Life on Earth is dynamic, with new species emerging and others disappearing. Human activities have significantly accelerated the rate at which species vanish. Understanding these disappearances offers insights into the delicate balance of ecosystems and the profound impact of human presence.
The Nature of Extinction
Extinction is the complete disappearance of a species from Earth, occurring when its last individual dies. This natural process is part of evolution, where species adapt or perish as environments change over geological timescales.
Historically, species went extinct at a slow “background rate,” averaging one to five per year. The current rate is 100 to 1,000 times higher, an accelerated loss often called the “Sixth Mass Extinction,” largely driven by human influence.
Primary drivers of this rapid decline include habitat loss and degradation, overexploitation (such as excessive hunting, fishing, or logging), and climate change. The introduction of invasive species can outcompete native organisms or introduce new diseases.
Notable Extinct Species
The Dodo, a flightless bird native to Mauritius, vanished around the late 17th century. This large pigeon relative was accustomed to an environment without predators. Its extinction was driven by human hunting, habitat destruction, and introduced species like pigs and rats that consumed its eggs.
The Passenger Pigeon, once North America’s most abundant bird, disappeared by 1914 with the death of Martha. These birds formed immense flocks that darkened skies. Their extinction resulted from relentless commercial hunting for meat and habitat destruction through widespread deforestation.
The Thylacine, or Tasmanian Tiger, was a carnivorous marsupial native to Tasmania. It had a wolf-like body with distinctive stripes; the last known individual died in captivity in 1936. Its decline was due to intensive hunting (driven by livestock bounties), habitat fragmentation, and disease.
Steller’s Sea Cow, a large, herbivorous marine mammal, inhabited the cold waters of the Bering Sea. These gentle giants fed on kelp in coastal areas. Discovered in 1741, it was hunted to extinction within 30 years by 1768, primarily by sailors and fur traders seeking its meat, fat, and hide.
The Quagga, a zebra subspecies native to South Africa, had stripes only on its head, neck, and front, fading into a plain brown rear. The last known individual died in 1883 in an Amsterdam zoo. Its extinction was a direct consequence of extensive hunting by European settlers for its meat and hide, and competition for grazing land with domestic livestock.
The Baiji Dolphin, a freshwater dolphin endemic to China’s Yangtze River, was declared functionally extinct in 2006 after surveys failed to find any living individuals. Its disappearance was caused by severe habitat degradation, overfishing, entanglement in fishing gear, and vessel collisions within the heavily industrialized river.
The Golden Toad, a brightly colored amphibian, was once abundant in Costa Rica’s cloud forests. Its last confirmed sighting occurred in 1989, and it is now considered extinct. Its decline is largely attributed to climate change, which altered its habitat’s moisture balance, and the emergence of the chytrid fungus, a deadly amphibian pathogen.
The Pyrenean Ibex was a wild goat subspecies native to the Pyrenees mountains of France and Spain. This animal had large, curved horns and was well-adapted to rugged terrain. The last naturally occurring individual died in 2000, primarily due to relentless hunting pressures, disease, and competition from domestic livestock.
The Great Auk, a large, flightless seabird, was found in the North Atlantic. It was an adept swimmer but clumsy on land. The last pair was killed in 1844 on Eldey Island, Iceland. Its extinction was driven by extensive hunting for its meat, eggs, and feathers, particularly for stuffing mattresses.
The Carolina Parakeet, North America’s only native parrot, was once common across the eastern United States. The last known individual died in captivity in 1918. Its extinction was due to habitat loss from deforestation, hunting to protect crops, and capture for the pet trade.