Carpet Pythons as Predators of Koalas

Carpet pythons are one of the top predators of koalas. They account for almost 12 percent of the total deaths by koala predators. Many studies conducted across the Australian continent indicate that after dingoes & wild dogs, carpet pythons are the second-largest predators of koalas. Unfortunately for koalas, carpet pythons can predate them not only on the ground but on trees as well. Therefore, escaping from this predator is rather a matter of luck for koalas. The only advantage koalas have against carpet pythons is that koalas are a bit faster than carpet pythons as pythons take time to climb trees. And they climb in stealth mode.

Interestingly, carpet pythons only prey on koalas during the summer season. There has been no case of a carpet python killing or eating a koala during the winter season. The carpet pythons are usually in the state of brumation during the winter season which is similar to hibernation but not exactly the same. Being cold-blooded animals, carpet pythons need heat to boost their metabolic level. This only becomes available to them during the summer season. Therefore, at least during the winter season, koalas are safe from carpet pythons' predation.

Carpet Pythons Predating Koalas

Statistic	Percentage
Overall Predation	12 percent
Predation for Food	38 percent
Predation for Kill	62 percent
Predation in Bushlands	100 percent
Predation of Joeys	70 percent
Predation in Summer	100 percent

Both Koalas and carpet pythons sometimes but not always live in a shared territory. But in many cases, it becomes a common phenomenon depending on the location. Carpet pythons most commonly reside in Australia's bushlands and near arid areas. This means that Northern Queensland, New South Wales, Northern Territory, and Western Australia are one of the key hubs of the carpet pythons. Koalas also live in the same territories. Koalas are usually safe from pythons when they are on trees. Carpet pythons are semi-arboreal which means that they can climb trees or live on land whenever required. They do climb trees for hunting, sun-basking, and resting.

What kind of koala age groups are vulnerable to carpet pythons? According to several sources, young koala joeys are particularly vulnerable to carpet pythons. They are of perfect size to be eaten by these carpet pythons. However, the adult koalas are not safe from carpet pythons' predation either. But keep in mind that koalas also have sharp teeth and they can inflict a deadly wound on carpet pythons.  It can be speculated that male koala joeys are kicked out of the territory by the dominant male koalas, and in search of a new territory these roaming joeys become easy prey to predators including carpet pythons.

Upon killing koalas, carpet pythons don't always eat them. According to one study carpet pythons didn't eat 62% of koalas after killing them. This opens another level of discussion as, to why carpet pythons don't always eat them after killing. There may be many factors behind this kind of behavior of carpet pythons. The first key reason for not eating a koala might be that the koala is too large for the python to consume. Secondly, a python might consider a koala a threat to its habitat and kill it solely for that reason. Lastly, a python may not eat a koala after killing it because it might have felt threatened by its surroundings.

How do carpet pythons kill koalas? Carpet pythons are not poisonous like snakes. However, they do bite koalas. The bite of the carpet pythons is u-shaped and because of the heavy fur of koalas, this bite is not very easy to detect. Most commonly they bite within the head areas of koalas. This bite helps carpet pythons to maintain a firm grip on koalas. Onwards, they wrap their body around koalas and strangle them to death. Can koala escape death even after being bitten by a carpet python? Yes. There has been at least one reported case of a female koala that was bitten by a carpet python but recovered and was successfully sent back to its habitat.

Lastly, carpet pythons are the indigenous predators of koalas. Being natives of the Australian continent these pythons have been living at the Australian continent for millions of years. Their predation always remains a key factor in Australia’s ecosystem. This also means that koalas serve as a significant proportion of their diet throughout all these years. However, their diet is quite diverse as they prey on large variety of small mammals, birds, and other reptile species.

References

1. Predation by carpet pythons (Morelia spilota) is an important cause of mortality in a free-living koala (Phascolarctos cinereus) population in South East Queensland, 2019. Australian Veterinary Journal, 97(7), pp. 243-250.
2. Ellis, W. A. H., Melzer, A., Carrick, F. N., & Hasegawa, M., 2002. Tree use, diet and home range of the koala (Phascolarctos cinereus) at Blair Athol, central Queensland. Wildlife Research, 29(3), pp.303-311.
3. Lunney, D., & Leary, T., 1988. The impact on native mammals of land-use changes and exotic species in the Bega district, New South Wales, since settlement. Australian Journal of Ecology, 13(1), pp.67-92.
4. Phillips, S., & Callaghan, J., 2011. The Spot Assessment Technique: a tool for determining localised levels of habitat use by koalas Phascolarctos cinereus. Australian Zoologist, 35(3), pp.774-780.
5. Natusch, D. J. D., & Lyons, J. A., 2012. Distribution, ecological attributes and trade of the New Guinea carpet python (Morelia spilota) in Indonesia. Australian Journal of Zoology, 59(4), pp.236-241.
6. Phillips, S., & Callaghan, J., 2011. The Spot Assessment Technique: a tool for determining localised levels of habitat use by koalas Phascolarctos cinereus. Australian Zoologist, 35(3), pp.774-780.