This story is part of the pessimistic argument for the future of the planet in our special issue on Earth Day. Read the optimistic argument and the rest of our stories here.

Pandas and tigers may be the poster creatures for conservation, but thousands more threatened animals languish out of the spotlight. Most of them aren’t cuddly or charismatic, but they’re no less crucial to ecosystems. Of the 30,000 species documented as being at risk of extinction, 28 percent are reptiles—including six of the seven kinds of sea turtles. Birds are declining because of climate change, habitat loss, predation, and pesticides, with a whopping 2.9 billion fewer in North America than in 1970. Reversing the trend over the next half century requires focusing a lot more attention on these underappreciated rarities.

Gray crowned crane

(endangered)

The population of this endangered African crane has dropped from more than 100,000 wild individuals to some 30,000 in the past 35 years. Reaching heights of around three feet, the elegant bird has suffered from poaching for its meat and eggs, as well as from the destruction of the wetland habitat where it breeds and hunts. The crane pictured here is a captive animal at France’s Parc des Oiseaux.

View Images Koalas, photographed at the Australia Zoo in Beerwah, Queensland

Photograph by Joel Sartore, National Geogrphic Photo Ark

Koala

(vulnerable)

Widespread hunting in the 19th and 20th centuries took a toll on koala populations. Now the fuzzy marsupials, often mistakenly called koala bears, face new perils: climate change; highways that fragment habitats; and the sexually transmitted disease chlamydia, which has ravaged some groups with a 100 percent infection rate. Wildfires have become a particular threat. Koalas rarely descend from the eucalyptus trees whose leaves make up the bulk of their diet, so many have been unable to escape the unprecedented fires in eastern Australia. These young koalas, or joeys, snuggle together at the Australia Zoo in Beerwah, Queensland.

View Images Hawksbill turtle, photographed at the Australia Zoo Wildlife Hospital Photograph by Joel Sartore, National Geogrphic Photo Ark

Hawksbill turtle

(critically endangered)

Found in tropical and subtropical waters worldwide, hawksbill turtles are hunted for their eggs, meat, and beautiful shells, which are made into decorative tortoiseshell items. Fewer than 25,000 nesting females likely remain. Some conservationists have placed GPS tags on the 150-pound reptiles to gain insight into their mysterious underwater lives. The hawksbill above was photographed at the Australia Zoo Wildlife Hospital.

View Images Togo slippery frog, at a private collection in St. Augustine, Florida Photograph by Joel Sartore, National Geogrphic Photo Ark

Togo slippery frog

(critically endangered)

Of the 100 most genetically distinct and critically endangered animals in the world, the Togo slippery frog ranks 18th. It is as different from other amphibians as humans are from pigs—an avatar of biodiversity. Its lineage is ancient: It’s part of a family that goes back 70 million to 80 million years, to the time of the dinosaurs. And in its habitat on the border of Ghana and Togo, it’s roughly 240 individuals away from extinction. To live, the three-inch-long frog needs clean, fast-running water—which increasingly is polluted or siphoned off by humans. The frog needs forest habitat, which is being cleared out by logging for wood, hunting, fishing, and the expansion of farming and housing. And the edible species needs protection: Togo slippery frogs are still eaten today, with children hunting them after school. On all three counts, the species is the focus of advocacy by nonprofit group Herp Conservation Ghana.

View Images Northern white-cheeked gibbons, at the Gibbon Conservation Center in Santa Clarita, California Photograph by Joel Sartore, National Geogrphic Photo Ark

Northern white-cheeked gibbon

(critically endangered)

This long-armed, arboreal ape is native to the evergreen and semi-evergreen forests of China, Vietnam, and Laos. However, it hasn’t been spotted in China since 1990, sparking fears that it’s already gone extinct there. And throughout the gibbon’s range, the population is thought to have shrunk by 80 percent in the past 45 years. Predation, poaching, and deforestation are factors in the decline. Raptors snatch the apes from the forest canopy where they live; humans hunt the gibbons to eat, sell in the illegal pet trade, and use in traditional medicines. Much of the apes’ forest habitat has been razed by people seeking fuel, timber, and arable land.

View Images Sunda pangolin, at the Carnivore and Pangolin Conservation Center in Vietnam Photograph by Joel Sartore, National Geogrphic Photo Ark

Sunda pangolin

(critically endangered)

Eight species of the shy, scale-armored pangolin are found in Asia and Africa—but in ever fewer numbers. In 2016, commercial trade in all pangolin species was banned by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Despite the ban, the market for the pangolin’s meat and keratin scales (used in traditional Chinese medicine) is so lucrative that the illegal trade persists. The Sunda pangolin is the mostly widely distributed pangolin species in Asia, ranging across much of Southeast Asia. Even so, it’s classified as critically endangered—and it and the seven other pangolin species are identified as the most trafficked mammals in the world.