Camels: a rainforest animal

They call them the ships of the desert. Without them, the evolution of the Silk Roads to transport goods throughout Central Asia and Arabia would not be viable.

Camels are the ideal animal to survive in extreme environments. Where food and water were scarce, the camel thrived. Despite their association with deserts and steppes, their story began in the most unexpected environment – a rainforest in North America.

In this article, we unravel the unknown story behind the birthplace of the camel. We explore its body evolution as this rover friend left home to go on a world tour.

A rainforest camel  

Vast rainforests extended around Central-North America, 45 million years ago. Among them lived a humpless mammal of the genus Protypus whose body didn’t exceed the size of a goat. It fed on forest plants and is the oldest ancestor of modern camels.

For 38 million years, it thrived isolated within the continent that was encircled by oceans. During that time, climate change shifted the dense forests into open grasslands. That led to the appearance of different genera and species of camels.

The Exodus. Camels becoming a world traveller

Seven million years ago Earth’s climate became colder, which triggered an ice age. Ice caps began expanding outside the poles, causing a drop in world sea levels. That facilitated the formation of a land bridge at the Bering Strait.

The environmental conditions and food restrictions in Central-North America pushed one genus of camels to travel north-west. Upon their migration, some populations exited the continent by crossing the passage connecting North America with the Asian deserts. Other groups moved further north towards the Canadian Arctic circle.

A few million years after, tectonic shifting created the Panama Strait that bridged North with South America. It gave another American genus of camels the opportunity to resettle southwards, high on mountains.

Camelids body transformation 

When camelids (different genera of camels) migrated into different environments, their bodies transformed to endure new conditions. That makes them one of the most adaptive mammals that walked on Earth.

The migration process described below happened slowly over thousands of years. 

Moving westwards into the deserts  

Upon moving through the Bering land bridge towards the Eurasian steppes, genus Paracamelus had to adjust to the freezing, low-in-nutrition climate. It evolved two-humps of fat on its back acting as an energy source when food was scarce. Additionally, its skin thickened to inflate heat insolation.

It became the two-humped Bactrian camel. A population of them settled in the steppes and cold deserts of central Asia.

Some groups continued moving further southwest. Upon setting foot in the hot climates of Arabia where water scarcity was fatal, the camel gradually lost one of its two humps. By doing so, the surface area of its body exposed to the desert sun was reduced, thus the loss of water was minimized. Simultaneously, the area of their feet outspread to enhance the efficiency of walking on sandy ground.

The single-hump dromedary came to dominate the deserts of Arabia and the postcards with Egypt’s pyramids.

Migrating southwards over the mountains

During the southward migration of the North-American genus Hemiauchenia and the crossing of the Panama strait, it inhabited the mountainous, arid terrain of the Andes. This time instead of humps and thick skin, it developed fluff. It became the progenitor of wild guanacos and vicunas. Upon domestication by humans 7-9 thousand years ago, they became llamas and alpacas.

Twenty thousand years ago, the world moved into its most recent ice age. Homo sapiens moved from Asia to North America in the opposite direction camels did. The combination of hunting by humans and the harsh climate conditions drove the North American camel population that never left its birthplace into extinction.

Sum up

Camels left their rainforest-home, never to return. During their journey, they evolved their bodies and became the ultimate survivor in extreme environments. Eventually, escaping their motherland proved fundamental for the survival of the Camelid family. All species that never left North America, were led into extinction.

Extras 

• Camels can lose 25% of their weight, to survive starving conditions. Most mammals die after a 15% loss of body mass.  

• Camels and Alpacas share 83% of the same genome.  

• Each hump weights around 35kg.  

• The megacamel species had a height of 3,5 meters