Category: primates

Readers’ wildlife photos and video

February 9, 2026 • 8:30 am

Posting will be light today as I have three meetings/events to attend. I am supposed to be retired!

Those of you with photos please send them along, as I have about three more batches before Armageddon hits. Thank you!

Today we have the second batch of photos from Sri Lanka contributed by reader MichaelC—and one video (his earlier batch on the flora is here).  Michael’s captions and IDs are indented, and you can enlarge the photos by clicking on them.

Sri Lankan Fauna! 

Unlike the orchids and Angel’s Trumpets, which kindly stayed still for me, most of the animals did not. So few of my critter photos are well focused. Even so, some are interesting.

An Indian Elephant (Elephas maximus indicus) snorkeling its way across a lake! Right behind this fella were two cows and a young one, also snorkeling:

Here’s the big fella coming out of the lake….:

….to join a herd of some thirty other elephants. We were in an open vehicle on a tour of Wasgamuwa National Park. This is a close up showing a newborn calf. There were a number of Sri Lankan biologists there in other vehicles documenting the little one, which they said was only four days old:

These are all wild elephants who are accustomed to gawking tourists. Nevertheless, our guides were very stern about never leaving the vehicle. Elephants tolerate people, but they don’t like us. That’s by design. Sri Lankans value their elephants and don’t want to cull them in order to keep them from destroying crops. They do not kill elephants unless they become a threat to people. So farmers use what are essentially paint ball guns to shoot them. Stings like hell, but does no harm. The elephants learn to avoid people, but the process makes them cranky and unpredictable. Indeed, my soon-to-be-wife and I (and a bunch of other guests) were chased off a dinner set up on a beach in Yala National Park by a cranky bull elephant. The resort had “spotters” positioned around the resort watching for elephants. A familiar, bad-tempered bull decided he didn’t want any humans on his beach, so the spotters came running. 

This is a Brahminy Kite (Haliastur indus). They follow the herds and gobble up things they stir from the grass.

Two Many-lined Sun Skinks (Eutropis multifasciata) caught in flagrante delicto:

A Sri Lankan Wild Boar (Sus scrofa cristatus), a subspecies of the Indian Wild Boar (Sus scrofa):

Some sort of Agama, maybe the Ground Agama (Agama aculeata)?:

Chital or Sri Lankan Spotted deer (Axis axis ceylonensis):

A Snowy Egret (Egretta thula) going for a ride on a Water Buffalo (Bubalis bubalis):

A Red-wattled Lapwing (Vanellus indicus) standing in her nest:

Asian Green Bee-eater (Merops orientalis) the birds are welcome visitors to Sri Lankan, migrating in from India (I suppose) part of the year. They are very pretty and have a wonderfully beautiful song:

A Little Egret (Egretta garzetta) with a disappointed Mugger Crocodile (Crocodylus palustris). This was the last in a series of shots of the two. The croc tried to sneak up on the egret, but the bird saw him the whole time. It was hilarious because the croc thought it was being so stealthy but the bird just carried on fishing and was like; “dude, you know I can see you, right?”.:

Common Green Forest Lizard (Calotes calotes) displaying mating green:

These Hanuman langurs (Semnopithecus sp.?) are notorious thieves. But this guy was part of a small troop who completely ignored us:

Bengal monitor (Varanus bengalensis). This guy was more than a meter long!:

Lagniappe! A short video of immature bull elephants working out the pecking order. Or maybe just showing off. The young males spent a lot of time jousting like this. Surely it must be important behavior because otherwise, instead of spending their time and energy doing this, they could be eating and growing:

Chimps engage with pretend objects, suggesting they have imagination and can engage in pretense

February 6, 2026 • 10:30 am

Humans have the ability to do “secondary representations”: that is, to pretend that one object or action is actually different from a real one. This can also be called “pretense”. Examples are children’s “tea parties” in which they use empty pots and toy cups, pretending to drink from the empty cups while knowing they are empty. Then they can pour pretend tea into one of two cups, and when asked to drink will drink from the “pretend full” cup. Or they can have sword fights with sticks, pretending that the sticks are real weapons while knowing they are not.

