Above: African Rock Python. Image Credit: Gardenesign

Many people all over the world have an innate phobia of snakes. It is common to kill a snake on sight regardless of whether they are harmless or not. This natural fear extends far back to the paleocene, and evolutionary biologists even hypothesize that early primates developed advanced visual systems specifically to detect camouflaged, deadly snakes^[¹^,²^]. This fear is present in our very biology as well– neurological studies have shown that the human brain processes visual images significantly faster than images of harmless animals^{[2, 4]}, an ancestral survival trait developed millions of years ago. However, this fear may be causing ecosystem collapse, increased rodent populations, and higher probabilities of disease in many areas.

The African Rock Python (Scientifically known as Python Sebae) is receiving severe population threats in local ecosystems all across Africa due to population loss, poaching, and human-wildlife conflicts^[⁷^,⁸^,⁹^]. This is causing spikes in rodent populations, which in turn damage crops and spread disease^[³^,¹¹^]. Because these snakes are primarily killed near human settlements, rodent populations grow in those areas. These high rodent concentrations in turn further attract African Rock Pythons to these villages^[¹¹^,¹²^]. In this way, the very snakes whom we fear are, in fact, extremely beneficial and essential to their respective ecosystems as well as the surrounding human population^[¹³^,¹⁴^].

The African Rock Python is a species native to sub-Saharan Africa. As generalistic carnivores, their diet consists of rodents, monkeys, warthogs, antelopes, monitor lizards, birds, and occasionally young crocodiles^[⁵^,⁶^]. Averaging 3-5 meters, with some individuals exceeding 6 meters (20 feet), this species is one of the few snakes physically capable of killing and consuming a human (though there are a few historically documented attacks, they are incredibly rare). As humans kill more and more pythons, rodent populations grow rapidly – and more pythons are attracted to the area^[¹⁵^]. As these snakes’ population decreases in human-inhabited areas, prey abundance sky rockets, defiling crops and spreading disease rapidly. These pythons are commonly overlooked for their key place in the ecosystem. As more and more pythons are killed by humans, the ecosystems they once dominated are swung out of balance^[¹⁶^].

The African Rock Python primarily eats small or medium sized animals, such as rodents. These pythons generally consume between 100 and 200 rodents a year^[¹⁵^,¹⁷^]. This rapid consumption is necessary, as rodents commonly reproduce quickly. A standard pair of agricultural rats can reach sexual maturity in just 4 to 7 weeks. Because their gestation period is only around 21 days, a single pair can yield more than 1,250 descendants in just one year without a predator^[³^,¹⁸^]. When an apex predator is removed, an over-abundance of small, fast-producing prey immediately establishes itself. Killing even a single African Rock Python can upset an ecosystem dramatically. As communities lose these apex predators, rodent swarms move directly into the communities, defiling crops and spreading disease in their wake^[¹⁹^,²⁰^]. In turn, more African Rock Pythons move nearer to these communities, following the rodents and posing yet another issue^[¹⁴^,¹⁷^]. Rodent swarms heavily damage food, representing 22% of lost global stores of grain every year^[²¹^,²²^].

A study by ResearchGate proved that when pythons were introduced into an area densely populated by rodents and pests, abundance degraded immediately^[²³^].

Above: Python abundance by year from 2007 to 2022. Image Credit: Research Gate.

Researchers took a graph of python population levels per year (Above) to determine when abundance spiked or fell over the past ~20 years. They found that from 2018 to 2020, rodent populations peaked, while in spike years such as 2016 or 2021, rodent populations heavily decreased. They demonstrate this heavy decline with a graph comparing python counts to mammal counts, specifically raccoons and opossums (Below).

Above: Proportional decline of raccoon and opossum populations as more snakes are introduced. Solid lines: December 2016; Dashed lines: December 2021. Image Credit: Research Gate.

Comparing the two images, we see that between 2018 and 2021, mammal populations increased, before drastically decreasing in 2021 when python populations spiked. These images demonstrate that as python abundance increases, rodent populations heavily decrease, and vice versa.

Without African Rock Pythons, not only are crops heavily damaged by rodents, but incoming swarms of rodents spread dangerous diseases into communities without snakes^[²⁴^,²⁰^]. Zoonotic mammal hosts can infect communities with diseases such as rabies, tuberculosis, lyme disease, hantavirus, and other deadly diseases^[²⁵^]. The below image comparison shows that African Rock Python populations often align with areas highly populated by zoonotic mammal hosts. The presence of pythons in these areas keeps the population of these dangerous hosts moderate, helping to prevent disease from spreading.

Above: Geographic spread of zoonotic (disease-carrying) mammal hosts, such as rodents. Image Credit: Cary Institute. Below: The native range of the African Rock Python. Notice the overlap with the above image.

Summarily, though the African Rock Python’s global status is “Least Concern”, it is increasingly rare and endangered in local communities. The absence of these pythons lead to surges in pest and rodent populations. This abundance of pests destroys crops and spreads dangerous diseases. The presence of African Rock Pythons keeps rodent populations manageable and helps prevent diseases from spreading due to the presence of zoonotic hosts. Without African Rock Pythons, ecosystems become unbalanced. This species is a perfect example of how instinctual fear can get the better of logic, and serves as a reminder to look beyond our fears to protect the animals who protect us.