Arxiu d'etiquetes: international union conservation species

What is IUCN and its Red List?

A lot it is talked about endangered, critically endangered and vulnerable species. In fact, in this blog we have given some examples: Mediterranean monk seal is an example of a critically endangered species and Iberian lynx of an endangered species. But, which is the meaning of these names? Who is responsible of categorising them and how do they do it? Here, there are the answers. 


Have you ever seen this logo in some report or in Internet?

logo iucn uicn
International Union for Conservation of Nature logo (Pictrure: IUCN).

The International Union for Conservation of Nature (IUCN) is a union with more than 1,000 government and NGO member organizations, and about 11,000 scientists from 160 countries.

Its purpose is to preserve nature and, for this reason, it seeks to solve the most urgent environmental problems.

The IUCN is composed by 6 commissions, among which there is the Species Survival Commission (SSC), which have more than 10,000 volunteer experts from all over the world, distributed in different working groups.

The IUCN and the Species Survival Commission are the responsibles of elaborating the Red List. What is a Red List?


The red list of threatened species is an inventory of the the conservation state of plant, animal and fungi species. So, it evaluates the risk of extinction of a species in case no conservation actions are taken.

Lista Roja de la Flora Vascular Española 2008. (Imagen: Jolube).
Red List of Spanish Vascular Flora 2008. (Picture: Jolube).

This list is produced following objective criteria that permit to classify species in 8 threat categories, so that it is easier to compare different taxa. Let’s see them!



To use these criteria, some requirements have to be followed:

  • They can be applied to species and lower taxonomic levels.
  • They can only be applied to wild populations in their natural distribution and to populations resulting from benign introductions.
  • Criteria have to be applied to taxon whatever the level of conservation action affecting it.
  • The conservation status of a species doesn’t have to be necessarily the same in a global scale or a regional or national scale.


From less to more extinction risk, evaluated taxa can be classified in one of the following categories:

  • Least concern (LC): when a taxon cannot be classified in any of the following categories, it is said that there is a least concern for its conservation.
  • Near Threatened (NT): when a taxon cannot be classified in any of the following categories, but is close, it is said that is near threatened because in the near future it will possibly classified in some of them. The dwarf cassowary (Casuarius bennetti), a bird that could be the current velociraptor, has this category.
quandong, cassowary, eating, fruit
Cassowary eating quandongs, one of its favourite fruits (Picture: Christian Ziegler).
  • Vulnerable (VU): when a taxon is considered to be facing a high risk of extinction in the wild, it is classified as vulnerable. Two examples are whale shark and the basking shark, the two biggest fishes in the world and feed on plankton.
  • Endangered (EN): a taxon is endangered when faces a very high risk of extinction in the wild. An example is the Iberian lynx (Lynx pardinus).
  • Critically Endangered (CR): a taxon is critically endangered when faces an extremely high risk of extinction in the wild. An example, it is the Mediterranean monk seal (Monachus monachus).
  • Extinct in the Wild (EW): it means that only survives in cultivation, in captivity or as a naturalized population well outside the past range.
  • Extinct (EX): a taxon is extinct when there is no doubt that the last individual has died. An example is the thylacine.
Un dels pocs llops marsupials que es conserven taxidermitzats en el món. Museo nacional de Ciencias Naturales, Madrid. Foto: Mireia Querol
Thylacine was extinct by humans. Museo nacional de Ciencias Naturales, Madrid (Picture: Mireia Querol).

Vulnerable, Endangered and Critically endangered categories are those that show a threatened condition of the species. So, an endangered and a threatened species are not exactly the same.

Moreover, there are two other categories for those species not evaluated:

  • Data deficient (DD): when there is inadequate information to make an assessment of its risk of extinction.
  • Not evaluated (NE): when it has not yet been evaluated.