Secondary representations of states that are only imagined start early (some experiments suggest at 15 months), and the ability to imagine things that haven’t happened, or aren’t real, surely underlie much of human behavior involving planning for the future or imagining what someone might be thinking.  The authors of a new paper in Science (see below) argue that no such abilities to “pretend” or have secondary representations are known from any species save humans. (I am not sure about this. As I recall some birds caching food are known to unhide it and re-cache it elsewhere if they see other birds looking on: something that seems like an ability represent another bird’s state of mind.)

And there is anecdotal evidence that chimps can do this.  For example, female chimps have been seen to hold and carry sticks as if they were their babies; this involves imagining that the stick is a real baby (that only females do this suggests sexually differentiated behavior).  Or if chimps have played with blocks, sometimes they’ve been observed to drag around imaginary strings of blocks.  This and other data suggest that some primates can have imaginative representations, but the existing data, say Bastos et al., don’t rule out other explanations.

They thus did three experiments on a single, human-acclimated male bonobo at a facility in Iowa. The bonobo, named Kanzi, was 43 years old and died the year after the experiment (no, he didn’t pretend to be dead!). Kanzi has his own Wikipedia page, which notes his abilities:

Kanzi is well known for his noteworthy cognitive abilities. He had a very well-documented linguistic understanding of the human language. He is believed to be the first non-human great ape to understand and comprehend spoken English. In addition, he was also heavily documented for his understanding and usage of symbols to communicate, usually through lexigrams and partial ASL. The vast amount of information that researchers gathered from Kanzi created a significant impact for the fields of linguistics and cognitive science. Kanzi’s behavior and abilities have been the topic of research published in scientific journals, as well as reports in popular media. He died in 2025, in Atlanta, Georgia.

Click below to go to the paper (pdf here), or you can read a summary of the study in the NYT, written by Alexa Robles-Gil, here (archived here)

Three experiments were involved, but the second was really a control for the first.

First, Kanzi was prepared for the pretense test by letting him learn about a real object: fruit juice that could be poured into glasses from a pitcher. In 18 trials, real juice was poured into one of two cups from a pitcher. Kanzi, who had been trained to point at what he wanted to have, was then asked, “Where’s  the juice?” He was successful in all trials.

Then the pretense experiment began. The same pouring was done, but from an empty pitcher into both of two empty cups.  Then one of the pretend-filled cups was poured back into the pitcher, so it would be pretend-empty while the other was pretend-full. Again, Kanzi was asked “Where’s the juice?”  In 50 trials, involving no reinforcement of any kind for making the correct choice, Kanzi chose the pretend-full cup 34 times and the pretend-empty cup 16 times, a highly significant deviation from an expectation of 50:50 under the null hypothesis. This showed that Kanzi could track where pretend juice was.

The second experiment used a cup of real juice next to an empty cup, and the empty cup was pretend-filled from an empty pitcher. Then Kanzi was asked, “Which one do you want?” Kanzi wanted the real juice in 14 out of 18 trials, again, a significant deviation from 50:50 under the null hypothesis. This showed that Kanzi didn’t simply believe that there was real juice in the empty cups in the first experiment, for he was able to distinguish real juice from pretend-poured juice.

The third experiment was like the second, except involving grapes. First, Kanzi was “trained to indicate the location of a real grape in one of two transparent jars after observing the experimenter sample a grape from a plastic container and place it into one of the jars and perform a control action on the other jar.” When asked to choose one jar to get the grape, he was successful in every one of 18 trials.

Then Kanzi was given pretend grapes to choose. From the paper;

In probe trials, the experimenter pretended to sample a grape from an empty container, then placed it inside one of the two jars, before repeating the same action on the other side. Then, one of the jars was pretend-emptied, and Kanzi was asked, “where’s the grape?” Kanzi succeeded at this conceptual replication even more quickly than in the first experiment. He correctly indicated the location of the remaining pretend grape above chance, in 31 out of 45 unreinforced probe trials

Again, Kanzi was highly successful at the juice and grape trials, able to recognize a pretend action of pouring and emptying juice, and determining which of two jars containing pretend-grapes had had the grape removed. In other words, he was playing tea party, and highly successfully.

