Helen Mylne

@helephantmylne

How long do monkeys live? 🐒 Turns out we don't really know! Postdoc in Centre for Research in Animal Behaviour at UoExeter modelling primate lifespans. Also elephant social network analyst 🐘 running entirely on sugar and a love of African wildlife 🌍

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Helen Mylne@helephantmylne· 25d

Primate Profiles #61: Southern Patas Monkey Patas are good at avoiding predators. They can move at 55km/h & spend 40% of the time in trees. They move sleeping tree each night, sleep spread out, & communicate with postures & facial expressions that can't be overheard. Image: palmoildetectives.com

Female Patas Monkey and baby sat in the top of a bush with morning/evening light from behind. They are predominantly gingery, with a paler front and white cheek fur. They have a dark muzzle and black rings around their eyes, but a white spot on the nose.

Helen Mylne@helephantmylne· 26d

Primate Profile #60: Nepal Sacred Langur Females mate year-round but give birth in late winter. Even already-pregnant females will mate, thought to confuse paternity to avoid infanticide. Dominant males will chase subordinates who attempt to mate (not always successfully). Image: W Goh (iNat.org)

2 female langurs sat holding their babies on top of a fence. Both have their bodies angled towards the camera but the right hand one is looking back over her shoulder so her face is hidden. The left one is looking straight at the camera.

While these langurs are not always very shaggy, these ones have very thick winter coats, making them look twice as thickset as a langur normally does. Their fur is grey all over, but a darker shade on the back and outside of the limbs than on the front and inside. The fur around the face is very pale and long, making their faces look very small in comparison to their heads. they have black faces. The babies have very similar appearance to the adults.

Helen Mylne@helephantmylne· 27d

Primate Profile #59: Mona Guenon These monkeys have a very varied diet from fruits & seeds to invertebrates, eggs & small lizards/birds. They crack open hard seedpods by hitting them on tree branches. They have large cheek pouches to store food for eating somewhere safer. Image: M Barth (iNat.org)

Mona monkey sat on a branch facing the camera.

These monkeys have a very distinctive colour patterning. Their backs are chestnut brown; their sides and the dorsal sides of their legs are black; and their chest, stomach, and the ventral side of their legs are white. The skin of their hands, feet and around the eyes is black, while the skin of their muzzle is pink. They have black ears, white cheeks and throat, and a grey cap. Their tails are long, slender, and completely black, but the tail is not visible in this image. They have a pair of white oval patches at the base of the tail which are unique to mona monkeys.

Helen Mylne@helephantmylne· 28d

Primate Profile #58: Silvered Lutung Looking like tiny teletubbies, baby langurs are a strikingly different colour to adults. Allomothering is common, with adults apparently drawn to the bright-coloured infant. Interest in babies decreases once their fur fades to grey. Image: K Shuck (iNat.org)

Mother and baby silvered langur. The mother is grey all over, with long fur that is darker at the base and pale at the tips, giving the silvered appearance overall. They have a tall crest on their heads, making their heads look triangular. The facial skin is black with dark brown eyes. They have long slender tails. The baby is a similar shape, but with a rounder head, and has bright orange fur instead of grey, a white beard, pink facial skin, and very large ears. The baby's tail is out of sight, but they are somewhat striped.

Helen Mylne@helephantmylne· 29d

Primate Profile #57: Chacoan Titi These monkeys are highly adaptable to their environment, inhabiting both very dry forests and swamplands. Titi monkeys rub their bodies with chewed leaves, which is thought to help ward off insects. Image: @myworldofbirdphotography (iNat.org)

Two Titi monkeys in a tree, looking at the camera. Chacoan titis are a pale buff colour, with thick fur and long tails. Their faces appear small relative to their heads, thanks to the thick fur making their eyes look very round and close together, and with small muzzles and mouths.