5 are the criteria to evaluate the state of conservation of taxa:

  • Criterion A: Reduction in population size. It has to accomplish some of the following subcriteria (A1-A4), evaluating the reduction in the largest period, 10 years or 3 generations.
  Critically endangered Endangered Vulnerable

Reduction in the past where the causes are reversible, understood and have ceased

90% or more 70% or more 50% or more

Reduction in the past where the causes may no have ceased, may no be understood or may not be reversible

80% or more 50% or more 30% or more

Reduction in the future (up to 100 years)


80% or more 50% or more 30% or more

Reduction where the time period mus include both the past and the future (up to 100 years in the future) and where the causes may not have ceased, may not be understood or may not be reversible

80% or more 50% or more 30% or more
  • Criterion B: Geographic range either extent of occurrence or area of occupancy. Let’s see these concepts:
    • Extent of occurrence: when you draw a line that joints all the most external places where there is a taxon (and all the places are included), you find the extent of occurrence.
    • Area of occupancy: it refers to the area inside the extent of occurrence having into account that there is not present in all its extent of occurrence.
Dos ejemplos de la diferencia entre extensión de presencia y área de ocupación. (A) es la distribución espacial de dos especies, (B) es la delimitación de la extensión de presencia y (C) muestra una medida del área de ocupación (Foto: IUCN).
Two examples of the difference between extent of occurrence and area of occupancy. (A) is the spatial distribution of a species, (B) show  the extent of occurrence and (C) shows the area of occupancy (Picture: IUCN).
  Critically endangered Endangered Vulnerable

Extent of occurrence

Less than 100 km2 Less than 5.000 km2 Less than 20.000 km2

Area of occupancy

Less than 10 km2 Less than 500 km2 Les than 2.000 km2
  • Criterion C: Small size of the population and decline.
  Critically endangered Endangered Vulnerable
Number of mature individuals Less than 250

(and C1 and/or C2)

Less than 2.500

(and C1 and/or C2)

Less than 10.000

(and C1 and/or C2)


Continuing decline

At least 25% in 3 years or 1 generation (up to 100 years) At least 20% in 5 years or 2 generations (up to 100 years) At least 10% in 10 years or 3 generations (up to 100 years)

Continuing decline and at least one of the 3 conditions (2a.i, 2a.ii, 2b)


Number of mature individuals in each subpopulation

At least 50 At least 250 At least 1.000

% of individuals in one subpopulation

90-100% 95-100% 100%

Extreme fluctuations in the number of mature individuals

  • Criterion D: Very small population or restricted
  Critically endangered Endangered Vulnerable
Number of mature individuals Less than 250 Less than 2.500 Less than 10.000
  • Criterion E: Quantitative analysis 
  Critically endangered Endangered Vulnerable

Probability of extinction in the wild

At least 50% in 10 years or 3 generations (up to 100 years) At least 20% in 30 years or 5 generations (up to 100 years) At least 10% up to 100 years.

Despite there have to be evaluated all the criteria, with just one of them is enough to classify the species in the category.

The previous criteria are simplified because there are complementary conditions that have to be accomplished. For further details, read the document IUCN Red List Categories and Criteria.



Pangolin: poaching is condemning it to extinction

Neither the tiger or elephant or rhino: the most hunted mammals by humans are pangolins, to the point of critically threaten their survival as a species. Discover the only mammal with scales, its current condition and what can we do to prevent the extinction of all species of pangolin in the world.


manis tricuspis, pangolin, árbol, tree, trepando
Tree pangolin (Phataginus tricuspis). (Photo by Bart Wursten).

The name pangolin (also known as scaly anteater or trenggiling) includes 8 different species distributed by a variety of habitats (tropical rainforests, dry forests, savanna areas, cultivated fields…) in Africa and Asia. They measure between 90 cm and 1.65 m. They are the only family in the order Pholidota: although physically similar, armadillos, sloths and anteaters are not its relatives (order Xenarthra). Most are nocturnal, solitary and shy, so there are still many questions about their biology and behavior in the wild (they don’t usually survive captivity).


Pangolins are the only mammals with scales: they are made of keratin (like our nails) and give them a look like a pineapple or artichoke. Scales are very sharp and they can move them voluntarily. If pangolins feel threatened hiss and puff, curl into a ball leaving the scales exposed and secrete pestilential acids to ward off predators (tigers, lions, panthers and humans).

leon, leona, pangolin, bola, lion, defensa
An impenetrable defense even to a lioness. (Photo by Holly Cheese)

The claws allow them both climb as digging: terrestrial pangolins hide and breed in underground galleries and arboreal pangolins do the same in hollows on trees. The tail of the tree pangolin is prehensile to attach to the branches. In addition, pangolins are excellent swimmers.
They are mainly bipedal animals: forepaws are so large that force them to walk on its hind legs, with a maximum speed of 5 km/h. Watch a pangolin walking and feeding:


Pangolin has no teeth and is unable to chew. It feeds on ants and termites, which locates with its powerful sense of smell (the view is underdeveloped) and catch them with its sticky and long tongue (may be longer than the body itself, up to 40 cm). The stones swallowed involuntarily and corneal structures of their stomach help them to crush the exoskeletons of insects. With its powerful claws destroy their nests to access them and avoid their attack plugging his ears and nostrils, besides having an armored eyelid. It is estimated that a pangolin can consume about 70 million insects per year, which makes them important regulators of the population of ants and termites.

lengua, pangolin, tongue
The tongue of the pangolin. (Photo by Wim Vorster).


Pangolins can reproduce at any time of the year. After pregnancy (two to five months, depending on species) only one young is born (African species) or up to three (Asian species).

pangolin, hembra, female, mamas, breast, pecho, tetas
Female pangolin. (Photo by Scott Hurd)

The pangolin is born with soft scales, which begin to harden after two days. When after a month come out of the burrow, they travel on the tail of her mother and become independent at 3-4 months. Their lifespan is unknown, although in captivity an individual lived until 20 years old.

pangolin, baby, cría, zoo bali
Female with her baby in the tail. Bali zoo. (Photo by Firdia Lisnawati)


In addition to habitat destruction, the main threat that pangolins face is direct hunting for human consumption. Although there are international laws to protect them, it is estimated that about 100 000 pangolins are hunted annuallyGiven the defense strategy of this animal, poachers only have to catch them of the ground. Like other species, like sharks, the food market and traditional medicine are the main causes of directing the pangolin towards extinction.

pangolin, jaulas, tráfico ilega, illegal trade, bushmeat
Illegal trade in pangolin. (Photo by Soggydan Benenovitch).


  • Bushmeat is considered a delicacy and an indicator of high social status in Vietnam and China. The pangolin fetus soup is sold as an elixir to increase virility and improve breast milk production. The price of bushmeat on the black market can reach $ 300 per kilo. The price of an individual can reach $ 1,000.
sopa, feto, soup, pangolin, feto, fetus
Pangolin fetus soup. (Photo by TRAFFIC).
  • Blood is sold as a tonic to improve health and as an aphrodisiac.
  • Scales can reach $ 3000 per kilo and are used for almost anything: to cure from acne to cancer. This belief is curious, considering that the scales have the same structure as our fingernails.
pangolín, china, medicina, medicine, tradicional, cura para el cáncer
Products of traditional Chinese medicine made of pangolin. (Photo by TRAFFIC).

All these purported medicinal and magical effects have no scientific basis, making yet more nonsense pangolin smuggling.


The population trend of all species of pangolin is declining in some cases to an alarming extent. The IUCN (International Union for the Conservation of Nature) Red List of Threatened Species classifies them as it follows:

IUCN Red List categories. (Image from

Because of their status, IUCN restored in 2012 a group of specialists within the Species Survival Commission (SSC) dedicated to pangolins (Pangolin Specialist Group -PangolinSG-). Its main objective are do research to increase knowledge of pangolins, the threats they face and how they can be mitigated to facilitate preservation.

The conservation projects that are being carried out include campaigns to reduce the demand of bushmeat and pangolin scales and the tightening of laws. Still, the total ignorance of populations’ state and low survival in captivity for breeding makes it difficult to design strategies for their conservation.


  • Reject any product derived from this animal, either bushmeat, scales or “miracle” products for the cure of diseases. Read the labels of any traditional remedies, especially if they are from the Asian market, and recall that its hypothetical benefits have no scientific basis, so that you can rethink their use.
  • Share information. If you own new data on pangolins, photos or videos contact with PangolinSG to cooperate with the investigation. Talk about them in your immediate environment to raise awareness and publicize this fantastic single animal.
  • Do a PhD about pangolins. Lot of research on these species is still needed, so if you are a student and you are planning to do a PhD, you can collaborate with PangolinSG with your future research.
  • Become a PangolinSG volunteer. Get involved in the development and implementation of projects and conservation programs.
  • Make a financial donation so PangolinSG can continue its work.

In conclusion, more scientific research, a change of mind and protection policies are needed to prevent the pangolin become an example of extinct species at the hands of ours, as it is about to happen to white rhino.