This one chimp, then, was able to conceptualize pretend actions as real ones.

There are a number of possibilities not involving secondary representation that the authors say could be happening here. For example, apes like Kanzi who have been trained to recognize symbols to represent objects (as he was), might be better at communicating their wishes than are wild apes. Or symbol training could actually create the ability to do secondary representation. It’s hard to rule out these possibilities since to do such experiments an ape has to be “enculturated” by interaction with humans, and Kanzi was surely highly enculturated.

But if the authors are right that these experiments show that apes can have secondary representation, playing along with “pretense”, that opens up a world of possibilities of thinking about the cognitive abilities of apes (and other animals). The authors dwell on this at the end:

Secondary representations underlie many other complex cognitive capacities, such as imagining future possibilities (20) and mental state attribution (13). Our results may therefore help to interpret other bodies of data that have been hampered by an apparent logical problem (32). Finding that a bonobo can generate secondary representations in pretense contexts increases the likelihood that these representations are available for other cognitive functions. This finding reinforces growing evidence that apes track decoupled mental states, such as beliefs, rather than simply reading behavior (25, 28, 31). It also increases the likelihood that secondary representations could subserve future-oriented behavior (24, 35, 50–53), whose underlying representations have not yet been established.

In conclusion, our findings suggest that some nonhuman animals can generate secondary representations that are decoupled from reality, and that this capacity was likely within the cognitive potential of our last common ancestor with other apes, which lived 6 to 9 million years ago.

It is no surprise that our closest relative (along with chimps) could do this. As Darwin posited in 1871, our own behaviors and mental states evolved from those present in our common ancestors.

Kanzi died suddenly the year after the experiment, simply collapsing. He apparently suffered a heart attack, as he had a history of heart issues and had previously been obese. You can read about his other training in representing objects with keyboard symbols at the Wikipedia site.

From Wikipedia, here’s Kanzi in 2006 (he died in 2025):

William H. Calvin, PhD, CC BY-SA 4.0, via Wikimedia Commons

Readers’ wildlife photos

December 10, 2025 • 8:15 am

Hey, folks, we’re fast running out of photos. Please send yours in if you have good ones. Thanks!

Today we have pictures from two reserves in South Africa, sent in by Alex Skucas.  Alex’s captions and IDs are indented, and you can enlarge the photos by clicking on them.

These are from our summer (their winter) safari to Timbavati Private Reserve in South Africa.  Timbavati is adjacent to Kruger and some years ago they took down the fence between the two so that the animals could come and go freely.  We saw all of the Big Five on our first day.

 

Juvenile black rhinos playing at the watering hole.:

 

The whole family on their way to the watering hole:

Lion family nap time – two brothers and a sister.  They didn’t seem to care that we were just feet away in our vehicle:

 

And, of course, lots of African bush elephants.  They were everywhere – and doing quite a bit of damage to the ecosystem by knocking over trees.  There is an over-abundance of elephants in this area, and it is a concern for the parks:

 

These are a few pictures from a trip we took to Zimbabwe and Zambia this summer, right after spending time in Timbavati.  We had a special guest join us for lunch at Victoria Falls [JAC: a vervet monkey]

 

This leopard in Zambia was resting and had a fresh gash on his left flank, possibly from a fight with nearby baboons.  We were assured he would be fine:

 

Giraffe getting a drink.  Giraffes can only maintain this posture for a short time due to the increase in blood pressure on the brain:

 

An elephant walking over a Nile crocodile.  The elephant was taking a long slow walk along a berm and there was a croc in its path.  The elephant momentarily paused before stepping right over the croc – the croc never even flinched and kept sunning itself:

The elephant continued unfazed.  You can see the marks where it crossed through some deep water:

 

Elephants can swim using their snouts as a snorkel.  Here are two on either end of a calf, protecting it from crocs (and presumably the hippos too):

 

And the three safely emerging from the river:

Readers’ wildlife photos

November 14, 2025 • 8:20 am

Today’s photos come from reader Todd Martin, with a variety of shots taken in Taiwan. Todd’s captions are indented, and you can enlarge his photos by clicking on them.

