The monarch butterfly (Danaus plexippus) is an iconic pollinator species, this individual is nectaring on a common garden flower, a zinnia (Zinnia spp.) This species of butterfly has a complex life history style including seasonal migration across the United States and into neighboring Mexico.
What are the differences between endangered, threatened, imperiled, and at-risk species?
Under the Endangered Species Act (ESA), plant and animal species may be listed as either endangered or threatened. “Endangered” means a species is in danger of extinction throughout all or a significant portion of its range. “Threatened” means a species is likely to become endangered within the foreseeable future.
States have their own ESA-type laws, so species can have different Threatened/Endangered statuses at the federal and state levels. The USGS typically refers to the federal status unless otherwise noted.
"Imperiled" or "at risk" are not legal terms under ESA, but more biological terms. Generally speaking, they are animals and plants that are in decline and may be in danger of extinction. Those terms can include species that are at low populations and near extinction but still not legally protected under ESA.
Related
Are salmon endangered worldwide?
No, salmon are not endangered worldwide. For example, most populations in Alaska are healthy. Some populations in the Pacific Northwest are much healthier than others. These healthy populations usually occupy protected habitats such as the Hanford Reach on the Columbia River and streams of Olympic National Park. Learn more: Western Fisheries Research Center - Questions and Answers about Salmon
What is the threat from West Nile Virus (WNV) to endangered and threatened bird species?
This is an issue of great concern, as these populations are already struggling to survive in the current environment. If some of these species are more vulnerable to fatal WNV infection, WNV may ultimately lead to their extinction or significantly set back the progress of the recovery programs.
Where are salmon most endangered?
Certain populations of sockeye salmon, coho salmon, chinook salmon, and Atlantic salmon are listed as endangered. Sockeye salmon from the Snake River system are probably the most endangered salmon. Coho salmon in the lower Columbia River may already be extinct. Salmon are not endangered worldwide. For example, most populations in Alaska are healthy. Some populations in the Pacific Northwest are...
Why do animals and plants become endangered?
Although extinctions occur naturally, the current rate of plant and animal extinctions is much higher than the natural or historical rates. Habitat loss is the primary cause of higher extinction rates. Other causes include habitat changes, over-exploitation of wildlife for commercial purposes, the introduction of harmful nonnative species, pollution, and the spread of diseases. Learn more...
What species of bats are affected by White-nose Syndrome?
White-nose Syndrome mostly affects hibernating bats. More than half of the 47 bat species living in the United States and Canada hibernate to survive the winter. Twelve bat species, including two endangered species and one threatened species, have been confirmed with white-nose syndrome in North America. The causative fungus, Pseudogymnoascus destructans ( Pd), has been found on an additional six...
Monarch butterfly on zinnia
The monarch butterfly (Danaus plexippus) is an iconic pollinator species, this individual is nectaring on a common garden flower, a zinnia (Zinnia spp.) This species of butterfly has a complex life history style including seasonal migration across the United States and into neighboring Mexico.
Posing with an endangered bird crossing sign near light-footed Ridgway's rail habitat
Amy Vandergast (left) and Julia Smith (right) pose next to a rail crossing sign in Ventura County.
Amy Vandergast (left) and Julia Smith (right) pose next to a rail crossing sign in Ventura County.
Endangered Salt Marsh Harvest Mouse (Reithrodontomys raviventris)
A Federally endangered salt marsh harvest mouse (Reithrodontomys raviventris) climbs a branch.
A Federally endangered salt marsh harvest mouse (Reithrodontomys raviventris) climbs a branch.
An Endangered Honeycreeper, the ‘Akeke‘e (Kaua‘i Akepa), in Hawai‘i
Many species of Hawaiian honeycreepers have persisted into the 20th century because high elevation rain forests on the islands of Kaua’i, Maui, and Hawai’i are cool enough to limit transmission of introduced avian malaria (Plasmodium relictum).
