23.3a – The Tarsier

Eyes on the prize. (Philippine Tarsier photo by Kok Leng Yeo)

If you break the primate tree into its two most basic divisions, all of the primates we’ve looked at so far — the lemurs, the loris, and the galago — belong to one group, and all of the primates still to come belong to the other. That former group, with the lemurs and such, is called strepsirrhine, and they are the wet-nosed primates. All of the others are in a group called haplorhine, and they are the dry-nosed primates.

There are a few other differences between them besides the dampness of their noses. The lemur group, as with most mammals, can make its own Vitamin C within its body, for example, which means they have no need to include citrus fruit or some other source in their diet; but the dry-nosed primates, which includes humans, lack this ability. To make up for it, the dry-nosed primates have much larger brains in proportion to their bodies.

The divide between these two groups took place approximately 63 million years ago. The first type of animal to separate from the rest of the dry-nosed primates — at least among those that survive today — were the tarsiers. In fact, they are such an old type of dry-nosed primate that even today some scientists debate which of the two groups they belong to.

But what is a tarsier? There are about ten species of tarsier, give or take a few we haven’t fully settled on yet, and they are small, strange-looking primates that look either very cute or nightmarishly alien, depending on your frame of mind.

The reason for this is their enormous eyes. I don’t want you to think I’m being hyperbolic when I say “enormous”. In absolute terms, certainly, a small monkey can only have eyes that are so big, but the tarsier stretches the bounds of relativity. Each of its eyes — not both together, but each separate — is as big as the animal’s brain. These are the largest eyes relative to body size in the entire mammal world. They look like tiny, big-eyed gremlins.

But you can’t judge a book by its cover, I can hear you saying. Just because it looks a little strange doesn’t mean it’s anything to be afraid of, right? It’s basically a tiny monkey, isn’t it? And tiny monkeys are cute and curious and wonderful, aren’t they?

… aren’t they? (Philippine Tarsier photo by Serafin “Jun” Ramos, Jr)

The first thing to remember about a tarsier is that no, it is not a monkey at all. It is an early, primitive form of the type of primate that eventually produced monkeys. One of the key differences, besides the outward appearance, is that the tarsiers are the only one hundred percent carnivorous primates alive in the world today. They don’t seek out fruit or vegetable matter. They eat nothing but the crunchy, squirming flesh of other living beings, including snakes, bats, birds, and lots of insects. Which I suppose means we’re back to them being essentially gremlins.

But in truth they are shy creatures, and certainly not dangerous. They’re nocturnal and live in and around the jungle islands of southeast Asia, such as the Philippines, Indonesia, and Borneo. Many of them are threatened or endangered due to habitat loss, human hunting, and predation by feral cats.

Sometimes they are kept as pets by well-meaning humans. Keeping a wild animal as a pet is almost never a good idea, but with the tarsier it’s an even worse plan. The tarsier is one of the rare animals that does significantly worse in captivity than it does living in the wild. In the wild, with an abundant food supply and a thick jungle in which to move around, a tarsier can expect to live for 24 years. In captivity, they last only 12 years at most, and can die as young as two years old. In human terms, this is the equivalent of taking a person who can expect to live to the age of 72 and placing him in an environment where he may fade away and die by the age of 6. That’s a poor thing to do to an animal, no matter how cute they look.

Some tarsiers are even known to commit suicide in captivity. They don’t actually kill themselves on purpose, but the stress of lights, unfamiliar noises, and human handling can seriously frighten a shy tarsier, and they will sometimes react to this stress by smacking their own heads against objects in their enclosure. Since they have fairly thin skulls, this can cause death.

Fortunately it’s illegal to sell or trade many types of tarsiers. Conservation efforts in some countries seek to establish safe refuges for the animals, but their future remains uncertain.

Tarsier distribution

Tarsier distribution

23.2b – The Galago

One in the hand is worth two in the bush. (Brown greater galago photo by buecherfresser)

Something in the dark jungle is crying, and it sounds an awful lot like a human baby.

If you’ve never heard of a galago (pronounced guh-LAY-go), don’t despair. Most people don’t know these animals by their official name, but some people have heard the more common term — bushbabies.