Helen Mylne@helephantmylne· Jul 9

Primate Profiles #56: White-cheeked macaque Only described 11yrs ago & found only in a tiny area of southeast Tibet, very little is known about these monkeys. They and their habitat are threatened by illegal hunting and large scale hydropower development. Image: C Li (DOI: 10.1002/ajp.22394)

Female white-cheeked macaque sat on a log, taken from a camera trp image. She is sitting directly facing the camera. As their name suggests, she has white cheeks and a pale head, whereas the rest of her is an olive brown colour. The skin around her eyes is dark pink. Their ears are very small, and hidden amongst the fur so they are difficult to discern from the rest of the head.

Helen Mylne@helephantmylne· Jul 6

Primate Profile #55: Tantalus Monkey Like many social species, tantalus use vocal alarm calls to warn other group members of predators. A lone dog will illicit these alarms, but a dog and human together will not. This is thought to be adaptive to avoid human hunters. Image: N Fermont (iNat.org)

2 juvenile tantalus monkeys on grass. The left hand monkey sitting down with legs stretched out in front, holding onto the tail of the right had monkey, which is trying to walk away.

These monkeys have greyish brown agouti fur on their backs, with grey undercoat visible on the legs, rear and tail. Their faces are black, with a white surrounding.

Helen Mylne@helephantmylne· Jul 3

Primate profiles #54: Humboldt's Night Monkey Unsurprisingly, owl monkeys have great night vision, with more light-sensing cells than other primates. They have a large auditory cortex in the brain for catching insects and excellent smell for sniffing fruit in the dark. Image: @daniesser (iNat.org)

2 night monkeys in a hole in a tree. the one in front is mostly hiding the one behind.

Night monkeys have round heads and extremely large eyes, providing excellent night vision. This species has mottled grey fur on the back, and yellow on the front. They have small ears, and large white eyebrows, with 3 black lines running up their foreheads. Their fingers are very long to help with an arboreal lifestyle.

Helen Mylne@helephantmylne· Jul 2

Primate Profile #53: Udzungwa Red Colobus Males remain with their natal group but females disperse at maturity. Suckling is usually restricted to the current infant, but older (inc. adult) males sometimes suckle, suggesting long term investment in sons. Image: @lesbectrotters (iNat.org)

Family of Udzungwa Red Colobus sat on the ground. There are 2 adults, with the left-hand monkey holding a baby and eating grass.

These monkeys have dark grey backs, and the dorsal side of their limbs and tails are also dark grey. The ventral side of their limbs and their chests are white. They also have white cheeks, and a very distinctive orange cap that covers their whole head. The baby's dur is more dappled, with white streaks in its back, and a much darker brown cap.

Helen Mylne@helephantmylne· Jul 1

Primate Profiles #52: Sierra de Perijá White-fronted Capuchin Capuchin monkeys (and cappuccino coffees!) were named after the "Capuchin friars": a group of Italian monks who always wore dark brown hooded robes, like the dark cap on the monkeys' heads. Image: S Nash (conservationbridges.org)

Illustration of a Sierra de Perijá white-fronted capuchin walking on all hours with tail curled around behind it. These monkeys are described as being cinnamon brown on most of the body, but with darker legs and a white face and shoulders (reference: All the World's Primates, 2016, edited by Noel Rowe and Marc Myers). The tail is darker on the dorsal side and buffy on the ventral side (reference: All the World's Primates, 2016, edited by Noel Rowe and Marc Myers).

Helen Mylne@helephantmylne· Jun 30

Primate Profiles #51: Putty-nosed monkey Males are usually at the group edge, rarely interacting with females and offspring. When threatened, the male takes the lead and mobs the predator to allow females to escape. They group with other guenons to reduce predation. Image: @photokeen (iNat.org)

Mother and baby putty-nosed guenon on a tree branch, in front of a background of leaves. They are sat facing the camera, with the baby about to walk off, and their tails hanging down.

These monkeys are very dark grey (appearing almost black in this image) with a slightly paler head. They have a characteristic large white triangular nose. Their heads are very round. Their tails are significantly longer than their bodies.