My wife and I just returned from a trip to the Republic of China (aka Isle Formosa or more commonly Taiwan) and realized I had enough photos for another Readers Wildlife Photos post. Taiwan is a populous country, but thanks to the mountainous terrain (which covers about 70% of the island) there is quite a bit of natural beauty and opportunities for hiking (assuming one can bear the hot, humid climate).

These first two photos are Formosan rock macaques (Macaca cyclopis). They seem peaceful and coo softly to one another when eating, but don’t let that fool you. They can be quite aggressive and there are signs warning people not to interact with them, which I deemed to be pretty solid advice.

In the Alishan National Forest Recreation Area we climbed the many stairs found on the Tashan Trail to the summit of Mount Data only to find the peak (and its purported views) enveloped in a thick fog. Fortunately, there were quite a few of these Formosan Laughing Thrushes (Trochalopteron morrisonianum) there to greet us, which we dubbed our ‘consolation bird’:

On the way back down we were thrilled to encounter this beautiful male Mikado Pheasant (Syrmaticus mikado). The birds are considered endangered, but the good news is that their numbers have increased from about 5,000 in 1986 to 10,000 today:

I’m not much of a birder, so I rarely know what I’m looking at until I have a chance to look it up later so I referred to these birds as ‘skinny egrets’. In actuality, they are Eastern Cattle Egrets (Ardea coromanda) and were pretty common in Taiwan and we often saw them poking about grassy areas looking for insects:

One final bird is this (not very good cell phone photo) of a Black-crowned Night Heron (Nycticorax nycticorax). Their habitat is wetlands, but this sophisticated fellow was hanging out in front of the Taiwan National Museum.

I was pleased to get a photo of this Green Metalwing Damselfly (Neurobasis chinensis) because they’re pretty quick and don’t hold still for long. That is … until I got home and saw the full-sized image, which looks like something designed by H.R. Giger for a Ridley Scott movie:

This is a female Stag Beetle (I’m guessing Lucanus datunensis) that I only just avoided stepped on. Thank goodness for quick reflexes, I don’t think the resulting crunch would have been good for either of us:

As an island, Taiwan has a lot of coast to explore and on the south coast we happened upon this Green Sea Turtle (Chelonia mydas). I could see this one under the water but had to wait about 10 minutes for it to surface to get this (albeit mediocre) photo:

The following are some reasonably interesting plants we encountered.

Angel’s Trumpet (Brugmansia):

Flossflower (Ageratum houstonianum) an invasive species:

Blue Lotus (Nymphaea nouchali):

Ferns (Polypodiopsida, though I’m afraid I don’t know specifically which ones):

Some sort of Morning Glory (Ipomoea):

 

Finally … I’ve seen tandem bicycles and bicycles equipped with kid seats, but this is the first time I’ve seen one with a perch. These lovely Rosy-faced Lovebirds (Agapornis roseicollis) were out for a spin along the coast and seemed pretty pleased to be doing so.

Menopause in gorillas: a new study

October 23, 2025 • 10:45 am

If you think about it, you might realize that after an animal finishes reproducing, it should die, because genes that make you live on after you can no longer reproduce have no selective advantage: they are no better than genes that kill you off when you’ve had your last child. In principle, natural selection should keep you pumping out gametes and children until you die.  But in some species, namely ours, some of our ape relatives, and, curiously, some toothed whales like killer whales, females continue to live for considerable periods after their reproduction ends. We call that end “menopause”.  This leads to three questions:

a. Why do animals cease reproducing? That is, why don’t they continue to reproduce until they die?

b. Why in some cases do animals continue to live even after they cease reproducing?

c. Why don’t males undergo “manopause” in our species?

This new paper from PNAS (click title below to read, or find the pdf here) deals with the first two questions, but not with the third; and I’ll leave readers to ponder that one. The paper in fact, simply shows that in one population of mountain gorillas in Uganda, many females do show a form of menopause, living on for nearly a quarter of their adult lives as nonreproductives. While this phenomenon has been demonstrated in chimps, other studies of gorillas have not shown it. The authors posit that there may be different results in different wild populations of gorillas, though that’s hard to understand if you think the phenomenon involves natural selection. Why should such selection differ among populations of the same species? The hypotheses below don’t predict interpopulation variation.