Along with lemurs and lorisids, galagos are one of the few remaining primitive primates in the world today. Primitive in this sense means that they are an older type of primate that developed before more modern forms, such as monkeys and apes. But while the lemurs have constrained themselves to Madagascar, and while the lorisids are slow and dropping in number, the galagos are living strong in Africa.

Also known as nagapies, which means “little night monkeys”, galagos are found all over central and southern Africa. There are about twenty different species, all of them nocturnal. It’s believed that the galagos evolved to be nocturnal so that they did not have to compete directly with the faster, more modern monkeys, who do their business in daylight.

But the galagos are no slouches, no slow-moving lorisids. They are quick on their feet and have long tails to give them balance as they jump through the trees. They have strong night vision, good hearing, and are so nimble they can catch flying insects out of the air. Their cries are said to resemble those of a human baby, an unnerving prospect in the jungle at night.

In addition to their night vision, galagos use urine, of all things, to help them scramble through the trees in the darkness. A galago that moves through the trees will mark its path with urine on the branches, and other galagos can smell this so acutely that they can jump right onto the branch even if they can’t see it. Imagine a world where humans marked important things, such as doorways, their vehicles, and favorite restaurants, with urine so they could find them again. On second thought, please don’t imagine that.

“That’s a nice couch. But I’ll tell you what. I’ve been drinking water all day, and I know how to make that couch even nicer.” (Senegal bushbaby photo by OpenCage)

A galago is also a fantastic jumper. It has very strong, elastic legs, and scientists figure that a galago is, proportionally, at least six times better at jumping than a frog. These animals are tiny, but they can jump six feet straight in the air. Don’t give one guff; it could jump straight for your nose.

The social life of a galago revolves around the females. Females control family groups consisting of themselves, their offspring, and sometimes other female relatives, maintaining a specific territory. Males are forced to leave these groups when they grow up. The strongest males form their own territories that overlap female territories, but they are not allowed to live with the females. Weaker males form bachelor groups and hang out, possibly playing Call of Duty and calling each other “bro”.

23.2a – The Slow Loris

Slow and nervous — a toxic combination. (Sunda slow loris photo by David Haring)

In the leafy, tropical forests of southeast Asia, you may happen upon a slow loris — but you would probably never know it.

The slow loris is part of a group known as the lorisids. The ten species of lorisids live in southeast Asia and central Africa, and they include the slender loris, the potto, and the angwantibo. In general they are mid- to small-sized primates with large eyes and very short tails, if they have any tail at all.

But the slow loris is the most interesting of the lot, for one very obvious reason. It is the only type of primate in the world that is venomous.

This trait is extremely rare among mammals. The slow loris does not produce toxins directly in its mouth, but has a rather ingenious system in place. It produces a compound from a gland on its arm, and when it licks this gland, the compound mixes with its saliva to form a toxin inside the mouth. That sounds somewhat foolish and dangerous, but the toxin doesn’t harm the loris — it only harms things the loris bites.

But a slow loris is not an aggressive creature; its bite is used only in self-defense. The animal also licks the toxin into the fur of its young, so that predators will be less likely to look upon a slow loris as a tasty snack.

These precautions are important because of how the slow loris moves — as you might have guessed from the name, it moves very slowly. If you are fortunate enough to spot a slow loris in the jungle, chances are very good that it will be creeping along at a snail’s pace, or not moving at all. It has strong hands that can clamp onto a branch so tightly that it takes a serious effort to make them let go, so they have no problem just hanging around and not moving at all, sloth-like.

But what we didn’t understand about this is that the slow loris is only slow when we’re watching it. This is an interesting effect in science — the notion that a thing might change simply because it is being observed, which in turn means that any conclusions we draw from our observations may be false.

The thing is, the slow loris, and indeed all of the lorisids, move slowly when they feel there might be danger nearby, and in their eyes anything that moves is a potential danger. In their dense, leafy homes, moving slowly helps them blend in and avoid being spotted and eaten.

But put a loris in an environment where it feels safe, such as darkness, and it will move about normally, yet it wasn’t until we had the proper technology that we understood that. So we named it the slow loris, and the name has stuck. However, there is still one difference between a loris’s normal movement and what you would expect from a primate — the slow loris does not jump. At all. It has no future in basketball.

