Some troubling news today about humankind's closest living relatives.
A new report says 25 species of monkeys, langurs, lemurs, and gorillas are on the brink of extinction.
The report was done by the International Union for Conservation of Nature and was released at the United Nations' Convention on Biological Diversity being held in India.
"Once again, it shows that the world's primates are under increasing threat from human activities. Whilst we haven't lost any primate species yet during this century, some of them are in very dire straits," said Dr. Christoph Schwitzer, of the Bristol Conservation and Science Foundation - one of the groups involved in the study.
In fact, the world has not lost a single primate species to extinction in the 20th century or in this century. But that doesn't mean the situation isn't critical.
Overall, more than half of the world's 633 types of primates are in danger of becoming extinct.
That's because of human activity such as the burning and clearing of tropical forests, the hunting of primates for food and the illegal wildlife trade.
Among the 25 most endangered primates, six are from Madagascar off southeast Africa. Five more are from mainland Africa, five are from South America and nine are from Asia.
Lemurs are most at risk: 91% of the 103 species and subspecies are threatened with extinction.
Madagascar's rarest lemur - the northern sportive lemur - is dangerously close to being wiped out with just 19 left in the wild.
"Lemurs are now one of the world's most endangered groups of mammals, after more than three years of political crisis and a lack of effective enforcement in their home country, Madagascar," said Schwitzer.
"A similar crisis is happening in Southeast Asia, where trade in wildlife is bringing many primates very close to extinction."
Only one gorilla species is considered on the brink of extinction - the eastern gorilla from eastern Congo.
However, all of the great apes - gorillas, chimps, orangutans, and bonobos - are either endangered or critically endangered.
The report says global action is needed to protect these species from being gone forever. The authors say conservation efforts in some areas are starting to pay off, with several species of primates no longer listed as endangered.
Primates are incredibly important to the eco-system, as they play a key role in maintaining the world's tropical forests by spreading tree and plant seeds.
Not only that, but they've also become a big draw for eco-tourists, which is an important source of livelihood for many nearby communities.
Of course, one of the people who's led the fight to protect primates is Jane Goodall. She's been at it for the past 50 years.
One of her goals now is to teach the next generation to value primates the way she has. The Jane Goodall Institute recently launched a blend of coffee, ethically sourced from areas of Africa.
A portion of every package sold will go to the Institute, to help it protect chimps, and improve life for coffee workers, in Uganda and the Democratic Republic of Congo.
Goodall was in the red chair a few weeks ago.
Goodall now travels about 300 days a year, calling on the world to protect the environment and wildlife. This past weekend, she spoke at the University of Maryland. You can read about that here.
Andrew Westoll is another primatologist we've had on the show. He wrote a remarkable book called 'The Chimps of Fauna Sanctuary'.
It's about a family of traumatized chimpanzees - who underwent years of cruel medical experiments - and the remarkable woman who saved them.
In this clip, Westoll tells a fascinating story about a night when the chimps roamed free in the sanctuary.
And if you want a great family film about chimpanzees in the wild, check out 'Chimpanzee.'
It's about a little chimp named Oscar who finds himself alone in the African jungle until he's adopted by an older chimp who raises him like his own child.
Here's the trailer.
By the way, another report was released at the same conference - this one was about global urbanization.
That report called for urban planners to incorporate green spaces in cities as more and more people move into cities.
The world's total urban area is expected to triple between 2000 and 2030, while city populations are expected to double to around 4.9 billion.
The report says green areas in big cities help the environment by "filtering dust, absorbing carbon dioxide from the air and improving air quality."
The report also suggests that green space can help lower a city's temperature, thereby reducing the amount of energy used for air conditioning.
Other studies have suggested that an abundance of trees can help reduce the number of cases of childhood asthma and allergies.