Golden moles are small insectivorous burrowing
mammals
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...
to
Sub-Saharan Africa. They comprise the family Chrysochloridae and as such they are
taxonomically
In biology, taxonomy () is the scientific study of naming, defining ( circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa (singular: taxon) and these groups are given ...
distinct from the
true moles, family
Talpidae
The family Talpidae () includes the moles (some of whom are called shrew moles and desmans) who are small insectivorous mammals of the order Eulipotyphla. Talpids are all digging animals to various degrees: moles are completely subterranean ...
, and other
mole
Mole (or Molé) may refer to:
Animals
* Mole (animal) or "true mole", mammals in the family Talpidae, found in Eurasia and North America
* Golden moles, southern African mammals in the family Chrysochloridae, similar to but unrelated to Talpida ...
-like families, all of which, to various degrees, they resemble as a result of
evolutionary convergence
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...
. There are 21 species. Some (e.g., ''Chrysochloris asiatica'', ''Amblysomus hottentotus'') are relatively common, whereas others (e.g., species of ''Chrysospalax'', ''Cryptochloris'', ''Neamblysomus'') are rare and endangered.
Characteristics and affinities
Like most burrowing mammals with similar habits, the Chrysochloridae have short legs with powerful digging claws, very dense fur that repels dirt and moisture, and toughened skin, particularly on the head. Their eyes are non-functional and covered with furred skin. The external ears are just tiny openings. In particular, golden moles bear a remarkable resemblance to the
marsupial mole
Marsupial moles, the Notoryctidae , are highly specialized marsupial mammals, known from two species found at the Australian interior.
* ''Notoryctes typhlops'' (southern marsupial mole, known as the ''itjaritjari'' by the Pitjantjatjara and Yan ...
s of
Australia, family
Notoryctidae
Notoryctidae is a family of mammals, allying several extant and fossil species of Australia.
The group appear to have diverged from other marsupials at an early stage and are highly specialised to foraging through loose sand; the unusual feature ...
, which they resemble so suggestively that at one time, the
marsupial
Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a ...
/
placental
Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguishe ...
divide notwithstanding, some argued that they were related. Considerations that influenced the debate might have included the view that the Chrysochloridae are very primitive placentals and the fact that they have many mole-like specializations similar to specializations in marsupial moles. The
rhinarium
The rhinarium (New Latin, "belonging to the nose"; plural: rhinaria) is the furless skin surface surrounding the external openings of the nostrils in many mammals. Commonly it is referred to as the tip of the ''snout'', and breeders of cats and ...
is a greatly enlarged, dry leathery pad that protects their nostrils while the animal digs. In this respect, too, they resemble the marsupial moles. Some authors claim their primary sense is of
touch
In physiology, the somatosensory system is the network of neural structures in the brain and body that produce the perception of touch ( haptic perception), as well as temperature ( thermoception), body position (proprioception), and pain. It ...
, and they are particularly sensitive to vibrations, which may indicate approaching danger.
Note below, however, the observations on the
malleus
The malleus, or hammer, is a hammer-shaped small bone or ossicle of the middle ear. It connects with the incus, and is attached to the inner surface of the eardrum. The word is Latin for 'hammer' or 'mallet'. It transmits the sound vibrations f ...
in the middle ear.
The species range in size from about to about . They have muscular shoulders and the forelimbs are radically adapted for digging; all the toes on the forefeet have been reduced, except for a large, pick-like third claw on the third toe. The fifth digit is absent and the first and fourth digits are vestigial. The adaptations of the hind feet are less dramatic: They retain all five toes and are webbed as an adaptation to efficient backward shovelling of soil loosened by the front claws.
At one time, the Chrysochloridae were regarded as
primitive. Supporting arguments of this included that they were thought to have originated in
Gondwana, that they had a low resting metabolic rate, and that they could switch off thermoregulation when inactive. Like the
tenrec
A tenrec is any species of mammal within the afrotherian family Tenrecidae endemic to Madagascar. Tenrecs are wildly diverse; as a result of convergent evolution some resemble hedgehogs, shrews, opossums, rats, and mice. They occupy aquatic, a ...
s, they possess a
cloaca, and males lack a
scrotum
The scrotum or scrotal sac is an anatomical male reproductive structure located at the base of the penis that consists of a suspended dual-chambered sac of skin and smooth muscle. It is present in most terrestrial male mammals. The scrotum co ...