Helen Mylne@helephantmylne· Jun 29

Primate Profiles #50: Black-tailed marmoset Parents carry infants until just 2 weeks old, after which older siblings take over. By 8 weeks old, infants spend 90% of their time moving independently. Marmoset families sleep in holes in trees and cacti 🌵 Image: W Teixeira Florentino (iNat.org)

Adult black-tailed marmoset crouched on the side of a tree. It has it's mouth open suggesting the photo was taken while the individual was vocalising.

These monkeys are generally quite pale, besides their dark brown rump and long black tail (tail out of sight in this picture). The back and hind legs are pale brown. The crown of the head, ears and face are grey, but with a pink splotch on the nose. The rest of their fur is very pale grey, including along the tops of the hips and back legs, creating two lines of off-white that run along the sides of the back.

Helen Mylne@helephantmylne· Jun 26

Primate Profiles #49: Guianan Red Howler The only record of "tool use" by these monkeys (according to the book I'm currently using) is an adult male hitting a sloth with a large stick. A monkey with a big brain, but maybe questionable morals? 🐒 Image: @fernandofariasbirding (iNat.org)

Red howler monkey walking along a branch with tail in the air. These monkeys are reddish-chestnut all over, with grey facial skin. Their tails are long and prehensile. They have a large throat pouch which helps with their very loud howling calls.

Helen Mylne@helephantmylne· Jun 25

Primate Profiles #48: Bolivian Squirrel Monkey While fruit makes up ~90% of their diet, these little cuties are also insectivorous, famed for their ability to snatch flying insects from the air. Although rare, they occasionally share their food with other group members. Image: L Stevens (iNat.org)

Squirrel monkey perched on a branch.

These monkeys are bright yellow across most of their body, with particularly vibrant forelimbs. Also known as the black-capped squirrel monkey, they have a fully black head and grey chin, and a black tip to their long slender tails. Their ears are large white triangles sticking almost sideways out of their heads. They have a grey muzzle, and their facial skin is pink, making their round black eyes stand out.

Helen Mylne@helephantmylne· Jun 24

Primate Profiles #47: White-footed tamarin Despite their tiny size (weighing only 460g, with length 23-25cm), white-footed tamarins have a home range up to 97 hectares, requiring them to spend about 56% of their time travelling in order to get around it! Image: C Rangel (iNat.org)

White-footed tamarin on a branch. They are predominantly brown, but wihh white forearms and hands, giving them their name. Their heads are grey, with a white crest.

Helen Mylne@helephantmylne· Jun 23

Primate Profile #46: Red-bellied monkey It seems red-bellied guenons quite like other species! It is believed that they will sometimes follow the calls of hornbills to find the best fruit trees, and will group with other monkey species for improved predator protection. Image: @lauramhy (iNat.org)

Female red-bellied monkey sat on a horizontal bamboo pole, facing the camera with a long thin tail hanging down.

These monkeys have dark grey forelimbs, backs and heads, fading to paler grey towards the rump, hind limbs and tail. Their chest and stomach are a rich red-chestnut colour. Also known as the white-throated monkey, they have a very heavy ruff of thick white fur around their chin and throat.

Helen Mylne@helephantmylne· Jun 23

It takes skill to get this histogram of R-hat values from a single model 😎

Photo of histogram in Rstudio. No values are below 1.5, and the vast majority are over 100, with some over 2000. A healthy model should have nothing above 1.05.

Helen Mylne@helephantmylne· Jun 22

I wanted a full-family picture for the main post, but couldn't resist sharing this absolute gem from @bcmyrtlau on iNaturalist.org of a male Golden-faced saki enjoying his fruity lunch 🐒🥭

Male golden-faced saki monkey eating a piece of fruit. He is looking straight down the camera, looking very surprised by the photographer, with his mouth fully open showing the fruit hanging out of it

Helen Mylne@helephantmylne· Jun 22

Primate Profile #45: Golden-faced Saki Little is known about these monkeys, but it is believed that they have different responses to different predators: for large threats, they will silently slip away into the trees, whereas they will mob smaller predators as a group. Image: F Hayes (iNat.org)

3 golden-faced saki monkeys in the fork of a tree. The male is on the left and slightly underneath the female. The female is on the right and has the baby clinging to her back, looking over her shoulder. All 3 are facing the camera, but only the female is looking directly at it.

