The Earth Story

The Ancient Amazon was once a thriving metropolis

When one thinks of the lush Amazon rainforest, an ancient flourishing metropolis probably isn’t the first thing that comes to mind. The Amazon is the Earth’s largest rainforest, spanning an area of 6.7 million square kilometers across nine countries, and is home to one-tenth of world’s known species. Trying to survive the Amazon, let alone attempting to build a functioning society, is a pretty grim task, and scientists believed that the Amazon had always been an untouched wilderness before the modern era of deforestation. Yet archaeologists have found evidence that complex societies had existed in the Amazon for thousands of years, and that the wilds of the Amazon only reclaimed these settlements in the past few hundred years.

Researchers studied plant and soil samples, and simulated models of the Amazonian landscape to estimate population sizes and language distributions. They found that the Amazon’s “dark earths” — organic-rich soils that formed from the remains of fires, farming, and human waste — first appeared in the Amazon 6,000 years ago. By the end of the 15th century, the dark earths had expanded enough to support populations of over 8 million. But when the European colonists arrived in the Americas with plans of conquest, they also brought along a host of diseases that killed more than 50 percent of the Native American communities. The Amazonian peoples were eventually decimated, allowing Mother Nature to consume the vestiges of their civilizations.

Interestingly enough, the Amazonian peoples had successfully built their societies without clearing areas of forest for crop pastures. What researchers hope to figure out next is something that we are still trying to learn today — how the Native Amazonians were able to build complex societies without wiping out their rainforest environment.

-DC

Photo credit: http://bit.ly/1GShWhB

More reading: http://bit.ly/1U1fIWF http://bit.ly/1S5fdgT

How to survive the Amazon: http://usat.ly/1hPOz9l

The Social Side of Male African Elephants The social relationships between female elephants is relatively well established; documentaries and TV shows love to talk about the matrilineal society that elephants form. But new research is emerging about the role male elephants play in that society, and it's much more social than previously thought. The aggressive, loner persona of the male African elephant's has roots in the hormonally driven mating urge. This mating state, called "musth", is a basic way that male elephants can advertise to females that they are healthy and will produce strong, healthy babies. But musth is also responsible for some outstanding fights between males which can occasionally end in death - and overturned tourist vehicles. Musth first kicks when the male is about 30 years old and is relatively brief to begin with, perhaps lasting a few days or weeks. Older males, however, are in musth for months. In addition, scientists once thought young males around the age of 18 were kicked out of their original family groups because females were often seen driving the males away. It is now understood that these males drifted from their original family groups, tried to join another family group but face hostility because they are strangers. In fact, 80 percent of a male's time before the age of 25 is spent with family groups, but not necessarily with their original family group. During this time a dominant hierarchy based mostly on size is established between the males. Musth can occasionally blur that line, but for the most part every male elephant has his place. Interestingly, scientists have discovered that this hierarchy is fairly flexible in times of plenty, but often becomes very strict in times of scarcity, which might ensure order in family groups, particularly where water is concerned. Even more amazing, scientists are realizing just how important socializing can be between males. For example, young males learn about mating and male society by watching older males. While play sparring often occurs between males who are the same age and size, older males will sometimes join in the fun. Hilariously, they will often get down on their knees when fighting younger males. In addition, groups of males often touch each other, particularly at watering holes, to establish bonds. They do this by throwing their trunks up on each other's heads or covering each other's backs with their ears. It's kind of like friends at a bar slapping each other's backs. This new understanding of male elephant's social life is shedding light on just how damaging poaching can be to elephant society. Most poachers hunt older male elephants; the older an elephant the greater the tusk. But these older male elephants often teach social norms to the younger elephants; a loss of older elephants means a loss of an elder's wisdom. Further reading: http://www.bbc.com/earth/story/20141101-male-elephants-have-a-sweet-side?ocid=fbert Photo courtesy of: Dan L. Perlman http://www.ecolibrary.org/page/DP173 -Colter