. However, these points are no longer regarded as strongly suggestive of golden moles as undeveloped "reptilian mammals"; some are seen rather as adaptations to regional climatic conditions. Going into a torpor when resting or during cold weather enables them to conserve energy and reduce urgent requirements for food. Similarly, they have developed particularly efficient kidneys, and most species do not need to drink water at all; in fact, they tend to drown easily if they fall into water.
Habits and ecology
Chrysochloridae are subterranean, afrotherian mammals endemic to sub-Saharan Africa, and most of which are recorded from South Africa in particular. Other regions include
Lake Victoria, Western Cape,
and Namibia. They live in a variety of environments; forest, swamps, deserts, or mountainous terrain. However, ''
Chrysospalax
''Chrysospalax'' is a small genus of mammal in the family Chrysochloridae. The two members are endemic to South Africa. It contains the following species:
* Rough-haired golden mole (''Chrysospalax villosus'')
* Giant golden mole
The giant gol ...
'' species tend to forage above ground in leaf litter in forests or in meadows. ''
Eremitalpa
Grant's golden mole (''Eremitalpa granti''; colloquially also: ''dune shark'') is a golden mole species. It is the only member of the genus ''Eremitalpa''.
Attributes
Like all other golden moles, the build of these animals is similar to the mo ...
'' species such as Grant's golden mole live in the sandy
Namib desert
The Namib ( ; pt, Namibe) is a coastal desert in Southern Africa. The name is of Khoekhoegowab origin and means "vast place". According to the broadest definition, the Namib stretches for more than along the Atlantic coasts of Angola, Nami ...
, where they cannot form tunnels because the sand collapses. Instead during the day, when they must seek shelter, they "swim" through the loose sand, using their broad claws to paddle, and dive down some 50 cm to where it is bearably cool. There they enter a state of torpor, thus conserving energy.
[ Piper, Ross (2007), ''Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals'', Greenwood Press] At night they emerge to forage on the surface rather than wasting energy shifting sand. Their main prey are termites that live under isolated grass clumps, and they might travel for 6 kilometres a night in search of food. They seek promising clumps by listening for wind-rustled grass-root stresses and termites' head-banging alarm signals, neither of which can be heard easily above ground, so they stop periodically and dip their heads under the sand to listen.
Most other species construct both foraging superficial burrows and deeper permanent
burrows for residence. Residential burrows are relatively complex in form, and may penetrate as far as a metre below ground and include deep chambers for use for refuge, and other chambers as latrines. They push excavated soil up to the surface, as in mole-hills, or compact it into the tunnel walls.
They feed on small insects and earthworms or small vertebrates such as lizards or burrowing snakes. They depend on their sense of hearing to locate much of their prey, and the
cochlea
The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus. A core component of the cochlea is the Organ of Corti, the sensory or ...
s of a number of golden mole species have been found to be long and highly coiled, which may indicate a greater ecological dependence on low frequency auditory cues than we see in
Talpid moles.
Morphology
Golden Moles share a number of features, varying by species, seldom seen elsewhere among living mammals, including three forearm long-bones,
hyoid
The hyoid bone (lingual bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies between the base of the mandible and the third cervical vertebra. ...
-
mandible
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...
articulation, and a hypertrophied
malleus
The malleus, or hammer, is a hammer-shaped small bone or ossicle of the middle ear. It connects with the incus, and is attached to the inner surface of the eardrum. The word is Latin for 'hammer' or 'mallet'. It transmits the sound vibrations f ...
.
Some species have hypertrophied (enlarged) middle ear
ossicles, in particular the malleus. These animals have the largest malleus relative to body size of any animal. This morphology may be adapted for the detection of seismic signals.
In this respect there is some apparent convergent evolution to burrowing reptiles in the family
Amphisbaenidae
The Amphisbaenidae (common name: worm lizards) are a family of amphisbaenians, a group of limbless vertebrates.
Geographic range
Amphisbaenids occur in South America, some Caribbean islands, Europe, and sub-Saharan Africa.
Taxonomy
One deep- ...
.
Reproduction
Females give birth to one to three hairless young in a grass-lined nest within the burrow system. Breeding occurs throughout the year. The adults are solitary, and their burrowing territory may be aggressively defended from intruders, especially where resources are relatively scarce.
