Bolam's mouse
Bolam's mouse is a species of nocturnal, burrowing rodent in the family Muridae that inhabits the semi arid and southern arid regions of Australia. It has a number of physiological and behavioural adaptations developed to cope with an extremely varied climate. These include the ability to survive by extracting water from seeds alone, the production of highly concentrated urine, low water content faeces and nocturnal activity.
Description
Bolam's mouse is the size of a house mouse although slimmer in appearance with larger eyes, feet and ears with a longer tail. It is also quieter than a house mouse when handled and lacks a musty odour. Other distinguishing features include the absence of notched upper incisors which are characteristic of the house mouse. The weight of males and females is between 9 and 16 grams. The body length is with a tail length of. The fur is a dull grey-brown that blends from white at the base to much darker at the tips. It is very similar in appearance to the sandy inland mouse, Pseudomys hermannsburgensis, but with a longer hindfoot, 4–6 hairs per tail scale and longer ears.Taxonomy
Bolam's mouse was first described by Troughton in 1932 as a subspecies of the sandy inland mouse, as Pseudomys hermannsburgensis bolami. It was reclassified as a separate species by Kitchener et al. in 1984 based on nucleic acid electrophoretic and morphometric characters.Distribution
It has a wide distribution that ranges from south west Western Australia through South Australia to south western New South Wales. The range of the species has declined in recent times with the species no longer found in the Sunset region of South Australia and Victoria. Fossil evidence shows that its range has also contracted in New South Wales where it formerly occupied much of the west of the state including Mutawintji National Park in the north west. The range of Bolam's mouse is generally south of that of the sandy inland mouse with very little overlap in distribution.Diet
Bolam's mouse is an omnivorous rodent that feeds on a mixture of seed, plant material, invertebrates and fungus. Due to the high variability of food resources available to P. bolami its diet is seasonally varied. Generally seeds particularly those of Maireana astrotricha occupy the majority of the diet when conditions are suitable for seed production. Plant material including leaves, floral material, stems and roots generally make up more than 30% of the diet. Invertebrates make up more than 10% of the diet and fungus makes up less than 1%.Life Cycle
Bolam's mouse has been recorded breeding in all seasons but typically breeds in spring and early summer to coincide with available food resources. It has also been observed to have an opportunistic breeding pattern that peaks with an elevenfold increase in numbers 12 months after a significant rainfall event to exploit additional food resources. Individuals are sexually mature when a body mass of is reached. Females can have 4–6 offspring. The estimated life span of Bolam's mouse is as low as two years.Habitat
It is found in a range of vegetation communities within the arid and semi-arid regions of Australia. These communities range from Mallee-spinifex, Mallee-Shrubland, Belah woodland, mixed open shrubland/woodland, chenopod shrubland plains and Acacia/Eucalyptus woodlands.They are found to inhabit areas that have loamy, clay, gravelly, sandy or calcareous soils where they are able to burrow. They also occupy vacant goanna, bettong and rabbit burrows and underneath fallen timber.