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A vulnerable species is any kind of species that is at risk of becoming endangered, and eventually extinct. Often, species are vulnerable because they have lost their homes. Vulnerable species have a steady drop in population over time. These species need the circumstances threatening its survival and reproduction to improve.


  • Vulnerable Species: A group of organisms at a high risk of becoming endangered.
  • Endangered Species: Any organism that is at a very high risk of becoming extinct. 
  • Extinct Species:  A species becomes extinct when the last existing member of that species dies.

What causes a species to become vulnerable?

  • Habitat loss or fragmentation: When a species’ natural habitat is destroyed or fragmented, it may lose access to food, water, shelter, and breeding sites.
  • Overexploitation: When a species is hunted or harvested beyond sustainable levels, its population size may decline to a level where it is no longer viable.
  • Climate change: Climate change can affect a species’ distribution, food availability, and breeding patterns, which can lead to declines in population size.
  • Pollution: Exposure to pollutants can harm a species’ health and reduce its ability to reproduce and survive.
  • Invasive species: Invasive species can outcompete native species for resources, which can lead to declines in population size.
  • Disease: Animal populations can suffer from epidemics and pandemics which can threaten their existence.


The International Union for the Conservation of Nature (IUCN) has a list of things known to make a species vulnerable. Species must meet one of the following requirements to be considered “vulnerable.” (Research from National Geographic)

vulnerable species criteria

Population Reduction Rate

  • There are two ways scientists track populations. First, they can track the population reduction rate over a decade (10-year period). Second, they can measure over three generations of the species (grandparents, parents, children). 
  • When the population of a species declines by 30% or more, the species is considered vulnerable. For example, if there are 4000 bears in a forest and the number declines to 2800 from a new disease, the bears are now “vulnerable.” 

Reduction in the Extent of Occurrence

  • In Biology, a species’ “extent of occurrence” refers to the smallest area in which a species can live and how many members of the species live there. These places are defined on a map.
  • A species is vulnerable when its extent of occurrence is less than 7,722 total square miles.
  • Additionally, a species is vulnerable if the population does not exist in more than ten places.
  • Loss of habitat causes a smaller extent of occurrence.

Population Size of Mature Individuals

  • A species is vulnerable if the population of mature individuals is less than 10,000.

Fragmented Population

  • The species’ population is severely fragmented, with more than 50% of individuals in small, isolated subpopulations.


A large number of animal species in the wild are considered vulnerable. This is due to harmful human activities. Currently, about 5,000 animal species are vulnerable: (Research from AZ animals)

examples of vulnerable species


  • The cheetah is the world’s fastest land animal. Cheetahs can go from 0-60 mph in just three seconds.
  • The population size of cheetahs in the wild is about 7,000. Habitat loss is the biggest threat to the cheetah population. Cheetahs are also hunted and killed by humans.
  • 79% of the cheetah habitats in the wild have less than 100 adult cheetahs.

Wandering Albatross

  • The Wandering Albatross has the widest wingspan of all living birds. On average, Albatrosses have an 11-foot wingspan.
  • Out of the 22 Albatross species, 7 are vulnerable. The population of these birds is falling due to fishing activities that harm them.
  • As of now, there are only about 25,000 Wandering Albatross in the wild.

Polar Bears

  • The main threat to polar bears is climate change. Global warming is causing the arctic ice to melt. The ice in these regions is important to polar bears. 
  • Polar bears use ice to hunt, travel and find mates.  Currently, there are around 25,000 polar bears in the world.
  • Some Scientists think polar bears will go extinct within the next 30 years.


  • The IUCN lists lions as a vulnerable species. In fact, lions are endangered in some African countries.
  • Their numbers are falling quickly as a result of human-lion conflicts and habitat loss.
  • The population size of lions in the wild is about 20,000.

Snow Leopard

  • Snow leopards are mainly found in Europe.
  • The population of snow leopards is falling due to habitat loss and hunting.
  • There are about 5,000 snow leopards left in the wild.


The Philippines is one of the most biodiverse places in the world. Some of the plant and animal species in the Philippines are not anywhere else on the planet. (Research from Mongabay)

Philippines and species
  • Many animal species in the Philippines are vulnerable or endangered.
  • The IUCN says more than 400 animal species in the area are vulnerable.
  • Poaching, or illegal hunting, is the main problem. Animals are also losing their habitats due to deforestation. Deforestation is the cutting down of trees. 
  • The Palawan fruit bat, Gray’s monitor, Philippine porcupine, and Sarangani Tiger are some examples of vulnerable species in the Philippines.


There have been many species that have died out over time. Extinction is a slow process that can take hundreds or even thousands of years to happen. It all starts with a species’ vulnerability and then gets worse until it’s in real danger.

It is only possible to save vulnerable species if we act quickly to change the unfavorable conditions that threaten their existence. This is what you need to do to help animals and their habitats.

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