Read on:

The first question above can be answered by realizing that menopause may be partly a cultural phenomenon. For the vast majority of our evolutionary history, humans probably died before the females stopped reproducing: probably between ages twenty and forty. There may have been no menopause in our species because nobody lived long enough to show it. And that may be one clue for why we show it now: any genes that cause women, at least, to lose reproductive ability when older were simply not expressed, and thus not selected against. This may also be the reason why earlier studies of chimps showed menopause: they were taken care of in zoos or reserves in a way that allowed them to live longer than they did during most of their evolutionary history.

Further, this population of gorillas, though living in a reserve, were not given special food or treatment (some were given vet care, but those were omitted from the study), and still showed not only menopause, but long lives after menopause. The “evolutionary history” phenomenon can’t easily explain that.  Nor can it explain postreproductive life in toothed whales—unless that was seen only in aquaria where they lived longer than they would have during much of their evolution, including now when living in the open ocean. (One would have to look at the studies to determine that.)

But regardless of the cause, one can say that one population of mountain gorillas under natural conditions—probably similar to those that obtained during most of their evolution—often show not only a cessation of reproduction but also considerable years of life beyond that. And the behavior of gorillas makes some of the evolutionary hypotheses for menopause seem unlikely.

Results.  This will be short. The authors studied 25 adult female mountain gorillas (Gorilla beringei beringei, one of two subspecies of the Eastern Gorilla) in Bwindi Impenetrable National Park in Uganda.  The females came from four groups, and their life histories were known, presumably through intense observation.  (Mountain gorillas hsve indeed been studied intensively, most famously by George Schaller and later by Dian Fossey (who was murdered during her studies.) The study populations are fairly easily habituated to human presence, which allows this study.

Here’s how they define “post-reproductive females” and how many of them showed menopause:

 According to a commonly used definition, “postreproductive females” are those who live past the age of their last reproduction for longer than the mean plus two SD of successful interbirth intervals (2). We calculated this value as 7.7 y [5.1  (2  1.3)] in our study population, suggesting that seven out of the 25 study females qualified as postreproductive. Six of these seven females have been conservatively estimated (based on the ages of genetically identified offspring, body condition and hair loss) to be older than 35 y old, which is the maximum age of observed reproduction (Figs. 1 and 2). All the seven postreproductive females exhibited a postreproductive lifespan of at least 10 y (Fig. 1), minimizing the possibility to be “mistakenly” classified as postreproductive. These females were not observed mating for an average of 7.4  5.8 y before they exit the study

And a summary:

Our study shows that wild Bwindi mountain gorillas can exhibit long postreproductive lifespans. Given that female gorillas rarely reach 50 y of age in the wild (6), the 10 postreproductive years lived by one third of the study females represents at least 25% of their adult lifespan (adults: 10 y old). More generally, the standardized population measure of PrR suggested that females spend 10% of their adult lifespan as postreproductive. Importantly, neither of the two methods we used to derive postreproductive lifespan can distinguish menopause from other causes of sterility, such as an increased fetal loss probability in old females. Nevertheless, the extensive duration of postreproductive lifespan, the reduced or lack of mating activity, and previous endocrine analyses of old females (8, 9) suggest that menopause is a highly plausible cause for the reproductive patterns we observed. The selective pressure(s) which might have favored the evolution of this trait in gorillas remain unclear.

Indeed; menopause remains a mystery in all species that show it. We have hypotheses but no substantive answers.

So the question arises of what, if any, selective pressures could have promoted female longevity beyond reproduction.  This assumes—which we don’t know—that postreproductive survival was an adaptation. If it was, and not just a “spandral” here are a few hypotheses. The bold headings are mine, and indented text is from the paper:

a. Reproductive conflict:

The “reproductive conflict hypothesis,” posits that old females cease reproduction to avoid competition for limited reproductive opportunities with young (related) individuals (12); e.g., their daughters or the mates of their sons]. Female gorillas disperse from their natal groups and often disperse again from groups where they have reproduced (13), meaning that they have low relatedness to their groupmates. Hence, the benefits of reproduction for female gorillas at an old age may be greater than that for chimpanzees or humans, where female local relatedness increases with age and females reproduce simultaneously with their offspring (12, 14).

