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Chrysochloris asiaticaCape golden mole

By Shaley Valentine

Geographic Range

Cape golden moles (Chrysochloris asiatica) are endemic to South Africa. They are found from the southernmost portion of the Western Cape, to the northern region of the Northern Cape in a narrow band along the west coast of South Africa. (Bronner, 2012)

Habitat

Cape golden moles live in underground tunnels. They inhabit a variety of soil types ranging from sandy to moist soils mixed with clay, although they cannot inhabit heavily clayed soils. These moles thrive in loose, dry, sandy soils. Cape golden moles are also found in sandy beaches, cities, coastal areas and mountainous regions. Due to habitat destruction, these moles are currently found more frequently in urbanized areas than in the rural soils they prefer. (Bronner, 2012; Jackson, et al., 2009; Scantlebury, et al., 2005; Stuart and Stuart, 2001)

  • Other Habitat Features
  • urban

Physical Description

Cape golden moles do not show sexual dimorphism, they have no external copulatory organs and both genders have a similar body size, with an average mass of 37 to 47 g. Unlike most mammals, they have a cloaca, a common opening for both reproductive and urinary systems. Their penis is contained in the cloaca, while their testes are abdominal. Cape golden moles have streamlined bodies, short forelegs with stout claws, a pointed head, a leathery patch on their nose and no external tail; all features specialized for digging and living underground. Their pelage is dark brown with shades of green or violet depending on the angle of light. Color and body size varies throughout their range, leading to skepticism over whether they have subspecies. They have a thick undercoat and a water repellent layer of fur, which lies in the opposite direction. Two pairs of mammae are embedded in their fur, one inguinal and one thoracic. Generally, moles have a dental formula of 3/3, 1/1, 4/4, 3/3 for a total of 44 W-cusped teeth (dilambdodont dentition). Cape golden moles have larger skulls than Grants golden moles, whose skull dimensions are 26 mm in length by 16 to 18 mm in width. Cape golden moles have no external pinnae because they are furred over. They possess enlarged club-shaped mallei, which allow them to hear seismic vibrations. Their eyes are vestigial and furred over, just like their ears. Surprisingly, these moles have retinas, but no eye muscles and deteriorated irises, lenses and optic nerves. (Bronner, 2012; Gorman and Stone, 1990; Perrin and Fielden, 1999; Willi, et al., 2006a)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    37 to 47 g
    1.30 to 1.66 oz
  • Range basal metabolic rate
    1.17 (low) cm3.O2/g/hr

Reproduction

Very little is known about the mating systems of cape golden moles. Pairs most likely come together as the result of long distance calling generated as ground waves, as this is their main mode of communication. (Willi, et al., 2006b)

The closely related species, Hottentot golden moles, have graafian follicles and corpora lutea for nine months of the year, which suggests that this mole has a fairly equal chance of ovulation and successful reproduction at any time of the year. However, during the wet African summer months when prey are most abundant, golden moles have enhanced follicular development. The increased amount of prey during this time gives moles more energy stores for breeding and increases the survival rate of young. Golden moles have an average of 2 young per litter. (Schoeman, et al., 2004; Stuart and Stuart, 2001)

  • Breeding season
    Golden moles breed year round, particularly during the summer months.
  • Average number of offspring
    two

There is very little information concerning the parental care of cape golden moles. Female moles have two pairs of mammae, one thoracic and one inguinal. The length of nursing and male parental investment is unknown at this time. These moles are solitary, suggesting males do not remain nearby while females care for their young. (Jackson, et al., 2009)

  • Parental Investment
  • female parental care
  • pre-hatching/birth
    • provisioning
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

No information is available on the lifespan of cape golden moles.

