The Lost Mouse
The lost mouse, Mus erravicus, is a little-known mammal closely related to the common house mouse, Mus musculus. However, unlike his cousin, the lost mouse does not live in houses, but in backpacks. Indeed, the lost mouse got its name because of its habit of following humans when they travel, and, when spotted by them, looking “lost”.
At first glance, there is little difference between the lost mouse and other species of its genus. A more in-depth analysis of its morphological characteristics, however, will reveal that there are a few key aspects in which the lost mouse differs from other species of mice.
Its eyes, for instance, are slightly bigger and rounder than those of its relatives. The same can be said for its face. This, combined with the fact that, when discovered by humans, it does not flee, but rather looks up to its would-be captor, make it look extremely cute. This cuteness has evolved through the course of centuries, and attained such perfection that even the most ruthless of men would be smitten, giving it a bit of cheese or some crumbs of bread, instead of stomping it into oblivion.
In addition, mitochondrial analysis has shown that the lost mice specialize in long, sustained effort, allowing it to keep pace with a contingent of marching soldiers, or a pair of hikers.
Thus, the lost mouse follows its host, sometimes hiding in their luggage, and lives off of whatever leftovers they leave around, if they do not feed it outright.
In the past, the lost mouse was a symbol for travelers around the world. Even in ancient times, this peculiar rodent had a special place in some cultures. The maawi tribe of southern Zimbabwe would, when a young women or man came of age, gift them with a lost mouse, and send the on an initiation journey to complete their coming of age ceremony. The mouse was supposed to provide guidance and good fortune.
In Europe, journeyman apprentices would usually be accompanied by a lost mouse when they set out to complete their apprenticeship. In the late fifteen-hundreds, the species had become extremely common, and each new journey, even if it was only to the next village, had to be done with a lost mouse in tow.
In recent years, however, the custom of the lost mouse has been, well, lost. Most people today are not able to tell the difference between Mus erravicus and Mus musculus, and few are those who still see them as anything more than a pest.
The world population of lost mice has fallen to a few thousand individuals in the most recent estimates, a long way from their heyday, when the lost mouse was one of the most prolific members of its order. One of the reasons for this is that lost mice need to be removed at least 23.4 km (~15 miles) for it to be able to procreate, a feat which they can seldom achieve without any human help. Any less, and its sexual organs will not develop. It is believed that this mechanism is supposed to prevent inbreeding, since a lost mouse will not travel any further once it has given birth. Indeed, unlike other rodents, lost mice usually only have one litter. Due to the exhaustion from their travels and giving birth, they seldom survive for long once their offspring has reached independence.