His photographs, especially those of monkeys, showcase micro-expressions that look like the kind we're used to seeing on other humans. Hilarious close-up portraits of some of the world's most unusual primates show their uncanny resemblance to humans.

Wanna hang? A black crested macaque getting ready to get some fun out of life. These charming and smart monkey species greet by smiling. Sulawesi, Indonesia. Crested black macaques are found only in Indonesia, restricted to the northeastern-most peninsula of Sulawesi island (formerly known as Celebes) along the Onggak Dumoga River and the megalithic Mount Padang, and to Sulawesi's neighboring islands of Pulau Manadotua and Pulau Talise. Historically, these Old World monkeys had also lived on the island of Pulau Lembeh, but they have since been eradicated. A secondary population, introduced by humans in 1867, lives 345 miles from Sulawesi on Pulau Bacan, in Indonesia's Maluki islands.

Proboscis monkey (Nasalis larvatus): Proboscis monkey bachelor with a perfectly peaceful expression on his face. The proboscis monkey is a large primate endemic to the island of Borneo. It is named after the long, hanging nose present in males and spends most of its time living in the trees near mangrove forests or jungle streams. It is also known as the long-nosed monkey and locally as the bekantan. Due to the threat of deforestation in its tropical rainforest habitat, populations of the species are in decline and it is listed as Endangered on the IUCN Red List.

The Zen Monkey: The rare red-shanked douc of Vietnam, one of the world's most colorful monkeys, with closed eyes showing its light blue eye shadow. Red-shanked Doucs are diurnal and arboreal, spending their days among the treetops in mixed sex social groups of varying sizes. They are very rarely seen on the ground. The doucs sleep in large, carefully selected trees with thick canopies, which are entered at dusk and are not exited until dawn. Their diet consists primarily of small, tender leaves but they also eat flowers, fruits, buds and seeds. The breeding season takes place from February to June, with a single infant born after a gestation period of around 210 days.

Mandrill in the mood: "Several times during the almost half an hour he sat in front of me he would make this curious facial expression, a crooked smile and twisting the tongue. Normally you would think of showing teeth as a threat, but a mandrill researcher has told me that this particular display is meant to show friendly intentions. He definitely did appear friendly. From the wild in Gabon."

On Fire: Black-crested macaque male showing teeth. Despite the impressive canines the monkey feeds mostly on fruits and invertebrates. It lives in troops that can grow to more than 100 individuals. Sulawesi, Indonesia.

The golden snub-nosed monkey from the mountains of Western China is one of the monkeys in the world that live in the socially most advanced societies. They congregate in troops of up to more than 400 strong and each member knows many of the other individuals. This takes a lot of brainpower – the golden monkey has the biggest brain of all the colobine monkeys – plus spending many hours watching each other. Like this young male is doing, sticking his tongue out and having a focused look on his face. Qinling Mountains, Shaanxi.

The Mark Of Power: Gelada male with its characteristic hourglass-shaped chest mark that is bright red in alpha males like this one and pink in bachelors. Red is the color symbolizing power. Simien Mountains National Park, Ethiopia.

Only one monkey troop in the world frequents a hot spring, the one at Jigokudani in the cold mountains of Japan. Here two mothers and their young. Dominant females spend more time at the spa than subordinate females, so getting to use the thermal pool is a privilege. Infants of dominant females get to bath more than children of females further down the social ladder. Males that migrate into the Jigokudani troop as adults never acquire the habit of bathing in the hot spring. It is a habit you only learn as a kid.

Baby baboon posing for a portrait. Buffalo Springs, Kenya. Baboons are some of the most identifiable of the monkey world. They have tufts of hair on either side of their faces and large, hairless bottoms that can turn red. These old-world monkeys also do not have prehensile tails like some other monkeys, which means they don't use their tail like a hand. Baboons are only found in a very specific area of the world: Africa and Arabia. Four species, the chacma, olive, yellow and Guinea, live in the savannas. Others live in other semi-arid habitats, though some baboons can sometimes be found in tropical forests. The Hamadryas baboon lives in the hills along the Red Sea.

Baby Yeti: "Four-months old Yunnan snub-nosed monkey, the highest-dwelling monkey species in the world. It lives in the mountains in up to 4,700 meters where the average temperature is below zero for four months of the year and where the thick-furred creature can be seen walking through the snow. Baima Snow Mountain National Nature Reserve, Yunnan, China."