[
]
Status
Of the 21 species of golden mole, no fewer than 11 are threatened with extinction. The primary cause being human-induced habitat loss, additionally sand mining
Sand mining is the extraction of sand, mainly through an open pit (or sand pit) but sometimes mined from beaches and inland dunes or dredged from ocean and river beds. Sand is often used in manufacturing, for example as an abrasive or in conc ...
, poor agricultural practices, and predation by domestic cats and dogs are causes of population decline.
Classification
The taxonomy of the Chrysochloridae is undergoing a review in the light of new genetic information. They have traditionally been listed with the shrew
Shrews (family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to differ ...
s, hedgehog
A hedgehog is a spiny mammal of the subfamily Erinaceinae, in the eulipotyphlan family Erinaceidae. There are seventeen species of hedgehog in five genera found throughout parts of Europe, Asia, and Africa, and in New Zealand by introductio ...
s and a grab-bag of small, difficult-to-place creatures as part of the order Insectivora
The order Insectivora (from Latin ''insectum'' "insect" and ''vorare'' "to eat") is a now-abandoned biological grouping within the class of mammals. Some species have now been moved out, leaving the remaining ones in the order Eulipotyphla, wi ...
. Some authorities retain this classification, at least for the time being. Others group the golden moles with the tenrec
A tenrec is any species of mammal within the afrotherian family Tenrecidae endemic to Madagascar. Tenrecs are wildly diverse; as a result of convergent evolution some resemble hedgehogs, shrews, opossums, rats, and mice. They occupy aquatic, a ...
s in a new order, which is sometimes known as Tenrecomorpha
Tenrecomorpha is the suborder of otter shrews and tenrecs, a group of afrotherian mammals indigenous to equatorial Africa and Madagascar, respectively. The two families are thought to have split about 47–53 million years ago. Potamogalid ot ...
, while others call it Afrosoricida
The order Afrosoricida (a Latin-Greek compound name which means "looking like African shrews") contains the golden moles of Southern Africa, the otter shrews of equatorial Africa and the tenrecs of Madagascar. These three families of small mamm ...
and reserve Tenrecomorpha for the family Tenrecidae.
* ORDER AFROSORICIDA
The order Afrosoricida (a Latin-Greek compound name which means "looking like African shrews") contains the golden moles of Southern Africa, the otter shrews of equatorial Africa and the tenrecs of Madagascar. These three families of small mamm ...
** Suborder Tenrecomorpha
Tenrecomorpha is the suborder of otter shrews and tenrecs, a group of afrotherian mammals indigenous to equatorial Africa and Madagascar, respectively. The two families are thought to have split about 47–53 million years ago. Potamogalid ot ...
*** Family Tenrecidae: tenrecs, 34 species in 10 genera
** Suborder Chrysochloridea
*** Family Chrysochloridae
**** Subfamily Chrysochlorinae
***** Genus ''Carpitalpa
Arends'
golden mole (''Carpitalpa arendsi'') is a species of mammal in the family Chrysochloridae. It is found in Mozambique and Zimbabwe. Its natural habitats are temperate forests, subtropical or tropical dry, and moist montane forests, dry ...
''
****** Arends's golden mole
Arends'
golden mole (''Carpitalpa arendsi'') is a species of mammal in the family Chrysochloridae. It is found in Mozambique and Zimbabwe. Its natural habitats are temperate forests, subtropical or tropical dry, and moist montane forests, dry ...
(''Carpitalpa arendsi'')
***** Genus ''Chlorotalpa
''Chlorotalpa'' is a genus of mammal in the family Chrysochloridae. It contains the following species:
* Duthie's golden mole
Duthie's golden mole (''Chlorotalpa duthieae'') is a species of mammal in the family Chrysochloridae. It is endemi ...
''
****** Duthie's golden mole (''Chlorotalpa duthieae'')
****** Sclater's golden mole
Sclater's golden mole (''Chlorotalpa sclateri'') is a species of mammal in the family Chrysochloridae. It is found in Lesotho and South Africa. Its natural habitats are subtropical or tropical dry and high-altitude shrubland, Mediterranean-type s ...
(''Chlorotalpa sclateri'')
***** Genus ''Chrysochloris
''Chrysochloris'' is a genus of mammal in the family Chrysochloridae.
