10 Animals That Could Disappear Forever [PHOTOS]

On Monday, 8,000 scientists from the IUCN Species Survival Commission released a list of what they're calling the 100 most threatened species. Some of the animals on the list are victims of poachers, like the Javan rhino, which is pursued for the supposedly medicinal uses of its horn. Many are disappearing as humans encroach on their habitat.

So without further ado, here are 10 of the 100 animals on IUCN's most threatened list. See them while they still exist!

Credit: Bill Hatcher via Edge of Existence

Pygmy three-toed sloth (Bradypus pygmaeus): Found only on the islands of Bocas del Toro off the coast of Panama. There are probably less than 500 of these left, according to IUCN.

Credit: Ciro Albano.

Araripe manakin (Antilophia bokermanni): This striking bird, like the pygmy sloth, has a very small range, limited to a tiny region in the uplands of Brazil. Its population is estimated at less than 800 birds.

Credit: Rahul Sachdev

Great Indian bustard (Ardeotis nigriceps): This bird once flourished throughout India and Pakistan, but is now down to fewer than 250 birds, according to a 2008 estimate. Attempts to breed the bustard in captivity have failed.

Credit: Luciano Candisani

Santa Catarina's guinea pig (Cavia intermedia): This guinea pig lives on the Brazilian island of Moleques do Sul, and is limited to a range of only 4 hectares (just above one-hundredth of a square mile).

A museum specimen of a young Javan rhinoceros. Credit: Peter Maas.

Javan rhinoceros (Rhinoceros sondaicus): Around 40-60 rhinos live in a National Park in Indonesia; another tiny population, possibly around six individuals, lives in Vietnam. Rhinos have been aggressively hunted for their horns, which are prized trophies and a sought-after ingredient in some traditional Chinese medicines.

Credit: Atherton de Villers

Table Mountain ghost frog (Heleophyrne rosei): This South African frog species has existed for 160 million years, but is now being crowded out by invasive plants and human intrusion.

Credit: Erik Baard

Geometric tortoise (Psammobates geometricus): Another South African resident, this tortoise was thought to have died out in the 1960s, but survivors were discovered in1972. There are only about 2000 to 3000 of these left today.

Credit: Lizzie Noble Fundacion ProAves

Red-crested Tree Rat (Santamartamys rufodorsalis): This rodent also seemed to rise from the dead in 2011, when it was spotted in Colombia for the first time since 1898.

Credit: Ian Vernon Tim Hounsome Durrell Wildlife Conservation Trust

Durrell's vontsira (Salanoia durrelli): A close relative of the mongoose, this little carnivore lives in marshes in Madagascar. Recently it has been threatened by the construction of rice fields and competition from black rats and the Indian civet.

Credit: Norihiro Kawauchi

Muennink's Spiny Rat (Tokudaia muenninki): This rodent lives in the forests on Japan's Okinawa Island, with a range of less than 3 square kilometers (1.2 square miles).