habitat_narrative
Terrestrial
Very little is known about this rare species in the wild. The colloquial and scientific names refer to its pure white tail. Typically somewhat hamster-like in appearance, this stocky grey-coloured rat has a very short tail (about 35–40% of its head and body length) covered in dense short white hairs from which it derives its name. It is terrestrial and nocturnal and has several unusual physiological features: Their stomachs are adapted, via a complex microfauna and ruminant-like digestive system, to digest a wide range of plant foods that contain chemical defences and are thus not eaten by other species (Perrin and Maddock 1983, Downs and Perrin 1995), but there are no available data on preferred plant species from wild populations. It has a high metabolic rate well adapted to the Highveld winter (Monadjem et al. 2015), during which it reduces its activity and foraging times. However, there is no evidence suggesting that White-tailed Rats enter torpor (Perrin 2013). There remains no information about social and reproductive behaviour in the wild, and most data come from captive individuals which breed easily. Litter sizes vary between one and six and it is suspected that breeding takes place year round. They construct high-sided, cup-shaped nests which “look like Elizabethan neck ruffs” (Skinner and Chimimba 2005: 191), which is probably why the generic name is derived from the Greek mystron (meaning “spoon”) and mys (meaning “mouse”).The habitat requirements and ecology of White-tailed Rats merits further research. They are often associated with calcrete soils within grasslands. They are never found on soft, sandy substrate, rocks, wetlands or river banks. Furthermore, records from the Free State Province and Borakalalo Nature Reserve, North-West Province show that they can occur in disturbed areas (heavily grazed, D. MacFadyen pers. obs.) and in sparse grasslands (Kuyler 2000, Kaiser 2006, Avenant and Cavallini 2007, Avenant and Schulze 2012, Morwe 2013); for example, on shallow limestone substrate (Kuyler 2000, Morwe 2013, N.L. Avenant unpubl. data). Similarly, Vermeulen (2005) surveyed the Blaauwberg Conservation Area (BCA), Western Cape Province and found they had a preference for Dune Thicket on sloped clay soils, which disproves Friedmann and Daly's (2004) assertion that they require sandy soils. In Mpumalanga, they were recorded from areas of dense grass, as well as rocky areas with grass (Rautenbach 1978). In Lesotho and KZN, they are found along dolerite ridges, rocky slopes, basalt koppies (Lynch 1994, Taylor 1998). In the Maclear district of the Eastern Cape Province, it was found in habitats with crests and ridges and trapped on bare patches with sparse vegetation (Armstrong and van Hensbergen 1996a). They may have a preference for the Carletonville Dolomite Grasslands in North-West Province as is suggested by the museum records (Power 2014). On the Bokkeveld Plateau near Nieuwoudtville, Northern Cape, it was trapped in Dolerite Plains vegetation (O’Farrell et al. 2008). They do not occur in transformed habitat (croplands, fallow fields, or old fields). However, as they select microhabitats, such as slopes and ridges, small numbers may survive in non-arable patches within an agricultural matrix.
A controlled and replicated study analysing the effects of fire on the species in the BCA showed that about half the individuals trapped occurred in unburnt versus burnt habitats (60% in unburnt) whereas > 90% of other small mammals were recorded in unburnt areas (Specker 2006). This may indicate that the species is fire-adapted and Specker (2006) suggests that fire may trigger breeding. However, the study also suggests that unburnt areas are utilised in tandem with burnt areas and are perhaps needed as refuges from predation. Thus, a patch mosaic burning regimen, rather than a block-burn, may create the most desirable micro-habitat for this species (but see Parr and Andersen 2006). The species may require phase diversity, as observations suggest it exists in transitory habitat post-fire: they appear to enter grassland habitat about six months after a patch has burned and exit as the vegetation recovers (Kuyler 2000, Kaiser 2006, Avenant and Schulze 2012). Thus, the species follows plant succession closely, making disturbance important.
As they are nocturnal, they are often preyed on by Barn Owls (Tyto alba) as documented in studies analysing owl pellets (Avenant 2005, Avery et al. 2005). They live in burrows or crevices (de Graaf 1981, Armstrong and van Hensbergen 1996b), and can also swim (Hickman and Machiné 1986).
Ecosystem and cultural services: They have been recorded as a forage species for owls (Dean 1978; Avery et al. 2002, 2003, 2005; Avery and Avery 2011). Previously they were considered susceptible to plague which occurs sporadically in free-living populations but the National Institute for Communicable Diseases (2005) did not list them as plague-carrier.