Avoiding conflict with individuals is advantageous only if they’re related, for this would be a form of “kin selection”. Since gorillas’ dispersal take them away from their kin, that makes this hypothesis less likely but not completely unlikely.

b. Intergenerational help, one form of which is the “grandmother hypothesis”. 

Another relevant set of hypotheses, also relatively unlikely to apply to gorillas, posit that intergenerational help, and its positive influence in grandoffspring fitness, may drive the evolution of postreproductive lifespan through two not mutually exclusive evolutionary pathways [see also “grandmother hypothesis”; (1)]: by selecting for longer female lifespan to allow females overlap with grandoffspring and help them increase their fitness (e.g., by offering their ecological knowledge, or by defending them). . .

. . . The associated “mother hypothesis” (15) might have greater predictive power in gorillas. This hypothesis posits that old females cease reproduction to minimize energy expenditure or other reproductive costs, and maximize investment to existing offspring and their fitness. Consistent with this hypothesis, maternal presence, care, and support is critical even for adults in gorillas and other hominids (16).

This too is a form of kin selection (as is parental care), for genes that help you take care of your grand-apes, or your offspring when you’re old, will still be helping copies of those genes in their still-reproductive descendants.  This is feasible for taking care of offspring, but given the dispersal of female gorillas, the “grand-ape” hypothesis is less likely.

And here’s a nonadaptive hypothesis, but one that is popular:

c. Menopause is a nonadaptive byproduct of gorillas’ life history. 

A final hypothesis posits that postreproductive lifespan is a nonadaptive by-product of life-history patterns. Given that many wild animals die from predation, disease, or starvation, genes whose deleterious effects appear only in advanced ages, may not be purged (15). When “favorable” conditions allow individuals to survive at these ages, deleterious effects that prevent reproduction may appear (4, 11). Accordingly, greater food abundance and potentially lower predation pressure in comparison to the evolutionary history of chimpanzees, may allow Ngogo chimpanzees to live longer and exhibit menopause (4). Similarly, Bwindi gorillas currently do not face any predation risk from leopards, their main potential nonhuman predators,

A version of this hypothesis is that some genes have the effect of promoting reproduction early in life, but at the price of inhibiting reproduction later in life. Under many conditions, such “early reproducing genes” will be more adaptive than genes promoting later reproduction, because the former leave more copies of themselves earlier. (Those genes, for example, would be heavily favored in a growing population.). Thus senescence and menopause could simply be the result of the accumulation of adaptive “early-reproducing genes.”

Which, if any, of these hypotheses are right? We don’t really know for primates or toothed whales, and though there may be evidence for “senescing” genes in some laboratory species, I’m not aware of it.

The question remains why don’t male chimps, gorillas, and humans show “manopause”.  Some human males, for example, can father offspring even at the age of 80, but you’ll never find a woman reproducing at that age And we have no data from chimps or gorillas on males, at least as far as I know.

So, as always, “more work needs to be done”. But at least we now know that gorillas and chimps have menopause in females, which might make you a big hit if you bring it up at a cocktail party. And don’t forget to mention those toothed whales!

Readers’ wildlife photos

October 22, 2025 • 8:15 am

Today’s wi8ldlife photos came from Charles Dunlop, who notes that they were taken in Costa Rica in 2019.  I’ve indented his brief captions, and my own IDs are in brackets. Some of the animals are unidentified, so feel free to weigh in in the comments. You can enlarge the photos by clicking on them.