It contains the following species:
* Subgenus ''Chrysochloris''
**Cape golden mole
The Cape golden mole (''Chrysochloris asiatica'') is a small, insectivorous mammal of ...
''
****** Subgenus ''Chrysochloris''
******* Cape golden mole
The Cape golden mole (''Chrysochloris asiatica'') is a small, insectivorous mammal of the family Chrysochloridae, the golden mole
Golden moles are small insectivorous burrowing mammals endemic to Sub-Saharan Africa. They comprise the family ...
(''Chrysochloris asiatica'')
******* Visagie's golden mole (''Chrysochloris visagiei'')
****** Subgenus ''Kilimatalpa''
******* Stuhlmann's golden mole (''Chrysochloris stuhlmanni'')
***** Genus ''Chrysospalax
''Chrysospalax'' is a small genus of mammal in the family Chrysochloridae. The two members are endemic to South Africa. It contains the following species:
* Rough-haired golden mole (''Chrysospalax villosus'')
* Giant golden mole
The giant gol ...
''
****** Giant golden mole (''Chrysospalax trevelyani'')
****** Rough-haired golden mole (''Chrysospalax villosus'')
***** Genus '' Cryptochloris''
****** De Winton's golden mole (''Cryptochloris wintoni'')
****** Van Zyl's golden mole (''Cryptochloris zyli'')
***** Genus ''Eremitalpa
Grant's golden mole (''Eremitalpa granti''; colloquially also: ''dune shark'') is a golden mole species. It is the only member of the genus ''Eremitalpa''.
Attributes
Like all other golden moles, the build of these animals is similar to the mo ...
''
****** Grant's golden mole
Grant's golden mole (''Eremitalpa granti''; colloquially also: ''dune shark'') is a golden mole species. It is the only member of the genus ''Eremitalpa''.
Attributes
Like all other golden moles, the build of these animals is similar to the m ...
(''Eremitalpa granti'')
**** Subfamily Amblysominae
***** Genus ''Amblysomus
''Amblysomus'' (also narrow-headed golden mole or South African golden mole) is a genus of the golden mole family, Chrysochloridae, comprising five species of the small, insect-eating, burrowing mammals endemic to Southern Africa. All five spec ...
''
****** Fynbos golden mole
The fynbos golden mole (''Amblysomus corriae'') is a species of mammal in the golden mole family, Chrysochloridae. It is endemic to South Africa.
Its natural habitats are fynbos vegetation, temperate forests, shrubland, and grassland, subtropi ...
(''Amblysomus corriae'')
****** Hottentot golden mole (''Amblysomus hottentotus'')
****** Marley's golden mole (''Amblysomus marleyi'')
****** Robust golden mole (''Amblysomus robustus'')
****** Highveld golden mole (''Amblysomus septentrionalis'')
***** Genus ''Calcochloris
''Calcochloris'' is a genus of mammal in the family Chrysochloridae.
It contains the following species:
* Yellow golden mole (''Calcochloris obtusirostris'')
* Somali golden mole
The Somali golden mole (''Calcochloris tytonis'') is a golden ...
''
****** Subgenus ''Calcochloris''
******* Yellow golden mole (''Calcochloris obtusirostris'')
****** Subgenus ''incertae sedis
' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertain ...
''
******* Somali golden mole
The Somali golden mole (''Calcochloris tytonis'') is a golden mole endemic to Somalia. In 1964, Dr. Alberto Simonetta of the University of Florence discovered the mole's jaw and ear bone fragments in a barn owl pellet in Giohar, Somalia. The Som ...
(''Calcochloris tytonis'')
*****Genus ''Huetia''
****** Congo golden mole (''Huetia leucorhina'')
***** Genus '' Neamblysomus''
****** Juliana's golden mole (''Neamblysomus julianae'')
****** Gunning's golden mole
Gunning's golden mole (''Neamblysomus gunningi'') is a small mammal endemic to South Africa. It was listed in 2006 as an endangered species. Its decreasing numbers are due to habitat clearance or destruction and predation from domesticated cats a ...
(''Neamblysomus gunningi'')
References
{{DEFAULTSORT:Golden Mole
Afrosoricida
Extant Lutetian first appearances
Taxa named by John Edward Gray