Behavior

Cape golden moles forage on the surface or in shallow surface tunnels. These moles can hear seismic vibrations created by their prey at a frequency of approximately 500 Hz. These vibrations travel as R-waves, moving through the boundaries between two mediums, such as air and soil. These moles are very elusive and typically spend most of their time in extensive burrows and tunnels. Their tunnels lead relatively far into the ground and are approximately 200 m long. Julianas golden moles, a close relative, tunnel as deep as 40 cm. Cape golden moles create up to 20 m of surface tunnels daily for hunting grounds. Their stout and sharp forefeet claws and the leathery patch on their nose allow these moles to efficiently dig through the African soil. Cape golden moles enter torpor when the ambient temperature is cool, conserving energy and storing water. During torpor, their body temperature decreases and little activity occurs. These moles have a lower body temperature than other similar-sized mammals, averaging 32.9 C. Golden moles have a very low water turnover rate, basal metabolic rate (BMR) and heart rate to compensate for their fossorial lifestyle. Compared to similar fossorial species, cape golden moles also have lower than predicted energy requirements. Their BMR is low either to accommodate the high energy demands of foraging or to prevent overheating in tunnels on hot days. In either case, they have distinct adaptations to conserve energy and protect themselves from stress, despite their fossorial nature. They are sensitive to ambient temperature fluctuations due to their large surface-area-to-volume ratio, small amount of body fat and rapid heat exchange with the environment. As a result, cape golden moles are active during the morning and at night, the cooler parts of the day. In an ideal habitat, these moles can be found at a density of four per hectare. This relatively low density is due to their solitary lifestyle. These moles adjust fairly well to other habitats, such as developed suburbs where they can be found in gardens. (Bronner, 2012; Gorman and Stone, 1990; Jackson, et al., 2009; Scantlebury, et al., 2005; White, 2003; Willi, et al., 2006a)

Home Range

There is no information available on their home range size.

Communication and Perception

Cape golden moles mostly rely on their senses of hearing and smell. These moles possess vestigial, furred-over eyes that cannot be used as visual systems. They also have no pinnae and their ears are furred over. Instead, they have enlarged mallei, which allow them to sense vibrations produced by prey, predators and other disturbances through seismic waves. These moles are solitary and do not communicate with conspecifics frequently. Distress calls and intra-specific calls range in frequency between 1 to 2 kHz, this is the optimal vibration range for their hypertrophied mallei. According to laboratory tests and dissections, the malleus oscillates around a ligament on the incus at a range of 70 to 200 Hz; this is the range of most seismic vibrations. At a range of 1 to 6 kHz, the ossicular chain rotates around the malleus; this is the range of most air waves. This two way movement of the inner ear bones allows for a greater range of hearing and perception in golden moles. (Gorman and Stone, 1990; Scantlebury, et al., 2005; Willi, et al., 2006b; Willi, et al., 2006a)

Food Habits

Cape golden moles are insectivorous, eating mostly insects and other small invertebrates, although they have also been documented eating small lizards. They typically forage on the ground surface or in tunnels at night, dawn or twilight. Ground vibrations created by their prey are detected by the mole’s hypertrophied mallei. Less commonly, cape golden moles can be found on sandy beaches foraging for isopods and amphipods, two types of crustaceans. (Bronner, 2012; Stuart and Stuart, 2001; Willi, et al., 2006b)

  • Animal Foods
  • reptiles
  • insects
  • terrestrial non-insect arthropods

Predation

Golden moles are preyed upon by owls in their natural habitat. Due to habitat destruction in South Africa, they can now be found in suburbs and cities where cats and dogs may prey on them. To avoid predation, these moles listen to ground vibrations. When vibrations are detected, they know to stay away from the source of the sound. Cape golden moles remain in their tunnels most of the day, but do venture onto the ground surface when nocturnal or crepuscular predators are active. Their fur is typically a light to medium brown, which serves as camouflage in desert and coastal soils. (Bronner, 2012; Perrin and Fielden, 1999; Willi, et al., 2006a)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

These moles prey on insects that could potentially be harmful to other animal and plant species. They also play a role in soil turnover as they dig, which helps incorporate air and nutrients into the soil. As these animals are fairly cryptic and spend the majority of their time in burrows and tunnels, moles are not a major source of food. (Jackson, et al., 2009)

Economic Importance for Humans: Positive

Cape golden moles provide little economic benefit; however, they eat pest insects that harm garden plants. (Bronner, 2012)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

These moles dig up soil when they burrow, making them a nuisance to homeowners. (Bronner, 2012)

  • Negative Impacts
  • crop pest
  • household pest

Conservation Status

Cape golden moles are currently listed as a species of Least Concern on the IUCN Red List of Threatened Species. They adapt fairly easily to new areas, which is beneficial considering the large amount of development, habitat destruction and fragmentation occurring in their natural territories. Many areas where these moles occur are nationally protected, however, given their hardy nature, there is not a need to protect more lands for this species. (Bronner, 2012)

Contributors

Shaley Valentine (author), Northern Michigan University, John Bruggink (editor), Northern Michigan University, Leila Siciliano Martina (editor), Animal Diversity Web Staff.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

insectivore

An animal that eats mainly insects or spiders.

