The marsupial or golden mole is a little known Australian animal. The reason there is little information surrounding the marsupial mole is that they inhabit arid, isolated areas and are fossorial. Fossorial animals are animals that burrow. There are two known species, Notoryctes typhlops and Notoryctes caurinus. N. caurinus is also referred to as the kakarratul. They are a living fossil, a term given to organisms that are seemingly prehistoric and often closely linked to fossils on display in museums.
Notoryctes typhlops has the characteristic body type of a burrowing animal. It is of a small size as its head to body length is 140mm and weighs approximately 60g. The extremities are shortened and the ear pinnae (the part of the ear that sticks off the side of your head) and external eyes are absent. The body bears resemblance to a cylinder and is covered in dense cream to white hair. Hair may appear golden to red but that is due to the iron oxides (rust) present in the ground matter it burrows in. Its pouch opens posteriorly to avoid it being filled with sand. They also have heavily keratinised skin (really thick like the paw of a dog) on their nose.
The marsupial mole has a number of remarkable characteristics. For instance, they have asymmetrical teeth (Figure 1 and 2) and are zalambdonts. A zalambdont is an animal with short molar teeth with a single Λ- or V-shaped ridge. The roots of the teeth are only one third of the length of the molar which means they are not strongly implanted in the gum. Therefore, N. typhlops can not chew hard substances.
Their method of reproduction is assumed to be standard of marsupials. The exception being the testes of the male are between the skin and the abdominal wall and are prepenial meaning the testes are at the same level as the anterior pubic bones (testicles don’t hang outside of the body). Pouch young has been obtained but neither copulation or pregnancy has been observed. Very little is known about gestation (pregnancy) or life of the pouch young.
Studies on N.typhlops is difficult because they do not adapt well to life in captivity. Previous specimens in captivity have died of pneumonia and hypothermia. Few specimens arrive still live to biologists.
Sighting of marsupial moles generally occur on sand ridges and plains that contain spinifex. Diet of these marsupials has been determined by examining gut contents and food stuffs consumed by captive specimens. From these studies it was deduced the N. typhlops is an insectivore with a preference for eggs, larvae and pupae. Captive animals were found to be uninterested in beetles but reports have been made of the consumption of centipedes, spiders and geckos.
Due to the secretive habits of the marsupial mole very little can be learnt of natural history. Do they have a social structure? Are they polygynous or polyandrous (how many wives or husbands are they allowed)? Are there more than the two known species of marsupial mole? How many young do they have? What age to they live to? At what age can they breed? How do they communicate with each other? How many moles are there? For all that we know the moles may have a thriving society beneath the dunes and we have only been in contact with those that essentially ‘beach’ themselves like whales on the diminishing shore line. Therefore, how can we know if their population is increasing or decreasing? Perhaps they have always had low numbers.
Absence of historical population levels is not unique to the marsupial mole. The komodo dragon is an excellent example of the same situation. Their population is relatively stable on the island of Komodo where they are the apex predator but they are slow to breed and there are approximately only 3000 in the wild. What is not known is have there only ever been 3000 dragons? If so then the komodo dragon can not be traditionally classified as a threatened species. If there were once 50,000 individuals and now only 3,000 then yes it could be considered threatened. Small populations are more vulnerable to negative factors than larger populations but do not necessarily mean the species is about to go extinct. So if there are only 1000 marsupial moles in the wild and there have always been 1000 then do we need to worry about them? The trick though is that we do not know what their population was before European settlement and we do not know their population now. Do we have an as yet undiscovered thriving population? Or far more likely, do we have a species about to go extinct? We do not know…. Yet another animal is potentially about to leave the face of the Earth and we know nothing of it. This is sounding all to familiar to the gastric brooding frog I previously wrote on.