A critically endangered primate on the verge of extinction appears to be recovering after conservationists discovered a new breeding pair.
The Hainan Gibbon is an ape only found on the forested Chinese island of the same name, and in the 1970s the worldwide population was less than ten.
However, half a century of dedicated conservation work has seen the world's rarest primate population slowly rise to more than 30.
A male and female have now been spotted in a new patch of forest and it is thought they are breeding and forming their own family group - the fifth on the island.
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A critically endangered primate on the verge of extinction appears to be recovering after conservationists discovered a new breeding pair
It is easy to identify a breeding pair, as a male is jet black, while females are a striking gold.
They are also extremely vocal animals, producing loud calls to mark their territory. These calls also double up as a way for males and females to strengthen their bond by singing duets as dawn breaks.
The new pair was spotted when these calls were heard in a new region of the forest. Patrols later confirmed the new pair.
This development is seen as being highly significant in the fight against the species' extinction.
Populations of the long-limbed, tree-dwelling ape were decimated in the 20th century due to habitat loss as their home was cut down to make space for farms.
Hunting and poaching was also a major driver of their decline.
As a result of the invasion of their habitat, numbers of the Hainan Gibbon went from around 2,000 in the 1950s to single figures by 1970.
In 2003, the first full census found only 13 individuals living on the island, and conservationists were faced with the stark reality of the crisis.
When the dire state of the primate population was revealed, the Hainan Gibbon Conservation Project, run by the Kadoorie Farm and Botanic Garden in Hong Kong, was established.
Since then, numbers have stabilised and a fragile recovery begun. It is hoped that with the new breeding pair, the population will continue to grow.
Philip Lo, senior conservation officer, told the BBC the swelling numbers could be seen as 'a piece of good news that could cheer up other dedicated conservation colleagues'.
The Hainan Gibbon is an ape only found on the forested Chinese island of the same name and in the 1970s the worldwide population was less than ten (pictured, location of the Chinese Hainan Island)
It is easy to identify a breeding pair, as a male is jet black, while females are a striking gold. They are also extremely vocal animals, producing loud calls to mark their territory
Populations of the tree-dwelling ape were decimated in the 20th century due to habitat loss as their home was cut down to make space for farms. Hunting and poaching was also a major driver of their decline
However, many other gibbon species are still heading towards oblivion. The Hainan Gibon is the only one out of 19 Gibbon species in the world to be showing a stable increase in number.
Conservationists are encouraged by the signs of recovery, but warn the animal is still at-risk, as verified by its formal classification as 'critically endangered' by the International Union for the Conservation of Nature (IUCN).
If the total number of Haunan Gibbons had surpass 50, the IUCN designation will likely be downgraded to 'endangered', according to Mr Lo.
In 2007, the apes were being forced to live in a six square mile patch of forest devoid of the juicy fruit — figs and lychee — that the apes prefer to eat.
Thousands of native trees were planted, conservationists patrolled the region and research was jump-started to learn more about the animals' ecology and behaviour.
Researchers claim the Earth is going through a 'man made' sixth mass extinction with the 'biological annihilation' of wildlife
The world has experienced five mass extinctions over the course of its history, and experts claim we are seeing another one happen right now.
A 2017 research paper claimed a 'biological annihilation' of wildlife in recent decades has triggered the sixth mass extinction and says the planet is heading towards a 'global crisis'.
Scientists warn humanity's voracious consumption and wanton destruction is to blame for the event, which is the first major extinction since the dinosaurs.
Two species of vertebrate, animals with a backbone, have gone extinct every year, on average, for the past century.
Currently around 41 per cent of amphibian species and more than a quarter of mammals are threatened with extinction.
There are an estimated 8.7 million plant and animal species on our planet and about 86 per cent of land species and 91 per cent of sea species remain undiscovered.
Of the ones we do know, 1,204 mammal, 1,469 bird, 1,215 reptile, 2,100 amphibian, and 2,386 fish species are considered threatened.
Also threatened are 1,414 insect, 2,187 mollusc, 732 crustacean, 237 coral, 12,505 plant, 33 mushroom, and six brown algae species.
More than 25,000 species of 91,523 assessed for the 2017 'Red List' update were classified as 'threatened'.
The number of invertebrates at risk has also peaked.
Scientists predict insects may go extinct within 100 years as a result of crippling population decline.
The dawn of the mass extinction coincides with the onset of the Anthropocene - the geological age defined by human activity being the dominant influence on climate and the environment.