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

soil aeration

digs and breaks up soil so air and water can get in

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

urban

living in cities and large towns, landscapes dominated by human structures and activity.

vibrations

movements of a hard surface that are produced by animals as signals to others

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

References

Asher, R., S. Maree, G. Bronner, N. Bennett, P. Bloomer, P. Czechowski, M. Meyer, M. Hofreiter. 2010. A phylogenetic estimate for golden moles (Mammalia, Afrotheria, Chrysochloridae). BMC Evolutionary Biology, 10/69: 1-13. Accessed January 29, 2013 at http://www.biomedcentral.com/content/pdf/1471-2148-10-69.pdf.

Bronner, G. 2012. "IUCN Red List of Threatened Species" (On-line). Chrysochloris asiatica (Cape Golden Mole). Accessed January 29, 2013 at http://www.iucnredlist.org/details/40600/0.

Gorman, M., R. Stone. 1990. The Natural History of Moles. Ithaca, New York: Cornell University Press.

Hickman, G. 1990. The Chrysochloridae: studies toward a broader perspective of adaptation in subterranean mammals. Progress in Clinical and Biological Research, 335: 23-48. Accessed January 30, 2013 at http://europepmc.org/abstract/MED/2408075/reload=0;jsessionid=t4zJGx0qlSQ0cS8SUvv0.0.

Jackson, C., T. Setsaas, M. Robertson, M. Scantlebury, N. Bennett. 2009. Insights into torpor and behavioural thermoregulation of the endangered Juliana's golden mole. Journal of Zoology, 278/4: 299-307. Accessed January 28, 2013 at http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.2009.00575.x/full.

Perrin, M., L. Fielden. 1999. Eremitalpa granti. Mammalian Species, 629: 1-4. Accessed January 28, 2013 at https://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-629-01-0001.pdf.

Scantlebury, M., M. Oosthuizen, J. Speakman, C. Jackson, N. Bennett. 2005. Seasonal energetics of the Hottentot golden mole at 1500 m altitude. Physiology & Behavior, 84/5: 739-745. Accessed January 28, 2013 at http://www.sciencedirect.com/science/article/pii/S0031938405000739.

Schoeman, S., N. Bennett, M. Van der Merwe, A. Schoeman. 2004. Aseasonal reproduction in the Hottentot golden mole, Amblysomus hottentotus (Afrosoricida : Chrysochloridae) from KwaZulu-Natal, South Africa. African Zoology, 39/1: 41-46.

Stuart, C., T. Stuart. 2001. Field Guide to Mammals of Southern Africa. Cape Town, South Africa: Struik Publishers.

White, C. 2003. The Influence of Foraging Mode and Arid Adaptation on the Basal Metabolic Rates of Burrowing Mammals. Physiological and Biochemical Zoology, 76/1: 122-134. Accessed January 29, 2013 at http://www.jstor.org/stable/10.1086/367940.

Willi, U., G. Bronner, P. Narins. 2006. Middle ear dynamics in response to seismic stimuli in the Cape golden mole (Chrysochloris asiatica). The Journal of Experimental Biology, 209: 302-313. Accessed January 27, 2013 at http://jeb.biologists.org/content/209/2/302.full.pdf.

Willi, U., G. Bronner, P. Narins. 2006. Ossicular differentiation of airborne and seismic stimuli in the Cape golden mole (Chrysochloris asiatica). Journal of Comparative Physiology A, 192/3: 267-277. Accessed January 30, 2013 at http://link.springer.com/article/10.1007%2Fs00359-005-0070-9?LI=true.

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