The world’s tallest land mammals may be slipping toward extinction, with three of the nine subspecies of giraffes now in serious trouble and considered “critically endangered.”

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That's according to a new report from the International Union for Conservation of Nature.

While giraffe populations in southern Africa are doing fine, the animal "is under severe pressure in some of its core ranges across East, Central and West Africa," according to Dr. Julian Fennessy, co-chair of the IUCN Species Survival Commission and director of the Giraffe Conservation Foundation.

Fennessy said even some conservationists were surprised by the declining number of giraffes in some areas in Africa.

“I am absolutely amazed that no one has a clue,” Fennessy told the Telegraph.  “This silent extinction. Some populations less than 400. That is more endangered than any gorilla, or almost any large mammal in the world.”

The giraffes' height and excellent vision give them a wide view of the grasslands where they live, making it easy to spot predators from a distance. Some scientists believe that other animals—such as zebras, antelope, and wildebeests—often congregate near giraffes to take advantage of their ability to see danger from a distance, according to National Geographic.

Credit: Pixabay

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Credit: Pixabay

The report also detailed a conservation success story.

Two giraffe subspecies (the West African and Rothchild’s giraffe) that were previously considered endangered have rebounded with efforts from African governments and conservation groups and have been downgraded to “vulnerable” and “near threatened,” respectively.

"This is a conservation success story and highlights the value of making proactive giraffe conservation management efforts in critical populations across the continent," Arthu Muneza, the East Africa Coordinator of the Giraffe Conservation Foundation, said.

The IUCN said the northern giraffe and the reticulated giraffe are two of the most threatened species with fewer than 5,200 and 15,785, respectively, remaining in the wild.

The threats facing giraffes include illegal hunting and civil unrest in parts of Africa and habitat loss due to mining and agriculture.