10 surreal cities inhabited by animals
Before 2007, more people lived in rural areas than in cities. Since then, people have become more concentrated geographically and many cities have grown in size as people flocked to them. But some species have lived close together in this way for long periods of time for the same reasons as humans, such as being close to the resources they need, for defense, and to cooperate or socialize with others.
Although trained architects and urban planners are lacking, these animal cities are often impressive. Some are very complex and built over generations; others make clever use of their environment, and the populations of some of them dwarf those of the largest human cities. In no particular order, here are ten of the most amazing animal cities.
Related: 10 South American animals that get a bad rap
10 Eel city
Eel City leaves no mystery as to what slick citizens can be found there, but what's strange is why there aren't other places like it. The volcano is found about 2,000 feet (609 meters) below the South Pacific Ocean, around the summit of a recently formed volcano called Nafanua, just off the coast of American Samoa. Scientists on an expedition to view the volcano in 2005 were surprised to suddenly see hundreds – perhaps even thousands – of eels running in and out of the crevices.
Some scientists had experience exploring hydrothermal vents under the sea and said they had never seen or heard anything like the eel city. Small eels are often seen in the deep sea, but it is unusual for such a large group to be found together. And eels are not known to eat microbial mats, the only possible food source the scientists could see around the volcano.[1]
9 Octlantis
A population of fifteen may not sound like a real city, but if those fifteen are “gloomy” octopuses who were thought to be antisocial loners, that's actually quite remarkable. The researchers who found the Australian site named it Octlantis, not to be confused with the nearby city of Octopolis they found a few years earlier. Although the residents of Octlantis no longer lived alone, they were still quite antisocial. Scientists watched them fight and even drive each other out of their hiding places.
It seems like 15 is a crowd, but two is still company, and the scientists also saw the octopuses mating and communicating. It's unclear what made the octopuses work together in the first place. They could have done this for defense, which would be an example of the creatures' considerable intelligence, or it could simply be that the area has plenty of food but not much shelter.[2]
8 Underground ant city
In 2012, a sophisticated but mysteriously abandoned underground city was unearthed by scientists. The population once numbered millions and was ruled by a queen, with each citizen fulfilling a specific role in society, from soldier to sanitation worker. They left behind an extensive and complex network of highways, tunnels, waste pits and gardens. Visitors wanting to see this historical wonder should head to Brazil, but will have difficulty getting in. Why?
Because it wasn't built by humans, but by tiny leafcutter ants. For creatures of their size, the project has a scale comparable to that of the Great Wall of China. It covers an area of 500 square feet (46.5 square meters) and descends 26 feet (7.9 meters) below the ground surface. Although their colonies are usually much smaller and can even be as small as an acorn, the work probably didn't put too much strain on the ants, which are super strong and can lift up to 50 times their own body weight.[3]
7 Ancient termite megalopolis
As impressive as an ant-built city on the scale of the Great Wall is, it pales in comparison to the work of another small insect species. It is believed that termites began working on the 200-million-mound megalopolis in northeastern Brazil about 4,000 years ago. Despite this long history, the site is still inhabited and still under construction. The network of tunnels beneath the mound-shaped mounds, which are up to 3 meters high, covers an area about the size of Britain, and the amount of soil the tiny mites have moved is the same as that of about 4,000 Great Pyramids of Giza.
Surprisingly, the area is difficult to see from the ground as it is surrounded by a semi-arid forest. However, it can be seen via satellite. The forest is the reason the termites bothered to dig the tunnel complex in the first place; they eat the dead leaves, and the tunnels help them emerge and escape safely when they need food.[4]
6 The Valley of the Giants
Entering a large, deep cave in the middle of a forest, with deep grooves in the walls almost certainly carved by the claws of some colossal creature, is not a job for the faint of heart. Fortunately for the paleontologists who discovered and explored a complex of six such caves in Minas Gerais, Brazil, the giant animals that inhabited them became extinct about 10,000 years ago. The caves are actually paleo-caves, meaning they were dug by animals, and the most likely culprits seem to be giant prehistoric ground sloths and armadillos.
