Mitchell's Hopping Mouse
Encyclopedia
Mitchell's Hopping Mouse, Notomys mitchellii, is the largest extant member of the genus Notomys, weighing between 40 gram. N. mitchellii is a bipedal rodent
with large back legs, similar to a jerboa
or kangaroo rat
. The species occurs throughout much of semi-arid Southern Australia
, and appears to be particularly common on the Eyre Peninsula
, South Australia. Typical habitat for N. mitchellii appears to be mallee
shrublands on sandy dune systems. The species is currently considered to be unthreatened, but its range has been reduced through habitat disturbance and destruction associated with European settlement in Australia.
Individuals are a sandy grey colour, with white chest hairs and a paler underbelly. The tail of the species is long and has the characteristic hopping mouse brush at the tip. This tail morphology is thought to aid balance when travelling at speed. Being nocturnal, Notomys mitchellii shelters during the day in ‘typical’ hopping mouse burrows; a small number of interconnected, vertical shafts, burrowing deep into the dune. Up to eight animals, different ages and sex, have been found in a single burrow.
N. mitchellii is known to have a lifespan of up to five years in the laboratory and this is thought to be a strategy evolved to combat the breeding-constraints of lengthy periods of drought. It has also been found that this species is less able to cope with water deprivation than other species of the genus. Notomys mitchellii produces concentrated urine to conserve water, but in a different way to more arid-dwelling rodents. The diet of N. mitchellii is also thought to consist of more roots and green matter than that of other species of the genus: animals captured in drought conditions had stomach contents consisting of some 85% roots, 11% green leaf and 4% seed.
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
with large back legs, similar to a jerboa
Jerboa
The jerboa form the bulk of the membership of the family Dipodidae. Jerboas are hopping desert rodents found throughout Asia and Northern Africa. They tend to be found in hot deserts....
or kangaroo rat
Kangaroo rat
Kangaroo rats, genus Dipodomys, are small rodents native to North America. The common name derives from their bipedal form: as they hop in a manner similar to the much larger kangaroo, although they are not related...
. The species occurs throughout much of semi-arid Southern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, and appears to be particularly common on the Eyre Peninsula
Eyre Peninsula
Eyre Peninsula is a triangular peninsula in South Australia. It is bounded on the east by Spencer Gulf, the west by the Great Australian Bight, and the north by the Gawler Ranges. It is named after explorer Edward John Eyre who explored some of it in 1839-1841. The coastline was first explored by...
, South Australia. Typical habitat for N. mitchellii appears to be mallee
Mallee Woodlands and Shrublands
Mallee Woodlands and Shrublands is a Major Vegetation Group which occurs in semi-arid areas of southern Australia. The vegetation is dominated by mallee eucalypts which are rarely over 6 metres high...
shrublands on sandy dune systems. The species is currently considered to be unthreatened, but its range has been reduced through habitat disturbance and destruction associated with European settlement in Australia.
Individuals are a sandy grey colour, with white chest hairs and a paler underbelly. The tail of the species is long and has the characteristic hopping mouse brush at the tip. This tail morphology is thought to aid balance when travelling at speed. Being nocturnal, Notomys mitchellii shelters during the day in ‘typical’ hopping mouse burrows; a small number of interconnected, vertical shafts, burrowing deep into the dune. Up to eight animals, different ages and sex, have been found in a single burrow.
N. mitchellii is known to have a lifespan of up to five years in the laboratory and this is thought to be a strategy evolved to combat the breeding-constraints of lengthy periods of drought. It has also been found that this species is less able to cope with water deprivation than other species of the genus. Notomys mitchellii produces concentrated urine to conserve water, but in a different way to more arid-dwelling rodents. The diet of N. mitchellii is also thought to consist of more roots and green matter than that of other species of the genus: animals captured in drought conditions had stomach contents consisting of some 85% roots, 11% green leaf and 4% seed.
Phylogenetic Tree
On the phylogenetic tree is can be seen that the ancestor of the Mitchell’s hopping mouse diverged approximately 70million years ago. Mitchell’s hopping mouse is closely related to Dipodidae which is a northern hemisphere jumping rodents such as the jerboa. As their common ancestor diverged of an ancestor which evolved into creature which around the same time evolved again into families such as Pedetidae which consist of small hare like animals and Castoridae which are beavers.Analogous Structure
An analogous structure off the Mitchell’s hopping mouse is their hind legs like the hind legs of a quokka or even a kangaroo. This structure is strong and muscular therefore allowing them to achieve power driven jumping covering more distance. This structure serves a similar purpose in the quokka and kangaroo either moving or jumping quickly from on coming predators.Homologous Structure
An homologous structure the Mitchell’s hopping mouse is it’s long ears. As The Dipodidae family is closely related to the Muridae family as they diverged from the same common ancestor we can see the similarity of their ear structure which are seen to be very long. This can be used to hear their predators advancing towards allowing them to achieve a quick escape.Further reading
- Watts CHS, Aslin HJ. 1981. The Rodents of Australia. London: Angus & Robertson
- Baverstock PR. 1979. A Three Year Study of the Mammals and Lizards of Billiatt Conservation Park in the Murrat Mallee, South Australia. South Australian Naturalist 53:52-8
- Strahan R, ed. 1998. The Mammals of Australia. The National Photographic Index of Australian WildlifeNational Photographic Index of Australian WildlifeThe National Photographic Index of Australian Wildlife was founded as a project of the Australian Museum on 3 June 1969 to compile a comprehensive collection of photographs of Australian bird species. The founder, Donald Trounson, served as the project’s chief executive officer until 1981, when...
. Sydney, NSW: Reed New Holland