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On or around October 31, 2011, the human population will reach the 7 billion mark, according to projections by the United Nations Population Division. Over the years, as our numbers have increased, the populations of the Earth's other inhabitants has steadily decreased; many species have even gone extinct. Habitat loss, pollution, global warming, overfishing and overhunting all of which are connected to the human population explosion are some of the prime reasons for the current and future loss of species.
Some biologists believe that with the current rate of extinction, the Earth will experience its sixth mass extinction, where 75 percent of the planet's species disappear in a geologically short period of time, within the next 300 to 2,000 years.
Here are 10 endangered species that the growing population and expanding range of humans will likely kill off long before the mass extinction event hits.
The Black-Footed FerretSlide 2 of 21
The Black-Footed Ferret
The black-footed ferret (Mustela nigripes), North America's only native ferret, has long been one of the world's most endangered species. In the late 1900s, there was a national effort in the United States to rid prairies and grasslands of prairie dogs, a type of burrowing rodent that can reduce crop yields and create hazardous holes in the ground. However, these efforts inadvertently caused a dramatic decline in the population of the black-footed ferret, whose diet is 90 percent prairie dog. Human development, which cut the ferret's grassland habitat to less than 2 percent of its original size, also had a major impact on the animal's population, as did disease.
In 1986, scientists believed that there were only 18 black-footed ferrets left in the wild, but breeding programs have helped the ferret's population steadily climb to around 1,000 since then. The black-footed ferret still remains on the brink of extinction and its survival depends largely on the preservation of its now fractured habitat.Slide 3 of 21
Mekong Giant CatfishSlide 4 of 21
Mekong Giant Catfish
With some individuals stretching passed 10 feet long and weighing more than 600 pounds, the Mekong giant catfish (Pangasianodon gigas) holds the Guinness World Record for the largest freshwater fish ever caught. But while it may be physically large, its population is anything but: the number of wild Mekong giant catfish has declined by around 90 percent in the last decade and some experts believe that there are fewer than 300 of the behemoths left. [Why Do Dead Fish Float? ]
Once spanning almost the entire Mekong River, the Mekong giant catfish is now only found in the lower half of the river, in Cambodia, Laos, Thailand and Vietnam. Overfishing has played a major role in the fish's decline, but alterations to the fish's habitat including the construction of dams that block migration routes, and the destruction of spawning and breeding grounds are also to blame. River development projects, along with current ineffective bans on fishing, may soon spell the doom of this record-holder. [Can a Goldfish Really Grow to 30 Pounds? ]Slide 5 of 21
VaquitaSlide 6 of 21
With a population of fewer than 300 individuals, the vaquita porpoise (Phocoena sinusis) is the world's smallest and most endangered cetacean, a group of marine mammals that includes whales, dolphins and porpoises. The vaquita, which means "little cow" in Spanish, also has the most limited habitat of all cetaceans it is only found in the northern extremes of the Gulf of California.
Until recently, the greatest threat to the vaquita has been gillnets set for mackerel and sharks. In 2000, Mexico's International Committee for the Recovery of the Vaquita estimated that the 1,300 gillnets were killing between 39 and 84 of the porpoises each year. Recently, the Mexican government and the tourism and fishing industries cut the number of gillnets in the gulf by 80 percent, drastically reducing the number of vaquita killed each year as bycatch.
However, even if the number of net-caught vaquitas is reduced to zero, other dangers, such as chlorinated pesticides, still pose a major threat to the survival of this rare marine mammal. The vaquita will likely follow the path of another small cetacean, the baiji, which researchers declared extinct in 2006.Slide 7 of 21
Hine's Emerald DragonflySlide 8 of 21