Amblysomus robustusrobust golden mole

Geographic Range

Robust golden moles (Amblysomus robustus) are native only to South Africa. Although they are most frequently seen in the eastern Mpumalanga Highveld, their range is determined mostly by the known distributions of other similar species endemic to the area.

Habitat

Robust golden moles are not particularly selective about their habitat. They have been found in marshes and grasslands of the Steenkampsberge mountains mainly, but also in developed areas near human activity (such as gardens and farmlands). They are terrestrial and fossorial, and are commonly found in South African grassland biomes.

  • Average elevation
    2,330 m
    ft

Physical Description

Robust golden moles have been recorded as having a total length of 109 to 143 mm and a mass of 61 to 98 g. There is a significant variability in size due to sexual dimorphism (as males have larger skull sizes and wider third foreclaws). Variability also exists between populations at differing altitudes and climates. Populations of robust golden moles increase in mean size as altitude increases or as mean temperatures fall. Robust golden moles are distinguishable from similar species of the genus Amblysomus by the prominent third foreclaws of males. Their foreclaws are larger in width when compared to Highveld golden moles (A. septentrionalis) and Hottentot golden moles (A. hottentotus). Female robust golden moles are harder to distinguish from other species as there is little recorded difference between physical measurements.

Robust golden mole coloration varies between adults and juveniles. Adults have reddish-brown fur along all of their bodies except for their ventral surface, which is orange. Juveniles are greyish-brown dorsally, orange on their flanks (a slightly duller hue than adults), and orange ventrally (just like adults).

Robust golden moles have no external eyes or visible ears. They have prominent foreclaws and a hard, flat nose that helps them move through fossorial environments.

  • Sexual Dimorphism
  • male larger
  • Range mass
    61 to 98 g
    2.15 to 3.45 oz
  • Range length
    109 to 143 mm
    4.29 to 5.63 in

Reproduction

Due to the solitary nature of robust golden moles, adults defend potential mates fiercely from challengers intruding into their territory. Socially, this leads to isolation among members of the population. Both sexes have cloacae, and males have internal penises and testes.

Due to the scarce observation of robust golden moles, much of the information regarding reproduction is based on research into closely-related species. Females breed year round. They give birth to 1 to 3 young in underground, grass-lined nests. Courtship between robust golden moles is often violent. Increased breeding is observed during stretches of heavy rainfall, due to an increase in food sources. In these periods, individuals are more active and are more likely to encounter mates.

  • Breeding interval
    All year

The extent of parental care that robust golden moles provide for their young is relatively unstudied. However, due to scarcity of resources and low predation, it is believed that both parents support juveniles for a short amount of time. Closely-related Hottentot golden moles (Amblystomus hottentotus) provide milk for their young until they are about 35 to 45 g, after which they are forced out of their burrow.

Lifespan/Longevity

Lifespan for robust golden moles is unknown in this species and related species due to poor research funding, the nature of fossorial species, and difficulty navigating the landscapes in which they live.

Behavior

Robust golden moles are very solitary. They are highly active, using their large foreclaws to move through the sand and hunt for food. Robust golden moles are extremely territorial and violent.

Home Range

Home range for robust golden moles is unknown, due to lack of research.

Communication and Perception

Little is known about Robust golden mole communication, as they are generally isolated. However, closely-related species have been observed chirping to each other, which may be indicative of how robust golden moles communicate.

Food Habits

Robust golden moles have not been observed to have particular eating habits correlating to different parts of the day. They eat small insects, earthworms and possibly other burrowing prey. They rely heavily on their sense of hearing while underground, where they can detect faint vibrations in the surrounding soil.

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
    • insectivore
    • eats non-insect arthropods
    • vermivore
  • Animal Foods
  • insects
  • terrestrial worms

Predation

Robust golden moles do not have defined predators (due to their complex burrowing patterns and low population density).

Ecosystem Roles

Not much is known about robust golden moles and their interactions with other members of the ecosystem. Aside from preying on small insects and burrowing vertebrates, it is believed that they do not often interact with other species, due to their reclusive lifestyle.

Economic Importance for Humans: Positive

There is no known economic importance that robust golden moles provide for humans. There has been no documentation of using them for any type of trade.

Economic Importance for Humans: Negative

There are no known negative effects of robust golden moles on human activity. When creating new burrows, excavated soil is left in small “mole mounds”, which may be a nuisance in farmlands in which they are commonly found.

Conservation Status

The IUCN Red List lists robust golden moles as vulnerable. They are not listed on the United States Federal list or on CITES.

Other Comments

Robust golden moles are aptly named due to their significant size difference when compared to closely-related species. They are endangered by mining in South Africa and, due to their sensitive sense of hearing and vibrations, are often confused and disoriented by human activity that creates vibrations in the soil. Robust golden moles have been most extensively researched within a protected wildlife area that takes regular steps to maintain proper environmental conditions and limit human interaction.

Contributors

Andrew Loisel (author), University of Washington, Laura Prugh (editor), University of Washington, Galen Burrell (editor).

Glossary

Ethiopian

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

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

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

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.

male parental care

parental care is carried out by males

marsh

marshes are wetland areas often dominated by grasses and reeds.

motile

having the capacity to move from one place to another.

native range

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

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

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

year-round breeding

breeding takes place throughout the year

References

"IUCN Redlist" (On-line). Accessed May 14, 2019 at https://www.iucnredlist.org/search.

"The Red List of Mammals of South Africa, Lesotho and Swaziland" (On-line).

Bronner, G. 2013. Mammals of Africa, Volume I: Introductory Chapters and Afrotheria. London UK: Bloomsbury Publishing.

Bronner, G. 2000. New Species and Subspecies of Golden Mole. The Red List of Mammals of South Africa, Lesotho and Swaziland. Accessed May 14, 2019 at https://www.ewt.org.za/wp-content/uploads/2019/02/4.-Robust-Golden-Mole-Amblysomus-robustus-Vulnerable.pdf.

Ciszek, D., P. Myers. "Chrysochloridae" (On-line). Animal Diversity U Mich. Accessed May 14, 2019 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Chrysochloridae.html.

Mason, M. 2003. Morphology of the middle ear of golden moles. Journal of Zoology.

Mills, G., I. Hess. 1997. The Complete Book of Southern African Mammals. Stuik Publishers.

Rampartab, C. "Facilitating golden mole conservation in South African highland grasslands: a predictive modelling approach" (On-line).