Dwindling species are eventually recategorized as Critically Endangered (CN) or even Extinct in the Wild (EW). You probably know what that means: a species is extinct when individuals of that species no longer exist. Once a species is extinct, it is extinct forever.
Igor the Gorilla
This splendid and majestic individual named Igor lived at the Antwerp Zoo until his death in 1995. Today, he is one of the star attractions in an exhibit called “250 Years of Natural Sciences” at the Museum of Natural Sciences (Museum voor Natuurwetenschappen) in Brussels, Belgium, and his skeleton can be viewed in the “Gallery of Humankind.”
By Ted ThaiLIFE Photo Collection
Previously known as the eastern lowland gorilla, this is the largest of the gorilla subspecies. Until the mid-1900s, the Grauer’s gorilla population was estimated at 17,000 individuals.
Gorilla Family (1971) by Nina LeenLIFE Photo Collection
Latest surveys suggest that those numbers have dropped to fewer than 4,000 due to deforestation and poaching. As a result, this species is on the IUCNs Endangered list.
The Threat of Extinction
Imagine that an individual is the last one of its kind. When it dies, the whole species is gone. Identifying the moment when a species becomes extinct is impossible unless the individual is in captivity, so this determination is usually made retrospectively.
Here’s a staggering statistic: more than 99% of all species—that’s over five billion species—that ever lived on this planet are now extinct. So, is extinction a biological tragedy, or it is a normal and unavoidable part of life on Earth?
Several factors make the Galápagos tortoise particularly prone to decline. In the 16th century, their numbers topped 250,000. By the 1970s, their numbers had dwindled to 3000. A conservation success story has brought them back to nearly 20,000 today.
The Australian lungfish is one of the oldest vertebrates on Earth. It lives in the slow rivers of Queensland. Threatened by the loss of its breeding grounds and the introduction of translocated tilapia, the species is classified as Vulnerable (VU).
The Thylacine or Tasmanian Tiger
Tasmanian ranchers mistakenly thought this carnivorous marsupial threatened their sheep, and so thylacines were systematically eliminated in the late 1800s and early 1900s. The very last one died in captivity on September 7, 1936.
The very last one died in captivity on September 7, 1936. In Australia, September 7 is now National Threatened Species Day.
Reunion Island Dodo (1907) by Natural History MuseumThe Natural History Museum
This extinct flightless bird, native to Mauritius, was about three feet tall and may have weighed twenty pounds, but all we know of this victim of human hunting is from art, fossils, and writings from the 17th century.
Sound the Arctic Alarm
Danger, danger! The Arctic is warming faster than the rest of the planet, and scientists predict that by 2030, the Arctic Ocean may be entirely ice-free in the summer months. Many polar species depend on the ice to survive.
Overfishing, mining, oil and gas development, shipping, and higher average yearly temperatures brought about by global warming threaten their survival.
Currently classified as Vulnerable by the IUCN, polar bears have become a powerful symbol of species threatened by human activity.
Polar Bear-Polar Bear, Canada by Co RentmeesterLIFE Photo Collection
Large carnivores that sit at the top of their food chains are good indicators of the health of their ecosystems, so conservationists pay close attention to the population of polar bears.
Elephant in the Rotunda
In 1955, Josef J. Fénykövi killed this African elephant near his 1000-acre ranch in Angola in southwestern Africa. It was the largest elephant ever shot.
The big game hunter gifted it to the National Museum of Natural History in Washington, D.C., to be prepared for display by its taxidermy staff. Today, it stands in a place of honor in the central rotunda of this museum for everyone to admire.
African Bush Elephants
In the early part of the 20th century, there may have been as many as 3.5 million African elephants. Today, there are about 470,000. They are threatened by poachers who supply the illegal ivory trade and by habitat loss due to deforestation.
Sometimes, the accidental or careless introduction of a non-native plant or animals can threaten the survival of a species.
Mesquite (1952-06) by John DominisLIFE Photo Collection
Take mesquite, for example. When it was introduced into Ethiopia in the 1990s, it began to endanger the grasses that native animals depended on, and it is now considered one of the world’s most problematic invasive species.
Zoo ZebraLIFE Photo Collection
These beautiful animals once inhabited the plains of Somalia, Ethiopia, and Kenya, but their range has shrunk. Due to overgrazing, competition for water, and hunting, they now have a low survival rate and are currently Endangered (EN) on the IUCN Red List.
The Great Barrier Reef
This 133,000-square-mile wonder off the coast of Queensland, Australia, contains the world’s largest single structure made by living organisms, with 400 kinds of coral, 1,500 species of fish, and 4,000 types of mollusk.
It is the habitat of several threatened species, such as the dugong (sea cow) and the large green turtle. The GBR is so vast that it can be seen from outer space! A large part of the reef is protected by the GBR Marine Park, which helps limit the impact of the human footprint.
Coral Reefs in Danger
About one-quarter of the coral reefs in the world are considered damaged beyond repair and another half are under serious threat. Major threats include destructive fishing practices, overfishing, careless tourism, pollution, erosion, mining, and global warming.