Bunolagus monticularis (Riverine rabbit)
Deelfontein hare, river hare, bushman hare,
bushman rabbit [English]; rivierkonyn, vleihaas,
doekvoetjie, boshaas, pondhaas [Afrikaans]; Buschhase [German]; lièvre
des buissons [French]
Life
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Sarcopterygii (lobe-finned fish) > Stegocephalia
(terrestrial vertebrates) > Reptiliomorpha > Amniota >
Synapsida (mammal-like reptiles) > Therapsida > Theriodontia
> Cynodontia > Mammalia (mammals)
> Placentalia (placental mammals) >
Euarchontaglires > Glires > Lagomorpha (rabbits, hares and
pikas) > Family: Leporidae (rabbits, hares)
Identification
The Riverine rabbit has a typical rabbit shape but the body is more
elongated and the ears are longer and more hare-like. Distinguishing
facial marks include a distinctive white eye ring around each eye
and a black brown stripe along the sides of the lower jaw. The tail
is uniformly brown and resembles a “pom-pom”. The coat colour is
variable but is a reddish-brown shade grizzled with black, the underparts are a drab gray.
Size
Body length 52 cm; weight range 1.4 -1.9 kg.
Distribution and habitat
The Riverine Rabbit is endemic to the central
Karoo Desert of South Africa’s Cape Province (Northern and Western
Cape). Found in river catchments in the south Central Karoo
between Beaufort West and Williston, and Sutherland and Victoria West. It is a habitat specialist occupying a very restricted and
specialized riverine shrubland niche. The dense and diverse vegetation provides shelter
from heat and predators and a balanced diet. The soft and deep silt soils are of
critical importance to the species as it uses these soils for burrowing and
constructing breeding dens. Its range has halved due to habitat destruction as a
consequence of agricultural development.
General behaviour
Solitary and nocturnal, feeding at
night and resting during the day in shallow depressions (forms) that are scraped
out under Karoo shrubs.
Food
Predominantly a browser it eats the flowers and leaves of
Karoo shrubs. It grazes on new grass shoots during the wet season.
Reproduction
It is the only indigenous burrowing rabbit in Africa and
depends on the soft alluvial soils in the river floodplains to construct stable
breeding stops (burrows). The nest is lined with grass and belly fur from the
mother. When the young occupy the burrow the entrance is plugged with soil and
twigs to camouflage it from predators. With the erratic rainfall regime of the Karoo the condition of vegetation is most likely to play an important role in
the reproduction of the Riverine Rabbit. One or two helpless young (“kittens”)
are born during August through May after a 35-36 day long gestation period. They are blind, hairless and reared in a
lined burrow. Population growth is very slow as a female only produces an
average of 4 young in her lifetime of two to three years.
Life span
2 – 3 years.
History
The Riverine rabbit was first discovered in 1901 by a
British trooper at Deelfontein in the Karoo. Two specimen were sent to the
British Museum of Natural History where Oldfield Thomas, a researcher of the
museum, described them as being "of an entirely different type to anything
hitherto known, either from South Africa or from elsewhere“. In 1978 during a
research project by the Mammal Research Institute of the University of Pretoria
on southern African hares and rabbits - further rabbits were seen near Victoria
West. Genetic studies confirmed the fact that the Riverine Rabbit is a rabbit
and not a hare species. They are not closely related to other Southern African
hare and rabbit species. It’s closest living relatives includes the Amami Rabbit
from Japan, the Hispid Hare from India and the domestic rabbit (Oryctolagus
cuniculus) originally only from Europe.
Names
It is known by several common names:
-
Boshaas and vleihaas, these names arose from its
occurrence in the relatively moist and dense habitat.
-
"Doekvoetjie", refers to the broad hind paws which are
furred underfoot.
-
"Pondhaas", during the 1940s the curator of the
Kaffrarian Museum offered a pound for each riverine rabbit brought to him.
-
Bushman Rabbit or Hare, Deelfontein Hare.
Conservation
Threats:
The riverine rabbit is one of Southern Africa’s most
endangered mammals. Its ENDANGERED status was first recognised in 1981. During
2002 its conservation status upgraded to CRITICALLY ENDANGERED. With an
estimated 250 or less mature individuals in the wild today (with less than 1500
in total) the species is at an extremely high risk of extinction. The following
factors have contributed to population reduction.
-
The most serious threat to the survival of the riverine
rabbit is the fragmentation and loss of its unique habitat type. The
destruction and modification of the Karoo’s unique riverine habitats due to
overgrazing and other agricultural practices has had a significant impact on
the rabbit’s population over the past century. Fertile riverine soil is
preferred for cultivation. Upwards of 65% of the original riparian
vegetation has been lost due to cultivation.
-
Soil erosion causes more habitat loss.
-
Overgrazing damages the vegetation and leads to the
loss of important food sources.
-
Wood collection and bush clearing removes plant cover
exposing the rabbits to predators and heat.
-
Hunting with snares, gin traps and dogs also threatens
their survival. Traditional hunting by farm labour staff is still very
widely practised and rabbits and hares might still be hunted throughout the
Karoo region to provide a varied menu.
-
Dams, weirs and other constructions transform the
riverbanks and create barriers to natural movement, isolating populations.
Conservation strategy
The Riverine rabbit acts as an indicator species for these
river zones as its extinction in many areas of its former natural distribution
range indicates the degradation, fragmentation and loss of riverine vegetation.
It is also a Karoo flagship species and all efforts to conserve the Riverine
rabbit will be beneficial to other plants and animals in this ecoregion.
The Riverine rabbit can only be protected effectively if
its distribution is accurately known. Intensive habitat evaluation and mapping
exercises in the Western and Northern Cape supply necessary data to determine
the current distribution area of the rabbit. Although valuable research has been
carried out, still little is known about the biology and ecology of the Riverine
rabbit. Therefore research on the species and its habitat is providing crucial
information on which decisions will be based for the species conservation. It
has also been crucial to involve local people and farmers in order to obtain all
essential data, and to engage farmers and local communities in activities to
preserve the species and the precious remaining habitat. Besides establishing
and implementing effective environmental education and awareness programmes,
efforts to protect the Riverine rabbit are based on the formation of
conservancies whereby groups of private landowners along river courses agree to
prescribed conservation strategies.
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