Many species of Hawaiian honeycreepers have persisted into the 20th century because high elevation rain forests on the islands of Kaua’i, Maui, and Hawai’i are cool enough to limit transmission of introduced avian malaria (Plasmodium relictum).
Humpback Chub in the Colorado River, Grand Canyon
Humpback chub, a federally protected species, in habitat near the confluence of the Colorado River and Little Colorado Rivers in Grand Canyon. Photo by David Ward, USGS.
Humpback chub, a federally protected species, in habitat near the confluence of the Colorado River and Little Colorado Rivers in Grand Canyon. Photo by David Ward, USGS.
An Endangered Puaiohi (Small Mountain Thrush) in Hawaii
Many species of Hawaiian honeycreepers have persisted into the 20th century because high elevation rain forests on the islands of Kaua’i, Maui, and Hawai'i are cool enough to limit transmission of introduced avian malaria (Plasmodium relictum).
Many species of Hawaiian honeycreepers have persisted into the 20th century because high elevation rain forests on the islands of Kaua’i, Maui, and Hawai'i are cool enough to limit transmission of introduced avian malaria (Plasmodium relictum).
Green Sea Turtle Swimming in Dry Tortugas National Park
A green sea turtle, sporting a USGS satellite tag, swims the waters of Dry Tortugas National Park, Florida, USA. Note: All marine turtle images taken in Florida were obtained with the approval of the U.S. Fish & Wildlife Service (USFWS) and the Florida Fish & Wildlife Conservation Commission (FWC) under conditions not harmful to this or other turtles.
A green sea turtle, sporting a USGS satellite tag, swims the waters of Dry Tortugas National Park, Florida, USA. Note: All marine turtle images taken in Florida were obtained with the approval of the U.S. Fish & Wildlife Service (USFWS) and the Florida Fish & Wildlife Conservation Commission (FWC) under conditions not harmful to this or other turtles.
Female Pallid Sturgeon
Biologists prepare to perform ultrasound and an egg biopsy on female pallid sturgeon, radio code 30, to determine how close to spawning she is or whether spawning may already have occurred. Biologists from Montana Fish, Wildlife and Parks determined that code 30 eventually spawned in the Yellowstone River on July 19-20, 2012.
Biologists prepare to perform ultrasound and an egg biopsy on female pallid sturgeon, radio code 30, to determine how close to spawning she is or whether spawning may already have occurred. Biologists from Montana Fish, Wildlife and Parks determined that code 30 eventually spawned in the Yellowstone River on July 19-20, 2012.
An Endangered Yellow-Legged Frog
USGS biologists are leading the monitoring and reintroduction effort of the Southern California mountain yellow-legged frog -- federally listed as endangered with only 200 wild adults remaining in the mountains surrounding Los Angeles County.
USGS biologists are leading the monitoring and reintroduction effort of the Southern California mountain yellow-legged frog -- federally listed as endangered with only 200 wild adults remaining in the mountains surrounding Los Angeles County.
An Endangered Humpback Chub
The Colorado River basin supports one of the most distinctive fish communities in North America, including the federally endangered humpback chub (Gila cypha). One of only six remaining populations of this fish is found in Grand Canyon National Park, Arizona. USGS scientists and their cooperators are responsible for monitoring the Grand Canyon population.
The Colorado River basin supports one of the most distinctive fish communities in North America, including the federally endangered humpback chub (Gila cypha). One of only six remaining populations of this fish is found in Grand Canyon National Park, Arizona. USGS scientists and their cooperators are responsible for monitoring the Grand Canyon population.
Big Invaders and Tiny Fish: Endangered Species Day
Kids! Listen up—it's Endangered Species Day, and we have two podcasts for you: giant, invasive predators that eat endangered animals, and the tiny Devil's Hole pupfish, which lives on a watery shelf no bigger than a walk-in closet.
Kids! Listen up—it's Endangered Species Day, and we have two podcasts for you: giant, invasive predators that eat endangered animals, and the tiny Devil's Hole pupfish, which lives on a watery shelf no bigger than a walk-in closet.
