Ecology of mosaic-tailed rats

Well, I nearly missed February, but here we are, and 2020 is just flying by. Thoughts of holidays are in the past and all of us are now busy busy busy! Already it’s so close to the start of the University semester that I find myself really wondering where the time has gone. But enough of that! We’re here to continue talking about fawn-footed mosaic-tailed rats Melomys cervinipes (Figure 1). Hopefully, by now, you’ve realised that their biology is pretty cool, if somewhat complicated. So now we’re going to take a closer look at other aspects of these amazing little animals, starting with their ecology.

Fig. 1. Fawn-footed mosaic-tailed rat Melomys cervinipes

So let’s start off with the population characteristics (or at least what’s known from the literature).

Population density can vary from about 0.08 – 0.4 individuals per hectare in rainforest fragments.

However, in sclerophyll forests, population density can be higher, around 0.88 – 1.27 individuals/ha.

It seems that abundance starts to increase when vines and leaf litter increase, or when the quantity of climbing plants, sub-canopy and ground cover increases. Now this makes sense because mosaic-tailed rats are arboreal, so things that make it easier to climb to the canopy to find more resources would be beneficial. Likewise, increase of ground cover reduces the likelihood of being spotted by predators, also providing a survival advantage. Indeed, mosaic-tailed rats seem to do quite well in disturbed areas and on forest edges.

Fig. 2. Tropical rainforest. Photo: Ben Britten

Typically, mosaic-tailed rats are associated with cool, dark, damp conditions of continuous forest (Figure 2). However, their habitat preferences do become less restricted as they progress southwards in their distribution. They can be found in wetter, but more open forests, wet sclerophyll rainforest, subtropical rainforest, warm-temperate rainforest, forest fragments, grassy open forest adjacent to rainforest, open shrubland dominated by dry, tall eucalypt species on sandy soil, closed palm forests, coast mangrove forests and cane fields adjacent to forests. Mosaic-tailed rats prefer structural complexity. They will use both the forest floor, as well as vertical forest layers up to around 16 m above the forest floor. They’ll spend up to 30-90% of their time travelling in the canopy. Generally, they will only travel short distances, although they can travel kilometres if needs be. Range length is generally only about 80 m or so, which lengthens in winter as food becomes harder to find, but shortens in summer as food becomes abundant. Home range size for both sexes is about 0.42 ha, but the core area of activity is much smaller, only about 0.09 ha.

Fig. 3. Mosaic-tailed rat eating. Photo: Unknown

Mosaic-tailed rats are dietary generalists. Being primarily herbivorous, they feed on foliage and vegetation, but also on fruits, seeds, fungi and flowers (Figure 3). They may take insects, although observations from captive animals suggest that this is not common. In addition, they will eat human food products. I have found that banana chips are a particularly favoured treat for captive individuals. There is evidence for regional differentiation in diet, which makes sense, as plant distributions vary regionally too. There is also evidence for differentiation in diet depending on disturbance state, with mosaic-tailed rats living in forest edges typically having a higher proportion of fruits, leaves and flowers in their diet.

In the next blog, we’ll continue focusing on the ecology of mosaic-tailed rats.

You can read more about my research in my publications, listed on my blog. You can also find me on ResearchGate, the James Cook University website, Twitter and Facebook.