Giant golden mole  (Chrysospalax trevelyani)

The giant golden mole is classified as Endangered (EN) on the IUCN Red List (1).

As its common name suggests, the giant golden mole (Chrysospalax trevelyani), at 23 centimetres in length, is by far the largest of the golden mole species (3). Yet contrary to its name, the giant golden mole is in fact a dark, glossy brown (4). The word ‘golden’ comes from the family name Chrysochloridae (derived from Greek, meaning green-gold), which refers to the iridescent sheen of the coat (2).

Like other golden mole species, the giant golden mole is well adapted to its subterranean lifestyle. It possesses robust claws on its forelimbs for digging underground, whilst its hind limbs bear five webbed digits for shovelling the loose soil backwards. The lack of external ears or tail creates a more compact, streamlined body for moving underground. In addition, the giant golden mole has a wedge-shaped head and a leather pad on its nose, which protects its nostrils as it pushes through the soil (5). Most strikingly, all golden moles lack external eyes (5), likely to be a result of their subterranean lifestyle.

With a longer, coarser coat than other golden mole species, the giant golden mole has woolly underfur which helps to keep it insulated, and guard hairs which repel moisture (2) (6). The dark and glossy upperparts give way to paler, yellowish underparts, and on its head are small, lighter coloured patches, where eyes and ears would typically have been situated (6).

Vocalisations are seldom used by the giant golden mole, although adults may make soft puffing and chirping sounds, especially during courtship, and young have been heard squeaking when alarmed (3).

The giant golden mole is endemic to South Africa, where it inhabits a restricted area in the Eastern Cape. It is only present along a narrow stretch of coastline from East London northwards to Port St Johns and then inland to Amathole (1).

The giant golden mole is associated throughout its range with indigenous coastal and montane forests (1), while occasionally residing in adjacent grassland (7). The giant golden mole has very specific habitat requirements, being present only in forests with soft soils, deep leaf litter layers and well-developed undergrowth (1).

In contrast to other species of golden mole which construct semi-permanent tunnels for foraging underground, the giant golden mole feeds on the surface, foraging in the leaf litter (3). It excavates burrows up to 13 metres long among the roots of trees, which are connected to other burrows by well-defined tracks on the surface. From these tracks, smaller paths meander through the leaf litter, where the giant golden mole preys mainly on millipedes and giant earthworms (7).

The giant golden mole is primarily nocturnal, emerging at night to feed, although in cool and cloudy conditions it may forage during the day (3). Golden moles are generally solitary and territorial, and while the giant golden mole is also likely to be typically solitary, it is the only species of golden mole that has been reported to show some social behaviour, with groups hibernating in the same burrow during the winter months (5).

Little is known about the reproductive cycle of the giant golden mole. It has small litter sizes, consisting of one or two young which are probably born during the rainy season when there is a plentiful food supply (3).

The main threat to the giant golden mole is habitat loss. The fact that it requires such a specific habitat has left it vulnerable to human-inflicted habitat degradation and fragmentation. Commercial forestry plantations have replaced large areas of indigenous forest, and firewood collection, bark stripping, the cutting of saplings for hut construction, and overgrazing by livestock have also caused a dramatic reduction in available habitat (5).

With an expanding human population, urbanisation and coastal tourism developments also pose a serious threat to the giant golden mole, especially near East London (1).

Another consequence of urbanisation is that this species is more frequently preyed on by feral dogs, and although the giant golden mole inhabits some protected conservation areas, only one of these is fenced off to exclude dogs (8).

The fate of the giant golden mole remains uncertain, as although it may occur in a few protected reserves, there are currently no targeted conservation actions underway to protect this species. Research is needed in order to assess the status and viability of the remaining populations (1).

Further information on the ecology and biology of the giant golden mole would help to facilitate and tailor effective conservation efforts for this species (9). It has also been recommended that tighter control of the remaining habitat should be implemented to protect the forests that this species depends on for its survival (8).

Find out more about the giant golden mole:

• The IUCN/SSC Afrotheria Specialist Group - Golden moles:
  http://www.afrotheria.net/golden_moles/
• EDGE of Existence - Giant golden mole:
  http://www.edgeofexistence.org/mammals/species_info.php?id=118