Spotted! One of our rarely seen underground critters the Cape Molerat. Molerat? What an interesting name considering that they are neither mole nor rat. Molerats are fossorial (adapted to a life of digging and lives primarily underground) rodents that are more closely related to guinea pigs and porcupines. The Cape Molerat is endemic to South Africa and one of three species of molerats in the fynbos biome of the southwestern Cape. The Cape Molerat is easily identifiable from other molerats with its distinct white patches along the face and head and a rusty brown coat. Molerats have unique long incisors that protrude outside of the mouth. Unlike moles that primarily use their specially adapted feet to burrow under the ground, molerats dig with their incisors. These amazing teeth don’t just dig, but also help the animal feel and sense its environment. Their lips are specially adapted behind their incisors to prevent soil from entering while they burrow.
While moles rely on an insectivorous diet, molerats are herbivores feeding on underground plant material like bulbs, corms and tubers. They dig special foraging tunnels different from their main tunnelled habitats to reach plant roots. They may even dig special storage chambers to store food when access to food becomes difficult or while females care for their young.
Some species of molerats may display eusocial behaviour (extreme social bonding) like termites and bees. But the Cape Molerat is a solitary animal that only comes together for reproduction.
They may share a burrow while the female is raising young. But by seven weeks of age, they establish their own burrows and may become highly aggressive towards one another outside of the breeding season.
You may think that because they live underground, they are blind, but, although, their eyes are quite small they are functional.
When the animals leave their tunnels to forage on surface vegetation or disperse to look for new burrows they can see well enough and turn into their fighting stance (showing off their incisors) to repel approaching threats.
These animals are excellent ecosystem engineers! They play a fundamental role in shaping fynbos vegetation by enhancing species richness due to causing higher concentrations of nitrogen and magnesium in soils where they are active, as well as increasing the drainage and moisture-holding capacity of the soil.
The Fossil Park is a wonderful contrast between the new and the old. Molerat fossils, dating to 5 million years ago, have been found in an unusual high abundance at the Fossil Park. They are not often found in high concentrations at other fossil sites. Molerats and many other small animals like other rodents, small birds, reptiles and amphibians form part of the microfaunal fossil assemblage. Unlike the bigger fossils, which are more easily observed, you must carefully search for the small bones using a sieve to help separate them from the sand and then, using a microscope to help see distinctive features you are able to determine whether you have a new species or not. This of course requires attention to detail and lots of patience but is guaranteed to be rewarding and therapeutic as well.
Amouré Robinson is the Acting Head of Public Programmes of WCFP.
*This article forms part of a series of articles on the West Coast Fossil Park.
