SCIENCE Photos of Endangered and Vulnerable Species from Around the Globe Photo contest contestants capture rare images of threatened animals April 17, 2013 / Scientists estimate the population of Galápagos sea lions has declined roughly 50 percent since 1978. According to the International Union for Conservation of Nature (IUCN), introduced species such as feral dogs carry diseases that Galápagos sea lions are particularly susceptible to. Sea lions are also vulnerable to fluctuations in ocean currents due to climate change, which directly impacts their food source. Status: Endangered Photo by Melissa Estes (Fort Myers, FL); Photographed May 2011 / Orangutan numbers have declined rapidly since the middle of the 20th century because of human activities, including hunting, unsustainable and often illegal logging, mining and deforestation for agriculture. Catastrophic forest fires in Kalimantan in 1997 and 1998 also reportedly killed up to 8,000 orangutans. Status: Endangered Photo by Cheng Shun Ling (Singapore, Republic of Singapore); Photographed October 2010 / The WWF reports that the major threats to the survival of wild dogs include accidental and targeted killings by humans, viral diseases like rabies and distemper, habitat loss and competition with larger predators like lions. Conflicts occur when wild dogs come in contact with people whose livelihoods rest largely on livestock and agriculture, which shrink the animals' hunting grounds. Status: Endangered Photo by Daniel Cejudo (Santa Cruz de Tenerife, Canary Islands); Photographed October 2011 / Beluga whales return to the same estuaries each year which make specific populations vulnerable to overhunting. According to the WWF, climate change poses another threat as Belugas relying on sea ice to shield them from predators like orcas. Status: Near Threatened Photo by Lucinda Rhodes (Flint, MI); Photographed January 2007 / A now-outlawed fur trade caused a sharp decline in rock-wallabies. But according to the WWF, the species is still threatened by removal of native vegetation in their habitats, which forces the wallabies to compete for food with other animals. Status: Near Threatened Photo by Paul Huntley (North Sydney, Australia); Photographed August 2011 / The red-fronted lemur inhabits a long stretch of western Madagascar’s dry forest, as well as a much smaller portion of southeast Madagascar rainforest. According to estimates, the lemur's population has declined 20 to 25 percent over the last 24 years due to habitat loss and overhunting. Status: Near Threatened Photo by Carol Smith-Nichols (Bethlehem, PA); Photographed June 2012 / The spiny chuckwalla lives on islands in the northwestern Gulf of California. Chuckwallas resemble poisonous Gila monsters, which means the former is sometimes mistakenly killed by humans. Status: Near Threatened Photo by Scott Trageser (Tucson, AZ); Photographed May 2012 / The cheetah, the world's fastest land animal, has disappeared from huge portions of its historical range. Scientists believe there are now roughly only 7,500 adult animals in the wild. The decline is primarily due to habitat loss and the killing of cheetahs that are believed to be threats to livestock. Status: Vulnerable Photo by Scott Belt (Morris, IL); Photographed July 2012 / Bluefin tuna populations are declining because of overfishing and illegal fishing in the Atlantic, Pacific and Southern oceans. According to the WWF, their use as an ingredient in sushi creates a large demand. Status: Endangered Photo by Keith Ellenbogen (Newton, MA); Photographed June 2008 / The red panda's range includes Nepal, India, Bhutan, Myanmar and southern China. The current population is estimated at less than 10,000 mature adults. Habitat loss is considered the biggest threat to the species, but red pandas are also accidentally killed in snares set for animals such as deer and wild pigs. Status: Vulnerable Photo by Tracy Zams (Cherry Hill, NJ); April 2012 / Habitat destruction and hunting pose the greatest threats to the brown-headed spider monkey’s survival. Spider monkeys prefer undisturbed, mature forests and therefore are vulnerable to forest fragmentation. Status: Critically Endangered Photo by Liz Andrews (San Francisco, CA); July 2011 / The black rhinos' horns make the animals lucrative targets for illegal traders. Rhino horns are highly prized commodities in Asia where they are used both for ornamentation and traditional medicine. Between 1970 and 1992, 96 percent of the remaining black rhino population in Africa was killed, according to the WWF. In 2010, 333 rhinos were killed in South Africa for their horns—almost one every day. Status: Critically Endangered Photo by Lawrence Smith (Mission Viejo, CA); Photographed March 2011 / Historically, the jaguar, the largest cat in the Americas, ranged from the southwestern U.S. to the Rio Negro in Argentina. Today, the majority of the jaguar population, roughly 88 percent, is confined to the Amazon. Hunting and habitat loss due to deforestation threaten current jaguar populations. Status: Near Threatened Photo by Ben Shkolnik (Jerusalem, Israel); Photographed February 2007 / Whale sharks, the world's largest living chondrichthyan, can grow up to 40 feet in length. Whale sharks are targeted for their meat, fins and oil and may become tangled in fishing gear designed to catch other fish. Status: Vulnerable Photo by Aaron Fink (Atlanta, GA); Photographed October 2010 / With only roughly 1,600 giant pandas left in the wild, according to a 2004 survey from the the WWF, the species is quickly disappearing. The panda's primary habitat, China’s Yangtze Basin region, is the geographic and economic heart of a country in an economic boom. Roads and railroads crisscross forests, making it harder for panda populations to expand and mate. Deforestation also reduces pandas’ access to bamboo, their main food source. Status: Endangered Photo by Barbara Williams (Owings Mills, MD); Photographed February 2008 / Bonobos face an increasingly troubled existence; only part of their habitat is protected, and due to a growing human population and increases in agricultural and logging, they are losing their homes. Humans also hunt them for food and use them in traditional medicine, says the WWF. Status: Endangered Photo by Graham McGeorge (Jacksonville, FL); Photographed October 2012 / Expanding human populations in India have pushed tigers into small, isolated habitats—and resulted in some unusual behaviors. Sangeeta Dhanuka, Mumbai / The loss of sea ice habitat due to climate change is the biggest threat to polar bears today. Polar bears rely on the sea ice as a way to access seals, their primary food source. The changing climate also forces polar bears to spend longer periods on land rather than in open water, leading to increased contact with Arctic communities, according to the WWF. Such interactions sometimes prove deadly for both humans and bears. Status: Vulnerable Photo by Claire Waring (Kettering, UK); Photographed June 2012 / The mountain gorilla is found only in two isolated populations - one in Bwindi Impenetrable National Park in Uganda and one in the Virunga Volcanoes region that overlaps Rowanda, Uganda and the Democratic Republic of Congo. Scientists estimate the eastern gorilla population, of which the mountain gorilla is a subspecies, will suffer a decline of over 50 percent over the course of three generations. Status: Endangered Photo by Gonçalo Barriga (Paço de Arcos, Portugal); Photographed September 2012 / African elephant populations, which numbered roughly 3 to 5 million in the last century, have been severely reduced because of hunting, according to the WWF. A growing demand for ivory in Asia has led to a surge in poaching in Africa, making a population that once showed promising signs of recovery at risk once more. Status: Vulnerable Photo by Jacqueline Deely (San Jose, CA); Photographed September 2011 / Population declines have resulted from the overharvesting of eggs and adult females from nesting beaches. The animals' feeding grounds, such as sea grass beds, are also at risk from onshore coastal development, and green sea turtles are often accidentally killed as fishing "bycatch." Status: Endangered Photo by Jesse Farrar (Kapolei, HI); Photographed October 2007 Get the latest Science stories in your inbox.