Red-billed Oxpecker: "Hey, big guy, someone's coming, run!!"

In the African bush, a black rhino is looking for food with its head down, while several red-billed oxpeckers are resting on its back.

This group of birds fly back and forth and climb on its body from time to time, but the black rhino turns a blind eye to this behavior. This is because for large herbivores, there are often lice, ticks, maggots and other parasites in the cracks of their skin or in their wounds, which makes them very uncomfortable. However, these parasites happen to be the favorite food of bullfighting birds , so the black rhino can tolerate the presence of these "cleaners".

In fact, the relationship between the black rhino and the red-billed buffalo is called mutualism in nature. The buffalo can help the herbivores clean the annoying lice and ticks on their bodies; and the large herbivores not only provide them with food, but also indirectly provide them with protection.

However, the latest research shows that the relationship between black rhinos and red-billed bull ravens seems to be more than just mutualism. For black rhinos, bull ravens are more like their "little guards" who will remind them that danger is approaching.

Black rhinos are solitary creatures with poor eyesight and are unaware of danger lurking nearby, making them easy prey for poachers.

In the first half of the last century, black rhinos were the most numerous rhino species in Africa and even in the world. At its peak, there were about 850,000 black rhinos active in eastern and southern Africa.

Historical range of the black rhino

By the beginning of 1990, the number of black rhinos had dropped significantly. According to statistics, there were less than 2,500 black rhinos in the wild at that time. There is no need to explain the main reason for their sharp decline in numbers. Everyone should know that Africa can be said to be the happiest "lawless place" for poacher "Zhang San" .

That's right, illegal poaching fueled by the international rhino horn trade is the biggest threat to the survival of the black rhino , much more serious than habitat changes or other predators (elephants, impalas) stealing food.

However, humans' special liking for black rhino horns is not a one-day thing. According to the document "China and Rhinoceros", as early as 1200 BC, ancient people often hunted black rhinos and removed their horns to make wine glasses, and also peeled the rhinoceros skin to make leather armor and armor; in the Middle East, rhino horns have always been the main source of local decorations, such as the exquisite scabbards and tableware used to make Yemeni double-blade daggers .

However, these demands did not harm the lifeblood of the black rhino population. Under the regulation of nature, their population was able to maintain a relatively stable state. However, in the early 1970s, the demand for black rhino horns in the market increased dramatically, causing their number to drop by 96% between 1970 and 1992.

Because ornaments made of black rhino horns have gradually become a symbol of "wealth and taste" (similar to ivory next door), and there are rumors that black rhino horns can also be used as medicine to help enhance men's "charm", and their prices are rising rapidly.

As a result, poachers are trying to achieve "cherry freedom" by capturing black rhinos.

So, what does the capture of your black rhino have to do with my cattle-raider bird?

In the past, it really didn't matter. At most, it would just be a matter of changing its "master". But the problem is that excessive hunting by humans has led to a significant decrease in the number of black rhinos, which has directly shocked the bull marauders. They have to move to the next master before they have stayed with it for a few days. This has put great selective pressure on the bull marauders .

Therefore, the oxpecker evolved a special "anti-human behavior" - sounding an alarm to alert the black rhino that there is danger nearby. Why is it "anti-human"? Because for other predators (such as hyenas, lions, etc.), the black rhino's "anti-predator behavior" and their weapons (sharp horns and hard skin) can effectively fight large carnivores. Otherwise, how can the black rhino survive to this day?

Unfortunately, these tactics against predators on the grasslands are much less effective for human hunters. Not to mention the use of modern weapons, ancient people did not need to spend much effort to cooperate and use spears to hunt rhinos and easily capture one or even several black rhinos. The "anti-human behavior" evolved by cattle raptors can help black rhinos know the threat of nearby poachers earlier and stimulate their "anti-predator behavior."

The research team from California State University conducted a two-year observation experiment in Hluhluwe-iMfolozi Park in South Africa. During this period, the researchers approached the black rhino 86 times. The results were divided into two groups: when there was no bullfighting bird on the black rhino's back, only 23% of the black rhino detected the danger, and the distance was very close, about 21 meters .

In addition, with these "little guards" on their backs, black rhinos can detect human approach every time (100%), and at a relatively long distance (about 61 meters) . After the bullfighting bird sounds the alarm, the black rhinoceros will immediately become alert (for example, stand up from a resting position), and then they will either continue to remain alert or directly choose to run away.

Interestingly, this experiment also indirectly confirmed the anecdotes and folklore circulated among African hunters that the red-billed oxpecker is an anti-human sentinel of the black rhino. In Swahili, the name of the red-billed oxpecker (Buphagus erythrorynchus) is Askari wa kifaru, which means guard of the rhino .

Although bullfighting birds act as "sentinels" for black rhinos, don't think they are completely kind-hearted. In fact, in addition to eating lice, mites and other parasites on the rhinoceros' body, they themselves can also be said to be parasites on the rhinoceros.

When wounds appear on the rhino's skin, the bullfighting bird can't help but secretly drink some blood, but in order to obtain the alarm information, the black rhino can only endure it.