Isthmus of Panama

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The Isthmus of Panama

The Isthmus of Panama (Spanish: Istmo de Panamá), also historically known as the Isthmus of Darien (Spanish: Istmo de Darién), is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country of Panama and the Panama Canal. Like many isthmuses, it is a location of great strategic value.

The isthmus formed around 2.8 million years ago.[1] This major geological event separated the Atlantic and Pacific Oceans and caused the creation of the Gulf Stream. This was first suggested in 1910 by North American paleontologist Henry Fairfield Osborn. He based the proposal on the fossil record of mammals in Central America.[2] This conclusion provided a foundation for Alfred Wegener when he proposed the theory of continental drift in 1912.[3]


Núñez de Balboa's travel route to the South Sea, 1513
An 1850 oil painting by Charles Christian Nahl, titled, The Isthmus of Panama on the height of the Chagres River

Vasco Núñez de Balboa heard of the South Sea from natives while sailing along the Caribbean coast. On 25 September 1513 he saw the Pacific. In 1519 the town of Panamá was founded near a small indigenous settlement on the Pacific coast. After the discovery of Peru, it developed into an important port of trade and became an administrative centre. In 1671 the Welsh pirate Henry Morgan crossed the Isthmus of Panamá from the Caribbean side and destroyed the city. The town was relocated some kilometers to the west at a small peninsula. The ruins of the old town, Panamá Viejo, are preserved and were declared a UNESCO World Heritage Site in 1997.

Silver and gold from the viceroyalty of Peru were transported overland across the isthmus by Spanish Silver Train to Porto Bello, where Spanish treasure fleets shipped them to Seville and Cádiz from 1707.

Lionel Wafer spent four years between 1680 and 1684 among the Cuna Indians.

Scotland tried to establish a settlement in 1698 through the Darien scheme.

The California Gold Rush, starting in 1849, brought a large increase in the transportation of people from the Atlantic to the Pacific. Steamships brought gold seekers from eastern US ports who trekked across the isthmus by foot, horse, and later rail. On the Pacific side, they boarded Pacific Mail Steamship Company vessels headed for San Francisco.

Ferdinand de Lesseps, the man behind the Suez Canal, started a Panama Canal Company in 1880 that went bankrupt in 1889 in a scandal.

In 1902–4, the United States forced Colombia to grant independence to the department of the isthmus, bought the remaining assets of the Panama Canal Company, and finished the canal in 1914.


The closure of the Isthmus led to allopatric speciation events of marine organisms isolated on each side (blue and green). Terrestrial species also migrated between the two continents upon the formation of a passable land bridge (the Great American Biotic Interchange.



Evidence also suggests that the creation of this land mass and the subsequent warm, wet weather over northern Europe resulted in the formation of a large Arctic ice cap and contributed to the current ice age. That warm currents can lead to glacier formation may seem counterintuitive, but heated air flowing over the warm Gulf Stream can hold more moisture. The result is increased precipitation that contributes to snow pack.

The formation of the Isthmus of Panama also played a major role in biodiversity on the planet. The bridge made it easier for animals and plants to migrate between the two continents. This event is known in paleontology as the Great American Interchange. For instance, in North America today, the opossum, armadillo, and porcupine all trace back to ancestors that came across the land bridge from South America. Likewise, bears, cats, dogs, horses, llamas, and raccoons all made the trek south across the isthmus.


As the connecting bridge between two vast land masses, the Panamanian biosphere is filled with overlapping fauna and flora from both North and South America. There are, for example, over 978[5] species of birds in the isthmus area. The tropical climate also encourages a myriad of large and brightly colored species, insects, amphibians, birds, fish, and reptiles. Divided along its length by a mountain range, the isthmus's weather is generally wet on the Atlantic (Caribbean) side but has a clearer division into wet and dry seasons on the Pacific side.

See also


  1. ^ Formation of the Isthmus of Panama
  2. ^
  3. ^
  4. ^ "North and South America Came Together Much Earlier Than Thought: Study". NBC News through Reuters. April 9, 2015. Retrieved April 9, 2015. 
  5. ^ The Birds of Panama A Field Guide by George R. Angehr and Robert Dean


  • A New Voyage and Description of the Isthmus of America (1695), by Lionel Wafer. Excerpt from the 1729 Knapton edition
  • Seager, R. (2006) 'The Source of Europe’s Mild Climate.', American Scientist, 94(4), pp. 334.

Coordinates: 8°40′N 80°0′W﻿ / ﻿8.667°N 80.000°W﻿ / 8.667; -80.000

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