsh weather may cause the animal to stay in its nest for days at a time.
Merito non pareret. | By merit, not birth.
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