The male golden-faced saki monkey has sleek black fur everywhere except for their namesake golden face, which is shorter and frames their face inside two bean-shapes. They have a white moustache over their mouth.

The female golden-faced saki monkey lacks the golden face, and is instead mottled brown all over, except for shorter, more organey fur on her chest. The baby matches the mother.

Both males and females have very thick non-prehensile tails, but these are not visible in the image. Their fingers and toes are extremely long to help with climbing.

Helen Mylne@helephantmylne· Jun 19

Primate Profile #44: Hatinh Langur Living in the trees during the day, at night these monkeys sleep in sheltered holes in limestone cliff faces. They will use the same holes for many years, and don't share with other langurs except their own young offspring. Image: Endangered Primate Rescue Center

Hatinh Langur sat in a tree, looking towards the camera with long tail hanging down. These monkeys have a shiny black coat all over, except for a white chin strap that runs around the outside of the face. They have large ears, and large brown eyes. They have a long hair on top of their head, ending in an upward crest. Their limbs are long and slender.

Helen Mylne@helephantmylne· Jun 18

Primate Profile #43: Red-eared guenon Red-eared guenons have awesome faces! They use the bright red nose and facial fur tufts to recognise conspecifics from other monkeys. They also have cheek pouches for food storage that are just as big as their stomachs! 🐒 Image: A Ohanyan (iNat.org)

Red-eared guenon looking down at the camera from a thin branch. Their bodies are dappled grey, with a strikingly bright red long tail. Their faces are very distinctive, with a bright red triangular nose, large black eyes, and small red-tufted ears. They have large tufts of white cheek fur that stick straight outwards like very unkempt sideburns.

Helen Mylne@helephantmylne· Jun 17

Primate Profile #42: Red-bellied Titi While Titis do not display strong social preferences within their groups, they are territorial against out-group monkeys. They have a scent gland in their chest which they rub against trees, thought to be for warning off other titis. Image: N Wisnik (iNat.org)

2 red-bellied titis in a tree. Both are looking at the camera, but only the left hand monkey has the body angled facing the camera too.

These monkeys have pale mottled brown fur on their backs, and small black faces. Their chest, belly and bushy chin fur are, in contrast, bright orange . They have long tails and move quadrupedally.

Helen Mylne@helephantmylne· Jun 16

Primate Profile #41: Miss Waldron's Red Colobus Miss Waldron worked with the British Museum collector who named this species in 1933. The last confirmed sighting was 1978, but some 2001 evidence for a tiny remnant population provides a sliver of hope ⛅ Image: S Nash in McGraw 2005 Int J Primatol

Drawing of Miss Waldron's Red Colobus by Stephen Nash of Conservation International, drawn for McGraw 2005 paper in International Journal of Primatology ("Update on the Search for Miss Waldron's Red Colobus Monkey"). No photographs of this monkey alive are available.

This monkey has a black back and tail, with a tan coloured chest, stomach, legs and fur around the face. The face skin is grey, and it has small ears. The monkey is depicted walking quadrupedally.

Helen Mylne@helephantmylne· Jun 12

Primate Profile #40: Pileated Gibbon "Pileated" means capped, referring to the black cap on the otherwise-pale-furred-female's head. The male is entirely black. They can swing at up to 35mph through the canopy; on the ground they keep their arms above their head to walk! Image: @ayuwat (iNat.org)

Female pileated gibbon in a tree, hanging from her left hand. The female gibbon has pale sandy fur all on the head, back and limbs, but is black on the chest and stomach. Their skin is black, also giving them black hands, feet and faces. They have a white eyebrow across the top of their face. This female also has a baby with her, though it is not visible in the image.

