Vulnerable Species: Meaning and Examples of Vulnerable Animals

A vulnerable species is a plant or animal that the IUCN Red List judges to face a high risk of extinction in the wild. It is the lowest of the three “threatened” levels, below Endangered and Critically Endangered. This guide explains the label, the rules behind it and nine animals that carry it.

Vulnerable animals are one part of the wider story of wildlife and its roles in nature. For that bigger picture, read our main guide to animals of the ecosystem and their ecological importance.

What does “vulnerable species” mean?

The term comes from the IUCN Red List of Threatened Species, kept by the International Union for Conservation of Nature (IUCN). It sorts species by how likely they are to die out.

The rules are set out in the IUCN Red List Categories and Criteria, Version 3.1 (approved by IUCN’s Council in 2000; second edition 2012). Its definition: a taxon is Vulnerable when the best available evidence shows it meets any of the criteria A to E for Vulnerable. It is then considered to face a high risk of extinction in the wild. A taxon (plural taxa) simply means a named group of living things, usually a species.

Note the words “in the wild”: a species can be common in zoos and still be Vulnerable in nature. Meeting any one criterion is enough.

Where does Vulnerable sit among the IUCN Red List categories?

Version 3.1 has nine categories, from Extinct to Not Evaluated. Vulnerable sits just above Near Threatened, at the bottom of the three threatened levels:

IUCN groups CR, EN and VU together as threatened. Each category is explained in our guide to the IUCN Red List categories from Extinct to Least Concern.

What are the criteria for a vulnerable species?

IUCN uses five criteria, labelled A to E. Here are the thresholds for Vulnerable in simple words (IUCN, 2012):

1. A. Population reduction. The population has fallen, or is expected to fall, by at least 30% over ten years or three generations, whichever is longer. If the causes are clearly understood, reversible and have stopped, the bar is a fall of at least 50%.
2. B. Small geographic range. The species lives within an extent of occurrence under 20,000 km², or an area of occupancy under 2,000 km². It must also meet at least two of three conditions: severe fragmentation or no more than ten locations, a continuing decline, or extreme fluctuations.
3. C. Small and declining population. Fewer than 10,000 mature individuals. There must also be a decline of at least 10% in ten years or three generations (C1). Or there is a continuing decline with small subpopulations or extreme fluctuations (C2).
4. D. Very small or restricted population. Fewer than 1,000 mature individuals (D1). A second test (D2), used only for Vulnerable, covers species with very few sites and a threat that could rapidly worsen their status.
5. E. Quantitative analysis. A population analysis (often a computer model) shows at least a 10% chance of extinction in the wild within 100 years.

Extent of occurrence is the area inside the outer boundary of all known sites of a species. Area of occupancy is the smaller area it actually uses within that boundary. A generation here means the average age of parents in the population, so three generations can be a long time for slow-breeding animals.

How is a vulnerable species different from endangered and critically endangered?

All three categories use the same five criteria; only the severity changes. The table compares the main thresholds from IUCN’s 2012 summary sheet.

The polar bear shows how the line is drawn in practice. In its 2015 assessment, the IUCN Polar Bear Specialist Group modelled future sea ice and bear numbers over three generations. The median chance of a fall of more than 30% was about 0.71. The chance of a fall of more than 50% was only about 0.07. So the bear met the Vulnerable threshold but not the Endangered one.

For species at the top of the scale, see our list of critically endangered animals. For those one step above Vulnerable, browse endangered animals: pictures, names and facts.

What are some examples of vulnerable animals?

The table lists nine vulnerable animals, each with the source and year of its status.

BirdLife International is the official Red List Authority for birds. It is responsible for assessing the global status of every known bird species.

Polar bear

The polar bear hunts seals from Arctic sea ice. The 2015 assessment by the IUCN Polar Bear Specialist Group listed it as Vulnerable under criterion A3c, a projected population fall. It names sea-ice loss through climate change as the most serious threat. It has held that label in most years since 1982. Read more about its icy home in our guide to Arctic animals and their adaptations.

Dugong

The dugong is a plant-eating marine mammal often called the sea cow. IUCN World Conservation Congress Resolution 8.025 (2025) records that dugongs are classed as Vulnerable on the Red List. It adds that they play a vital role in keeping seagrass ecosystems healthy. The same resolution recognises India’s first Dugong Conservation Reserve, declared by Tamil Nadu in September 2022. It covers 448.34 km² of Palk Bay.

Olive ridley turtle

NOAA Fisheries says the olive ridley is among the smallest sea turtles, but the most widespread and abundant. Its management overview, last updated in September 2026, lists it as Vulnerable on the IUCN Red List. Some populations nest together in huge groups called arribadas. NOAA lists three arribada beaches in Odisha, India: Gahirmatha, Devi River mouth and Rushikulya. NOAA names fishing bycatch and the harvest of turtles and eggs as its most significant threats.

Andean condor

The Andean condor is a huge vulture of the Andes. In February 2021 BirdLife reported that it was now considered Vulnerable as of the latest Red List update. It estimated only around 7,000 adults across the bird’s range. Poisoning tops its list of threats. The bird features in our list of famous bird species around the world.

Grey plover and curlew sandpiper

These two shorebirds feed on beaches and mudflats. BirdLife’s 2024 Red List update moved both into the Vulnerable category. The grey plover was raised from Least Concern and the curlew sandpiper from Near Threatened. Each has declined by more than 30%, with habitat loss, disturbance and hunting among the likely causes. Both are long-distance travellers; learn how such journeys work in migratory birds: meaning and examples.

Black robin

The black robin lives only on New Zealand’s Chatham Islands. Rats and other introduced mammals drove it down to just seven birds by 1976. Conservationists then used cross-fostering, placing its eggs in the nests of a related bird so the robins would lay again. BirdLife’s 2022 update reported a stable population of 300 birds across two islands. That recovery moved it down from Endangered to Vulnerable.

Gang-gang cockatoo

This cockatoo is one of the Australian birds hit by recent wildfires. It was already declining because of logging. BirdLife’s 2022 update says the 2019-2020 “black summer” bushfires then wiped out an estimated 21% of its global population. It is now listed as Vulnerable.

Bornean bristlehead

The Bornean bristlehead is the sole member of its bird family. BirdLife’s 2022 update raised it from Near Threatened to Vulnerable because of forest loss on Borneo. BirdLife measured that loss with new satellite data on forest cover.

Can a species move in or out of the Vulnerable category?

Yes. The Red List is updated often, and IUCN asks for species to be re-evaluated at suitable intervals. Its rules for moving between categories are:

• A species may move to a lower threat category if it has not met the criteria of the higher one for five years or more.
• A move to a higher threat category should be made without delay.
• If an earlier listing was simply wrong, it can be corrected at once.

Recent bird updates show movement in both directions. In 2023 BirdLife moved the Lesser Adjutant, an Asian stork, from Vulnerable to Near Threatened. In the same update, the Great Bustard (a Eurasian bird, not the Great Indian Bustard) went the other way, from Vulnerable to Endangered. The black robin, as seen above, improved from Endangered to Vulnerable in 2022.

So treat every status as a snapshot. Before an exam or project, check the year of the assessment you are quoting.

Why do vulnerable species matter?

Vulnerable species are an early warning. Their numbers or ranges are shrinking in ways that could push them higher up the scale. BirdLife reported in 2024 that one in eight bird species is threatened with extinction. The main causes, such as habitat loss and over-exploitation, are explained in our article on the loss of biodiversity and its causes.