Although some species of ground sloths can grow up to 6 meters tall when standing, the size of the burrows (up to 40 meters deep and 4 meters high) indicates that they were dug by a colony rather than an individual. This is supported by a pair of small, smooth cavities dug into the wall of the last chamber of each burrow. They may have been individual resting places for the residents.[5]
5 Sky cities
Surprisingly, a 'sociable weaver' is not in fact a member of a crochet club, but an unusual bird species found in South Africa and Namibia. It is said that birds of a feather flock together, and this is certainly true of gregarious weavers, who build enormous nests that resemble thatched roofs high in the treetops so they can live in large groups. One nest can consist of up to 95 separate rooms where families of the birds can make their home.
The first person to write about them, in the late 18th century, described their nesting style as a “sky city” and saw one so large that he suspected as many as 800 to 1,000 birds lived in it. They are also truly social, as they even allow other bird species, such as the pygmy falcon, to use their nests for shelter and reproduction.[6]
4 King Penguin City
St. Andrew's Bay, on the icy island of South Georgia near Antarctica, is home to one of the world's largest penguin colonies. About 400,000 king penguins gather on the island, which is an astonishing number considering that whalers were forced to abandon the island in the past century after driving the wildlife there to extinction. Even more impressive is that the adult penguins, who leave for up to five months at a time to catch food, can actually fight their way through the crowded beach to find their own young.
Although this penguin 'city' contains no shelters or tunnels, it is impressively organized considering its lack of leadership. Molting penguins are brought together, as are the mischievous young chicks while their parents are away. Penguins needing to wash and bathe gather around natural pools in the bay, and long, less densely packed columns lead like highways to the sea.[7]
3 Prairie dog town
Nitpickers might point out that the groups in which black-tailed prairie dogs live are called “towns” and not “towns,” but the population of the largest recorded prairie dog town was far greater than that of any human city. In fact, it is much larger than the population of most countries. It was discovered in Texas in the early 20th century and covered 250 x 100 miles (402 x 161 kilometers) with a population of 400 million prairie dogs.
That meant that about 50% of the rodents estimated to be living in Texas at the time lived in that one giant city. The 64,750 square kilometer city has since been broken up by people who settled the area and developed the land. This has caused the prairie dog population in Texas to decline by more than 99% since that time. However, it is now relatively stable at around eight million.[8]
2 Monkey city
Something many animal cities have in common is their distance from human settlements. However, abandoned buildings can sometimes serve the needs of animal colonies, and many do not remain empty for long. For example, the beautiful, ancient ruins of the ancient city of Polonnaruwa, Sri Lanka, are now home to approximately 4,000 macaques. And this strange animal city even conducted a census of sorts, as the site's monkeys were part of a major Smithsonian Institute study between 1968 and 2008.
Everyone who lived there was given their own name, and some were named after famous people and local leaders. They also gained a small amount of fame by starring in documentaries such as the Animal Planet film Dark days in Monkey City. Discovery Channel and the BBC also made programs about them.[9]
1 The polar bear capital of the world
Some brave species live in cities not of their own design or of nature. Instead, they reside in human cities, and not just abandoned ones. There is nothing unusual about the coexistence of rats, foxes and pigeons with city dwellers around the world. But in Churchill, Canada, residents and visitors must spend a few months each year coexisting with the world's largest land carnivore, the polar bear.
In winter, when temperatures drop and polar bears make their way to Hudson Bay to hunt seals, hundreds of them flock to the Churchill area. Suddenly it becomes the 'Polar Bear Capital of the World'. Some effort is made to deter the bears and guide them around the settlement, but it is still not uncommon for some to slip through. Fortunately, they are often frightened by encounters with humans, and fatalities are rare.[10]