Violet sabrewing [Campylopterus hemileucurus]:

Scorpion under black light:

Snake seen on night walk in Monteverde:

Coati [Nasua sp.]:

Crested guan [Penelope purpurascens]:

Cherrie’s tanager [Ramphocelus passerinii costaricensis]:

Iguana [Iguana sp.]:

Capuchin monkey [Cebus sp.]:

Jesus Christ Lizard [Common basilisk, Basiliscus basiliscus]:

Agouti [Dasyprocta sp.]:

White-throated magpie-jay [Cyanocorax formosus]:

Howler monkey [Alouatta palliata]::

Readers’ wildlife photos

September 18, 2025 • 8:50 am

Reader Loretta Michaels sent two batches of photos she took recently in Borneo, and these are the penultimate batch we have. Today I’ll be showing her mammal photos, and in a while we’ll see her pictures of birds and reptiles.  Loretta’s ID’s and text are indented, and you can enlarge the pictures by clicking on them,

My husband and I just got back from Borneo, a remarkable place for wildlife viewing (once you get over your jetlag from the long journey there…).  Here’s a sampling of the mammal pics.  I’ll send the bird/reptile pics separately.

Bornean orangutan (Pongo pygmaeus) – An orangutan species endemic to the island of Borneo and the main point of the trip. (There’s another sub-species of orangutan found in Sumatra.) It belongs to the only genus of great apes native to Asia and is the largest of the three Pongo species. The most arboreal of the great apes, orangutans spend most of their time in trees. They have proportionally long arms and short legs, and have reddish-brown hair covering their bodies. Adult males weigh about 75 kg (165 lb), while females weigh about 37 kg (82 lb). Dominant adult males develop distinctive cheek pads or flanges and make long calls that attract females and intimidate rivals; younger subordinate males do not and more resemble adult females:

Orangutans are the most solitary of the great apes: social bonds occur primarily between mothers and their dependent offspring, who spend up to 10 years with their mother, the longest time of all the apes. They can live over 30 years, both in the wild and in captivity.  These guys are considered the most intelligent of all the great apes, right after humans, and the stories about their many escapes from captivity are hilarious.  While we saw many orangutans in the wild, it was hard to get good pics as they were often half hidden in the foliage.  Some of these pics here were taken at the nearby orangutan sanctuary, which rehabilitates them and releases them.  Many of them come and go from the sanctuary grounds freely.  One mama that was released showed up outside our cabin, with her wild-born baby in tow.

Crab-eating Macaque (Macaca fascicularis) – Also known as the Long Tailed Macaque. Sadly,  it’s the most traded primate species, the most culled primate species, the most persecuted primate species and also the most popular species used in scientific research:

Pig-tailed Macaque (Macaca nemestrina) – Another of the many monkeys found here.  These large groups often consist of both types of macaques:

Sun Bear (Helarctos malayanus euryspilus) – The smallest bear species in the world, native to the tropical forests of Borneo, usually found in trees. They’re known locally as “beruang bada,” or honey bear, due to their fondness for honey.  It gets its name from its characteristic orange to cream-coloured chest patch:

It’s very elusive and hard to photograph, so this pic was taken at the Borneo Sun Bear Conservation Center, which is desperately trying to save the species.  Sadly it faces huge threats to its natural habitat, including mass deforestation, habitat destruction and illegal hunting and poaching across Borneo.  This particular female was stolen as a baby and kept in a cage as part of a roadside zoo.  By the time she was rescued she was so traumatized that she just paces in circles at this point.  (I’ve attached a pic of a display they’ve got at the center, showing the relative sizes of all the world’s bears. [JAC: see last picture below])

Maroon Leaf Monkeys (Presbytis rubicunda) – Also known as Maroon langurs or Red Leaf Monkeys:

Proboscis monkey or long-nosed monkey (Nasalis larvatus) – Distinctive arboreal monkey of riverside and mangrove forests. We saw lots of these guys, but mostly females.  The males, which are solitary and harder to spot, & have the much larger and more pronounced noses:

Prevost’s squirrel (Callosciurus prevostii) – Also known as the Asian tri-colored squirrel:

Added a pic of the dominant male at the orangutan sanctuary.  They say he’s a gentle giant, who unusually took under his wing a juvenile female when he first arrived, which they’d not seen before:

Loretta sent a bear size comparison picture. The sun bear is the smallest: