These are the 10 fastest declining species in the world

Wildlife extinction is a global crisis. Poaching often makes the headlines, but habitat loss and environmental pollution are also major killers.

There are currently 17 animals on the World Wildlife Fund’s (WWF) critically endangered list, including three species of rhino, six primates, and two big cats.

Five of the species on the list have approximately 100 animals or fewer left on the planet, including the Saola, of which there are only around 20 still roaming the mountains of the Vietnam-Laos border.

On the other side of the globe, the Vaquita is also on the verge of extinction – a porpoise found only in the northern Gulf of California with numbers now as low as 10.

While all of the species on the WWF’s critically endangered list are at risk, some of them are on their way to becoming completely extinct. Ethical travel company Volunteering Solutions has gone through the official list to find out which species is reducing in numbers the fastest.

10. Sunda Tiger

This magisterial tiger, native to Indonesia, is decreasing at a rate of 19 per cent every decade.

9. Sumatran Elephant

As one of the three recognised subspecies of Asian Elephant, the Sumatran is also native to Indonesia and is decreasing at a rate of 19 per cent every decade.

8. Bornean Orangutan

These highly intelligent orangutans are native to Borneo and are decreasing at a rate of 20 per cent every decade.

7. Eastern Lowland Gorilla

The majestic Eastern Lowland gorilla, sometimes called Grauer's gorilla, is endemic to the mountainous forests of the eastern Democratic Republic of the Congo. They are decreasing at a rate of 24 per cent every decade.

6. Yangtze Finless Porpoise

This rare and endangered Chinese river porpoise is decreasing at a rate of 33 per cent every decade.

5. Sumatran Rhino

Sumatran rhinos are the smallest of the living rhinoceroses and the only Asian rhino with two horns. Sadly, they are decreasing at a rate of 35 per cent every decade.

4. African Forest Elephant

The African Forest Elephant is native to humid forests in West Africa and the Congo Basin, the species is decreasing by 47 per cent every decade.

3. Cross River Gorilla

This increasingly rare great ape lives in the forested hills and mountains of the Cameroon-Nigeria border region at the headwaters of the Cross River (Nigeria). The species is decreasing at a rate of 51 per cent every decade.

2. Vaquita

The vaquita is a small porpoise found only in the northern Gulf of California (Sea of Cortez) in Mexico and is an animal that always looks like it’s smiling.

The species is decreasing at a rate of 76 per cent every decade, meaning it is likely to be completely extinct by 2050.

1. Saola

The saola, also called the Asian unicorn, is a beautiful bovine creature and one of the world's rarest large mammals. It lives in forests in the Annamite Range of Vietnam and Laos.

The saola is decreasing by a whopping 80 per cent every decade, meaning that it is likely to be completely extinct by 2050.