The riverine rabbit
is one of the world's rarest mammals and is endemic to the dense riverine
scrub along the seasonal rivers of the central Karoo of South Africa.
It is rated as Critically Endangered by the IUCN. Distinguishing marks
include a distinctive white ring around each eye and a black stripe
running from the corner of its mouth over its cheek. Weighing up to
1.9 kg (4.2 lb) its diet mainly consists of flowers and leaves; grasses
are included in the wet season. Riverine rabbits are nocturnal and solitary,
with a polygamous mating system and an unusually low breeding rate for
a rabbit.
It was seen several
times between 1902 and 1948, but it was then not seen again until
1979. Surveys in 1989 suggested that it survived only in the dense,
discontinuous vegetation in the districts of Victoria West, Beaufort
West and Frazerburg, an area of approximately 86 sq km (33 sq mi).
As of 2001, it was thought to occur in river catchments in the semi-arid
south central Karoo between Beaufort West and Williston, and Sutherland
and Victoria West. All its habitat is on private farmland!
Conservation
Status:
Conversion
of habitat for agriculture has been the major threat to the riverine
rabbit. Upwards of 60% of the original riparian vegetation where it
is found has been converted to cultivation. While the extent of this
habitat loss is significant it is currently static. Other threats
include: habitat loss due to firewood collecting and heavy grazing
pressure by sheep, traditional hunting with dogs, predation from uncontrolled
dogs roaming in the veldt, mortality due to traps such as the serrated
steel-jawed gin trap, and construction of dams which dry up the rivers.
Conservation
efforts by the Wildlife Society of Southern Africa and the South African
Nature Foundation (Now WWF SA), in concert with research activities,
have done much to draw attention to its plight. A number of governmental
and non-governmental organisations have joined together in the Riverine
Rabbit Conservation Project to carry out important conservation work.
A riverine rabbit
awareness program among the farmers of the central Karoo has been
instituted. Since the rabbit is found only on privately owned farms,
its survival depends on the willingness of landowners to adopt farming
methods to reduce over-grazing and other harmful practices in the
sensitive riverine habitat. Some Karoo farmers have declared their
farms Natural Heritage Sites to protect the riverine habitat and rabbit.
Population
Estimates:
1989: It was estimated that the remaining habitat potentially could
support 1435 rabbits but that the actual surviving population probably
was much smaller..
1995: Fewer than 1000.
1996: Probably well below 1000 animals.
How you can help:
Little Emily helping the riverine rabbits!
Emily van der Merwe (9), a grade 3 pupil of De Kuilen Primary in
Kuils River, is a great inspiration to all of us. Emily's parents
own a farm in the Northen Cape – the region also endemic
to the riverine rabbit. With riverine rabbits being on the verge
of extinction, Emily's passion for conservation gave her the inspiration
to have a fundraising event to help save the riverine rabbit.
An extract from Emily's letter:
"
My naam is Emily van der Merwe. Ek is 'n Gr 3 leerder van Laerskool
De Kuilen, Kuilsrivier. Ek hou baie van diere, en ek wil graag eendag
'n natuurbewaarder word. Ek het 'n fondsinsameling gehou omdat ek
dink dat te veel diere van Suid-Afrika, en ook reg oor die wêreld,
besig is om uit te sterf. Daarom moet ons begin help, en ook ons
deel doen daar om die wêreld 'n beter plek te maak. Ek het
gekies om die fondsinsameling vir die oewer koenyn te hou, omdat
ons 'n plaas het in die Noord Kaap, naby die omgewing waar die oewer
konyn voorkom."
Donate money
to the: "I
am 4 Earth" Riverrine Rabbit Fund
IUCN Categories:
1960's: -
1970's: -
1980's: Endangered
1994: Endangered
1996: Endangered; (Criteria: B1+2c)
2000: Endangered; (Criteria: B1+2c)
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Data on Biology and Ecology <-------------------------------------------------------
Name:
Riverine Rabbit
(Other Names:
Boshaas, Bushman Rabbit or Hare, Deelfontein Hare, Doekvoetjie, Pondhaas,
River Hare, Vleihaas)
Scientific Name:
Bunolagus monticularis
Size:
The riverine rabbit weighs 1.4 - 1.9 kg (3.1 - 4.2 lb).
Habitat:
The riverine rabbit lives only in dense riverine scrub in the alluvial
floodplains of the seasonal rivers in the central Karoo Desert. It
is restricted to riverine scrub of 0.5 - 1 m (1.6 - 3.2') in height
and to areas with soil types that allow stable burrows to be constructed.
(Avery 1988, Stuart & Stuart 1996)
Distribution:
As of 2001, it was thought to occur in river catchments in the semi-arid
south central Karoo between Beaufort West and Williston, and Sutherland
and Victoria West. It is found only on private farmland in riverine
vegetation along seasonal river courses. (Ahlmann 2001, Cape Nature
Conservation) > Distribution Map <
Gestation Period:
35 - 36 days (Stuart & Stuart 1996).
Birth Season:
Births occur during August through May.
Birth Rate:
One, rarely two per year.
Early Development:
A newborn riverine rabbit is altricial and is reared in a fur- and
grass-lined burrow. (altricial - refers to young mammals (e.g. rats,
mice, cats, dogs) that are helpless at birth; their eyes and ears
are sealed, and they cannot walk, maintain their body temperature,
or excrete without assistance)
Diet:
The riverine rabbit is predominantly a browser, eating flowers and
leaves from shrubs. Grasses are included in the diet when these are
available in the wet season.
The riverine rabbit
produces two types of droppings. At night, when the rabbit is active,
hard pellets are deposited. During the day, droppings are soft and
are reingested by the rabbit. In this way the riverine rabbit obtains
vitamin B, produced by bacteria in its hind gut, and minerals such
as calcium and phosphorus are recycled. (Collins 2001)
Behavior:
The riverine rabbit is nocturnal, feeding at night and resting during
the day in forms, which it scrapes out under a bush. It
is the only African rabbit where the female prepares an underground
burrow for her young. This nest is lined with grass and fur. (Nowak
1999)
Social Organization:
The riverine rabbit is solitary with a polygamous mating system. Males
and females each maintain home ranges which are exclusive with regard
to members of their own sex, with a male's home range overlapping
with the home ranges of several females.
Density/Range:
Density: Two censuses conducted in sections of the typical habitat
have yielded densities of 6.4 and 16.6 individuals/sq km (16.6 and
43.0 individuals/sq mi).
Home range:
The female home range = 12.9 hectares (32 acres) +/- 43%. The male
home range = 20.9 hectares (52 acres) +/-14%.
Minimum Viable
Population:
Minimum Viable Population Density: 6.4 individuals/sq km