Public Lecture: Flight from Extinction: Helping Whooping Cranes Survive
- Scientists and volunteers are working to restore the Eastern population of the federally listed whooping crane
- The life history and migration of whooping cranes
- Scientists and volunteers are working to restore the Eastern population of the federally listed whooping crane
- The life history and migration of whooping cranes
An Endangered Red Hawksbill Sea Turtle Swims Over a Threatened Elkhorn Coral in Virgin Islands National Park
linkThis photo shows an endangered hawksbill (Eretmochelys imbricata) swimming over a colony of elkhorn coral (Acropora palmata).
USGS scientists are doing research on sea turtles and corals in Florida and the US Virgin Islands.
An Endangered Red Hawksbill Sea Turtle Swims Over a Threatened Elkhorn Coral in Virgin Islands National Park
linkThis photo shows an endangered hawksbill (Eretmochelys imbricata) swimming over a colony of elkhorn coral (Acropora palmata).
USGS scientists are doing research on sea turtles and corals in Florida and the US Virgin Islands.
Hawksbill Sea Turtle (Eretmochelys imbricata)
Hawksbill Sea Turtles (Eretmochelys imbricata), such as the one hiding here under a boulder, and Green Sea Turtles (Chelonia mydas) are occasionally seen in Hurricane Hole. Hawksbills feed mostly on sponges while Greens eat mostly sea grasses.
Hawksbill Sea Turtles (Eretmochelys imbricata), such as the one hiding here under a boulder, and Green Sea Turtles (Chelonia mydas) are occasionally seen in Hurricane Hole. Hawksbills feed mostly on sponges while Greens eat mostly sea grasses.
Endangered California Condor
An endangered California condor flies over the Bitter Creek National Wildlife Refuge, California.
An endangered California condor flies over the Bitter Creek National Wildlife Refuge, California.
Endangered Burrowing Owl
An endangered Burrowing Owl near a site in Cape Coral, FL.
An endangered Burrowing Owl near a site in Cape Coral, FL.
Endangered Hawaiian Hoary Bat
An endangered Hawaiian hoary bat, a species that is sometimes killed by wind turbines.
An endangered Hawaiian hoary bat, a species that is sometimes killed by wind turbines.
Related
Are salmon endangered worldwide?
No, salmon are not endangered worldwide. For example, most populations in Alaska are healthy. Some populations in the Pacific Northwest are much healthier than others. These healthy populations usually occupy protected habitats such as the Hanford Reach on the Columbia River and streams of Olympic National Park. Learn more: Western Fisheries Research Center - Questions and Answers about Salmon
What is the threat from West Nile Virus (WNV) to endangered and threatened bird species?
This is an issue of great concern, as these populations are already struggling to survive in the current environment. If some of these species are more vulnerable to fatal WNV infection, WNV may ultimately lead to their extinction or significantly set back the progress of the recovery programs.
Where are salmon most endangered?
Certain populations of sockeye salmon, coho salmon, chinook salmon, and Atlantic salmon are listed as endangered. Sockeye salmon from the Snake River system are probably the most endangered salmon. Coho salmon in the lower Columbia River may already be extinct. Salmon are not endangered worldwide. For example, most populations in Alaska are healthy. Some populations in the Pacific Northwest are...
Why do animals and plants become endangered?
Although extinctions occur naturally, the current rate of plant and animal extinctions is much higher than the natural or historical rates. Habitat loss is the primary cause of higher extinction rates. Other causes include habitat changes, over-exploitation of wildlife for commercial purposes, the introduction of harmful nonnative species, pollution, and the spread of diseases. Learn more...
What species of bats are affected by White-nose Syndrome?
White-nose Syndrome mostly affects hibernating bats. More than half of the 47 bat species living in the United States and Canada hibernate to survive the winter. Twelve bat species, including two endangered species and one threatened species, have been confirmed with white-nose syndrome in North America. The causative fungus, Pseudogymnoascus destructans ( Pd), has been found on an additional six...
