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Humans and wild animals live in the same cities. Is it alliance or rivalry?

Green corridors to host animals and protected cavities in places where migratory birds can nest. The complications of urban ecosystems – from the foxes of Rome, the crows of Tokyo and the lizards of Mexico City

Dining companions is the term used by ethologists to refer to animals that live on food waste from other species. In the Old Stone Age, the mouse and the house sparrow lived on rafts that carried the flint found in the villages of their place of habitat. As consumption exploded over the last century, waste has increased — an attraction for animals that have evolved over the centuries in the food-procuring system. There are many wild animals in the city, but few species — mainly birds and mice. This leads to an imbalance in the city’s ecosystem.

«Bats, foxes, wild boars cyclically visit the city. This depends on the changing of the conditions of the ecosystems where they live» explains Enrico Alleva, an ethologist at Rome’s La Sapienza University. «The less ‘neophobic’ species, that is, who are less afraid of novelty, go in and explore urban spaces. Mammals do so at certain hours of the night when the city is empty, and stealthily manage to enter. The wild boar is an exemplary case. For hunting purposes, hunters have imported prolific species from Eastern Europe. In some years, mothers with many young children look for food and go into the city in search of waste». With globalization, people and goods have brought with them many weeds. Many insects arrived with the food. The red awl, a beetle native to Asia, is a dangerous parasite. «There is a risk that alien species will change the natural system, and it is complex to provide control systems to stop them».

The animals regained their place during Covid-19’s lockdowns. Can you imagine keeping the cohabitation alive even after the blockade? «On the one hand, people in the windows noticed animal species they had not seen before, such as the blackbird or the finch. On the other hand, animal species have not found any more food in parks or on the sides of the streets. Green corridors must be provided in cities, where nature is pre-eminent, and these species can find a place to stay. There is an open debate, even in the community of ethologists and zoologists. There are some who have a more conservative position and want to maintain the current state, while others promote interventions such as laying nest boxes to help some species of birds of prey or bats or systems to make wasps and bees nests. There are no absolute rules, there is a danger of creating artificial situations, where without the intervention of the human species animals cannot feed themselves». 

Dakhama in Malabar Hill, drawing, Bombay

According to Enrico Alleva, «the botanist has his own preferences, more ornamental, the entomologist and the ornithologist prefer shrub species or flowers that promote the nesting of some birds. You must keep in mind the natural history of the area, consulting the scientific literature or even paintings and photos, to understand what the typical animal and plant species over the centuries have been. Put back what was there, without being too conservative. Palm trees, linked to European colonialism, are species that do not reproduce in Italy». The city is made up of buildings: «An element must be considered in the design of our buildings: protected cavities are needed where migratory birds can nest. Flowers and plants useful to bees are also needed, such as the tulip, the mauve, the sunflower, or the marigold». 

Design the city with the eyes of other animal species. A revolution that from anthropocentrism moves towards biocentrism. The urban planning of the future should not focus on forms that deny the presence of homo sapiens but will have to deal with implementing the necessary conditions for coexistence between different animals and plant species. This is the concept behind the Milan Animal City research run by the Polytechnic University of Milan. The studio looks at the Lombardy city from the point of view of the animals that inhabit it. Nesting Milan aims to build a modular structure along the railway lines to accommodate species of birds and plants — a nest infrastructure, which becomes a connective tissue between Milan’s city center and the developing neighborhoods, which the railway tends to separate. The project Bombing Park Sempione focuses on the paradox: whatever man does to make room for nature is still a human act. The result is a cynical project that imagines bombing Sempione Park, an example of an artificial nature, deprived of that unpredictability that makes it different from the city of man; bombing domesticated nature to artificially introduce a wilderness.

Italian cities have been home to species of wild animals for centuries. Villa Pamphilj in Rome welcomes specimens of the fox, an omnivorous mammal, although classified as carnivorous. Its diet is based on a variety of species: invertebrates, eggs, reptiles, small mammals, and amphibians. Among the vegetables it feeds on are berries and other types of berries. It can also feed on carcasses. For this reason, it finds its ideal habitat in the park of the villa: the urban green spaces close to the dwellings have always been populated by them, inserting themselves into the food chain and the waste chain. Most of Villa Pamphilj’s foxes do not show up. Only two showed themselves with daily constancy to the visitors of the villa, seeking the collaboration of man to feed and survive. In Milan, at least eight pairs of the Gheppio falcon have been found to feed on rodents, insects, reptiles, and small birds. The known nests are located in the vault of the Central Station, on the roof of the hospital in San Paolo, and on a tower of San Siro.

The horned lizard chose Mexico City as the city to live in. It is recognized by the rows of thorns that run on the sides of its body, up to the hips and top of the head. It has a body that does not exceed nine centimeters in length, inhabits forests and bushes. To defend itself, it uses pulmonary swelling — it sucks air and swells: the spines rise, and the predator cannot swallow it. Another form of defense: a jet of blood squirts from the eyelids and hits the predator in the eye. Sightings in Mexico City occur mostly on the mountainside of the city’s southern border, around the neighborhoods of San Miguel Ajusco and Pedregal. In these areas, lizards find an environment where their predators, including the coyote, do not live. In Manaus, a Brazilian metropolis in the rainforest, monkeys are the largest group. Tamarins appear, almost every day, on the streets of the city, along with squirrel monkeys, hunting for food in restaurants and bars. Citizens have organized veterinary clinics to rescue distressed animals. The city of Tokyo receives about six hundred calls a year from residents who have been attacked by crows. It happens in the spring, at the time when the birds hatch their eggs and raise the young. In the mid-1980s there were more than 7,000 in the city’s parks. They are now at 30,000. The administration has installed traps to catch some of them.

Rhizome, Milano Animal City, Politecnico di Milano

Fredi Devas, documentary filmmaker and producer of the BBC documentary series Planet Earth II, spent four years learning about animals living in many of the world’s most urbanized areas. «It’s hard to tell whether wild animals and metropolises are competing or co-existing», explains Devas. «The question is what value we give to the animals that live in our cities. When I heard about the hyenas living on the streets of Harar, Ethiopia, I could not believe it. According to legend, when the city walls were built, the ‘doors of hyenas’ were created, not large enough to allow the entry of opposing soldiers, but big enough to let a hyena in. Two herds of hyenas entered the city through these doors every night, looking for bones left outside the butchers. As I walked down a small street in the old town, I saw hyenas passing by me, touching my leg. I was meat for them: animals of ninety kilos could have jumped on me in seconds, but they did not. A few darkened nights later I filmed the two herds of hyenas fighting for access to the city. Over a hundred hyenas were fighting around my feet and somehow my fear had disappeared. The peaceful pact between humans and hyenas in this city was obvious, I did not feel in danger. I was told by the inhabitants that within the walls hyenas never attack people or livestock. But why are they welcomed here, when in other parts of the planet they are hunted? The people of Harar believe that every time a hyena laughs, it devours a bad spirit».

The trip to India of Devas. In Jaipur, he met a family who fed monkeys every morning for more than forty years. «When the oldest woman in the family died, the family gathered around her. In Jaipur, it almost never rains, on the ceiling of the house there is a hole from where the light comes in. At two o’clock in the morning, the alpha male of the herd entered the hut and touched the woman’s hand and ran away. Looking up there were other monkeys watching. I wondered how it was possible. The family told me that there was a spiritual connection between the monkeys and the woman. He fed them for years and that created a bond. Hindus associate these primates with the ape god Hanuman and worship them. The experience in India was how generous Indians are to the wildlife that lives in their cities. The reward for them is to be surrounded by animals».

Fredi Devas has a clear idea of how to give space to animals in our cities: we need to take a step back. Go back to nature, avoid the use of cars, favoring alternative mobility. In the UK, foxes have the same chance of survival in both the city and the countryside. «The main cause of their death in the city is cars », explains Devas. «It would be enough to limit their use to make their lives easier». You cannot just think about air or water pollution: artificial light confuses animals and plants. The invention of the incandescence light bulb 140 years ago changed our night skies forever, especially in metropolises. For many animals, artificial light creates confusion. In New York, a bright screen confuses the migratory birds that cross Manhattan every year; they are confused by its light and crash into it. Every morning the garbage collectors have to clean the dead birds that have fallen at its base.

Moths have evolved to fly to a distant light source: the moon. That is why they often find themselves circling the streetlights. Fredi Devas says: «There is one animal that can exploit the confusion of these insects: the Gecko Tokay, found mainly in Southeast Asia. Hong Kong has one of the brightest night skies in the world. Since the Tokay gecko is a lizard that lives after dark, it is hard to imagine that its eyes can cope with such intense light, but from their vertical slit pupils, only a small amount of light is let in when it is under a light bulb and opens in the dark. The other feature that makes Tokay geckos so well adaptable to the urban environment is their phenomenal grip. Each paw is coated with half a million microscopic hairs, so small that it forms a molecular bond with the surface on which they walk, almost like an atomic-scale Velcro. After evolving to walk on wet leaves in the rainforest, their feet adapted well to walking on metal and glass, making Hong Kong streetlights an ideal place to eat».


Enrico Alleva is an Italian ethologist.
He has been president of the Società Italiana di Etologia since 2008.

Fredi Devas is a documentary filmmaker.
He’s the producer of the BBC documentary series Planet Earth II.
He spent four years learning about animals living in many of the world’s most urbanized areas.