An endangered species is defined by the U.S. Fish & Wildlife Service as "an animal or plant species in danger of extinction throughout all or a significant portion of its range." In the United States, these animals can be listed under and protected by the Endangered Species Act. Endangered Species in the United States include the black-footed ferret and the California red-legged frog. The International Union for Conservation of Nature also keeps a Red List of Threatened Species, the most widely recognized list of endangered and threatened species. On this list, for example, are all the surviving subspecies of tiger, which range from endangered to critically endangered.
Latest about endangered species
How many species of insects are there on Earth?
The number of insect species is mind-boggling — and they are a critical part of the environment.
Rat poison is ripping through the food chain, threatening predators at the very top
Rat poison detected in around a third of wild mammal carnivores — including those that don't normally eat rodents, such as mountain lions and gray wolves.
Feral cats ate critically endangered baby crocodiles in Cuba, study suggests
Two biologists say 145 young Cuban crocodiles that were taken by predators in fall 2022 were killed by feral cats.
Smalltooth sawfish in Florida are spinning and beaching themselves in strange, mystery die-off
Erratically thrashing and whirling smalltooth sawfish are stranding on beaches — and scientists don't know why they're behaving this way.
American burying beetle: The meat-eating insect that buries bodies for its babies to feast on
American burying beetle parents work together to find and bury a dead animal that its brood can consume after hatching.
Adorable but deadly little wildcat may be inbreeding at 'alarming' rates, study finds
Black footed cats are already a threatened species, and habitat fragmentation is now causing increased rates of interbreeding, placing them at higher risk of disease.
Hammerhead sharks are vanishing from their mountain homes in the Gulf of California, divers say
Scalloped hammerhead sharks used to seek refuge at two Mexican seamounts, but it appears fishing has killed them off.
Earless monitor lizards: The 'Holy Grail' of reptiles that looks like a mini dragon
Researchers are only beginning to understand the cryptic lives of the earless monitor lizards of Borneo.
10 times humans messed with nature and it backfired
History is peppered with times when our patchy knowledge of natural systems has led to questionable interventions with unintended — and sometimes disastrous — consequences.
Every year, dozens of female hammerhead sharks mysteriously convene in French Polynesia under the full moon
Every austral summer, Rangiroa and Tikehau atolls in French Polynesia host a mysterious assembly of female great hammerhead sharks — a critically endangered and typically solitary species.