Monarch butterfly on zinnia
The monarch butterfly (Danaus plexippus) is an iconic pollinator species, this individual is nectaring on a common garden flower, a zinnia (Zinnia spp.) This species of butterfly has a complex life history style including seasonal migration across the United States and into neighboring Mexico.
The monarch butterfly (Danaus plexippus) is an iconic pollinator species, this individual is nectaring on a common garden flower, a zinnia (Zinnia spp.) This species of butterfly has a complex life history style including seasonal migration across the United States and into neighboring Mexico.
Posing with an endangered bird crossing sign near light-footed Ridgway's rail habitat
Amy Vandergast (left) and Julia Smith (right) pose next to a rail crossing sign in Ventura County.
Amy Vandergast (left) and Julia Smith (right) pose next to a rail crossing sign in Ventura County.
Endangered Salt Marsh Harvest Mouse (Reithrodontomys raviventris)
A Federally endangered salt marsh harvest mouse (Reithrodontomys raviventris) climbs a branch.
A Federally endangered salt marsh harvest mouse (Reithrodontomys raviventris) climbs a branch.
An Endangered Honeycreeper, the ‘Akeke‘e (Kaua‘i Akepa), in Hawai‘i
Many species of Hawaiian honeycreepers have persisted into the 20th century because high elevation rain forests on the islands of Kaua’i, Maui, and Hawai’i are cool enough to limit transmission of introduced avian malaria (Plasmodium relictum).
Many species of Hawaiian honeycreepers have persisted into the 20th century because high elevation rain forests on the islands of Kaua’i, Maui, and Hawai’i are cool enough to limit transmission of introduced avian malaria (Plasmodium relictum).
Humpback Chub in the Colorado River, Grand Canyon
Humpback chub, a federally protected species, in habitat near the confluence of the Colorado River and Little Colorado Rivers in Grand Canyon. Photo by David Ward, USGS.
Humpback chub, a federally protected species, in habitat near the confluence of the Colorado River and Little Colorado Rivers in Grand Canyon. Photo by David Ward, USGS.
An Endangered Puaiohi (Small Mountain Thrush) in Hawaii
Many species of Hawaiian honeycreepers have persisted into the 20th century because high elevation rain forests on the islands of Kaua’i, Maui, and Hawai'i are cool enough to limit transmission of introduced avian malaria (Plasmodium relictum).
Many species of Hawaiian honeycreepers have persisted into the 20th century because high elevation rain forests on the islands of Kaua’i, Maui, and Hawai'i are cool enough to limit transmission of introduced avian malaria (Plasmodium relictum).
Green Sea Turtle Swimming in Dry Tortugas National Park
A green sea turtle, sporting a USGS satellite tag, swims the waters of Dry Tortugas National Park, Florida, USA. Note: All marine turtle images taken in Florida were obtained with the approval of the U.S. Fish & Wildlife Service (USFWS) and the Florida Fish & Wildlife Conservation Commission (FWC) under conditions not harmful to this or other turtles.
A green sea turtle, sporting a USGS satellite tag, swims the waters of Dry Tortugas National Park, Florida, USA. Note: All marine turtle images taken in Florida were obtained with the approval of the U.S. Fish & Wildlife Service (USFWS) and the Florida Fish & Wildlife Conservation Commission (FWC) under conditions not harmful to this or other turtles.
Female Pallid Sturgeon
Biologists prepare to perform ultrasound and an egg biopsy on female pallid sturgeon, radio code 30, to determine how close to spawning she is or whether spawning may already have occurred. Biologists from Montana Fish, Wildlife and Parks determined that code 30 eventually spawned in the Yellowstone River on July 19-20, 2012.
Biologists prepare to perform ultrasound and an egg biopsy on female pallid sturgeon, radio code 30, to determine how close to spawning she is or whether spawning may already have occurred. Biologists from Montana Fish, Wildlife and Parks determined that code 30 eventually spawned in the Yellowstone River on July 19-20, 2012.
An Endangered Yellow-Legged Frog
USGS biologists are leading the monitoring and reintroduction effort of the Southern California mountain yellow-legged frog -- federally listed as endangered with only 200 wild adults remaining in the mountains surrounding Los Angeles County.
USGS biologists are leading the monitoring and reintroduction effort of the Southern California mountain yellow-legged frog -- federally listed as endangered with only 200 wild adults remaining in the mountains surrounding Los Angeles County.
An Endangered Humpback Chub
The Colorado River basin supports one of the most distinctive fish communities in North America, including the federally endangered humpback chub (Gila cypha). One of only six remaining populations of this fish is found in Grand Canyon National Park, Arizona. USGS scientists and their cooperators are responsible for monitoring the Grand Canyon population.
The Colorado River basin supports one of the most distinctive fish communities in North America, including the federally endangered humpback chub (Gila cypha). One of only six remaining populations of this fish is found in Grand Canyon National Park, Arizona. USGS scientists and their cooperators are responsible for monitoring the Grand Canyon population.
Big Invaders and Tiny Fish: Endangered Species Day
Kids! Listen up—it's Endangered Species Day, and we have two podcasts for you: giant, invasive predators that eat endangered animals, and the tiny Devil's Hole pupfish, which lives on a watery shelf no bigger than a walk-in closet.
Kids! Listen up—it's Endangered Species Day, and we have two podcasts for you: giant, invasive predators that eat endangered animals, and the tiny Devil's Hole pupfish, which lives on a watery shelf no bigger than a walk-in closet.
Public Lecture: Flight from Extinction: Helping Whooping Cranes Survive
- Scientists and volunteers are working to restore the Eastern population of the federally listed whooping crane
- The life history and migration of whooping cranes
- Scientists and volunteers are working to restore the Eastern population of the federally listed whooping crane
- The life history and migration of whooping cranes
An Endangered Red Hawksbill Sea Turtle Swims Over a Threatened Elkhorn Coral in Virgin Islands National Park
linkThis photo shows an endangered hawksbill (Eretmochelys imbricata) swimming over a colony of elkhorn coral (Acropora palmata).
USGS scientists are doing research on sea turtles and corals in Florida and the US Virgin Islands.
An Endangered Red Hawksbill Sea Turtle Swims Over a Threatened Elkhorn Coral in Virgin Islands National Park
linkThis photo shows an endangered hawksbill (Eretmochelys imbricata) swimming over a colony of elkhorn coral (Acropora palmata).
USGS scientists are doing research on sea turtles and corals in Florida and the US Virgin Islands.
Hawksbill Sea Turtle (Eretmochelys imbricata)
Hawksbill Sea Turtles (Eretmochelys imbricata), such as the one hiding here under a boulder, and Green Sea Turtles (Chelonia mydas) are occasionally seen in Hurricane Hole. Hawksbills feed mostly on sponges while Greens eat mostly sea grasses.
Hawksbill Sea Turtles (Eretmochelys imbricata), such as the one hiding here under a boulder, and Green Sea Turtles (Chelonia mydas) are occasionally seen in Hurricane Hole. Hawksbills feed mostly on sponges while Greens eat mostly sea grasses.
Endangered California Condor
An endangered California condor flies over the Bitter Creek National Wildlife Refuge, California.
An endangered California condor flies over the Bitter Creek National Wildlife Refuge, California.
Endangered Burrowing Owl
An endangered Burrowing Owl near a site in Cape Coral, FL.
An endangered Burrowing Owl near a site in Cape Coral, FL.
Endangered Hawaiian Hoary Bat
An endangered Hawaiian hoary bat, a species that is sometimes killed by wind turbines.
An endangered Hawaiian hoary bat, a species that is sometimes killed by wind turbines.
Updated Date: April 11, 2025