Helen Mylne@helephantmylne· Jun 10

Primate Profile #39: Arunachal macaque There are some questions as to whether these macaques are a species in their own right or a subspecies of Assamese macaque. They inhabit India's Arunachal Pradesh region, on the border with Bhutan, at the foot of the Himalayas. Image: K Mazumdar (iNat.org)

Arunachal macaque balanced on all 4s across low branches of a tree. It is quite heavy set, so I believe it to be a male, but I'm not certain. The tail is sticking straight up.

The Arunachal macaque is brown all over, but more yellowish in the front half than the back, and with a pale chest. Their fur is thick, especially around the hind quarters. The tail is short.

Helen Mylne@helephantmylne· Jun 9

Primate Profile #38: Brumback's Night Monkey These nocturnal monkeys like sleeping in tree hollows during the day. At night, despite exceptional night vision, they stay close to sleeping sites on new moons when it's darkest and roam further under full moons. Image: T Nascimento de Melo (iNat.org)

A family of night monkeys peering down at the camera from bamboo branches. It has apparently been raining as their fur appears wet.

These monkeys have dense grey fur with long dark tails, and pale chests and bellies. They have furred faces except for the nose which is black skinned whereas their feet skin is pink. Like other night monkeys, they have large very round eyes which take most of their face. The facial fur is mostly pale yellow, but they have a black line up either side of their face that lines up with their corners of their mouth, and a black triangle down the middle of their forehead.

Helen Mylne@helephantmylne· Jun 8

Primate Profile #37: White-cheeked spider monkey Found in the middle of the Amazon basin, these spider monkeys live in large fission-fusion groups of 20-30 members, with subgroups of 2-4. This likely reduces foraging competition while still providing predator protection. Image: R Hoyer (iNat.org)

3 spider monkeys in a tree: 2 adults and an infant. Both adults are looking straight at the camera with apparently very shocked expressions. The left hand monkey is holding the infant.

These monkeys are black all over, except for the face which has pink skin and white fur on the forehead, cheeks and chin. They have long limbs for swinging through trees, and a prehensile tail that acts like an extra limb for grasping the trees.

Helen Mylne@helephantmylne· Jun 4

Primate Profile #36: Grays bald-faced Saki Despite their rather un-aerodynamic appearance, these monkeys are very agile among the treetops, able to leap 9m between branches. With a body size of ~40cm, this is 20-25 times their own body length! Image: P Faucher (iNat.org)

Grays bald-faced Saki lying on a tree branch, looking down at the camera with tail hanging down.

Since all Saki monkeys have a bald face, I'm not sure why these are specifically called "bald-faced". Their face is dark grey or black, and males can have quite large skin folds that aid in communication. The money's body is covered in a very thick layer of grey fur. Their tail is non-prehensile, and is the same length as their body, and almost as thick/wide as their body.

Helen Mylne@helephantmylne· Jun 3

Primate Profile #35: Collared Titi Titis are monogamous, with the adult male leading his family to feeding spots. They eat predominantly fruit, but if they pick up invertebrates they will eat them too. Lactating females eat the most inverts to get extra protein. Image: @juanrivasflorez (iNat.org)

Collared Titi monkey sitting facing the camera on a branch. It is a front view, only showing the face, torso and front limbs. The back limbs and tail are out of sight.

Collared Titis have thick dark reddish fur all over, with pale grey hands. Their name comes from the yellowish white collar that runs across the front of the body, which looks like a heavy necklace. Their face is grey, with a slightly paler muzzle and cheeks. Their eyes are brown.

Helen Mylne@helephantmylne· Jun 1

Primate Profile #34: Amazonian Black Howler As humans, we have opposable thumbs (we can touch the tip to each finger on the same hand) to help us grasp things. Howler monkeys have an additional opposable finger, along with a prehensile tail, for extra grasping abilities. Image: L Mercon (iNat.org)