Slow loris species are either vulnerable or endangered, for two reasons. One is a reason that threatens many species in southeast Asia, namely habitat destruction from deforestation to clear land for human use or consumption. The second reason is the wildlife trade. Slow lorises are popular as exotic pets, but this is very bad for the species. In order for a slow loris to become a human pet, its teeth are usually removed so that it cannot inflict its toxic bite (which is painful but not fatal to humans). Many of these animals eventually die from infection or malnutrition after having their teeth removed.

A baby slow loris has its teeth removed with nail clippers before it becomes a pet. Yes, it’s just as bad as it looks. (Photo by International Animal Rescue)

People like slow lorises so much because they are docile, agreeable pets, but you must remember — the slow loris acts slow and docile only when it is feeling threatened. The cuter it looks, the more it fears for its life. Life as a pet is not good for a slow loris, but people all over the world own them. Since 2007 it has been completely illegal in every country in the world to import a slow loris, but exotic pet traders still find ways to smuggle them into other countries and sell them, often to people who don’t know that they are illegal.

To make a long story short, don’t ever buy a slow loris as a pet. Most die in captivity, and live unhappy existences up until they do, but so long as people are willing to pay for them because they are cute, there will be those who circumvent the law to take them from the wild and sell them.

23.1f – The Sportive Lemurs

Loner lemurs. (Sahamalaza sportive lemur photo by R. Hilgartner)

At long last we have scrambled across the entire island nation of Madagascar, we have scoured its corners and learned about the lemurs, that remarkable, cooperative, sometimes strange, often endangered branch of the primate group. Only one family of lemurs remains unaccounted for — the sportive lemurs.

While most of the lemurs we’ve seen so far have been generally kind, sportive lemurs do not like members of their own species and gender. They are nocturnal lemurs, about a foot in length with a tail that goes on for another foot, and they live alone. Males and females have their own territory, and these may overlap, but no male is allowed to overlap his territory with another male, and similarly no female is allowed to overlap her territory with another female. If this happens, whoever was there first will get very angry, rather violent, and there will be a fight.

Like many lemurs, sportive lemurs stick to the trees when they can, but when drawn to the ground they move about in hops, more like a kangaroo than an indriid. Sportive lemurs are on the whole not as active as the other lemurs. They rest and conserve energy during the day, and when they come out at night, though they are very good climbers and jumpers, they keep their activity rate to a reasonable level and don’t make a fuss. A sportive lemur would much rather pass by unnoticed if it can.

Sometimes it’s hard to tell a sportive lemur apart from a woolly lemur, or even a large dwarf lemur. The trick is in the ears. Sportive lemurs tend to have big ears. If you see a lemur with big round ears sticking out from its head, you’ve probably got a sportive lemur situation on your hands. Let the poor fellow pass on into the night in peace.

There is something of a funny trend in recent animal discoveries, and the sportive lemurs give me a chance to touch on it. Once upon a time animals were named almost exclusively for their physical characteristics. If a lemur has white feet, it becomes the white-footed sportive lemur. If it has small teeth, it becomes the small-toothed sportive lemur. That sort of thing. Other times the animal is named for its location in a given area — if it’s found to the north of that type of animal’s range, perhaps it might be named the northern sportive lemur, for example. This is all relatively straightforward.

As you get away from the better-known animals in a group, particularly in a group with a lot of different species, you start to find animals that are named after a person, often the person who discovered it, but sometimes as an homage to someone who did a lot of work with that type of animal. At times this leads to a straightforward name — there is Hubbard’s Sportive Lemur, for example, or Scott’s Sportive Lemur, even Otto’s Sportive Lemur. Other times it leads to names that have a bit more flourish to them — for example, Flaurete’s Sportive Lemur, or Randrianasolo’s Sportive Lemur.

And sometimes, once in a great while, they name a lemur after something that doesn’t even sound like it should belong in the realm of animal names. When a research team discovered a new type of lemur after twelve years of work, they decided to name the lemur after their sponsor, the Association Europeenne pour l’Etude et la Conservation des Lemuriens (The European Association for the Study and Conservation of Lemurs). And thus, AEECL’s sportive lemur was born. You are supposed to pronounce each letter separately, like an acronym. And yes, that is the animal’s official name. I am certain that the AEECL has done fantastic work with lemurs and deserves every accolade they can receive; it’s only that my sense of aesthetics wishes they could have found a better-sounding name for their lemur.

“Wait, my scientific name is Lepilemur aeeclis? You guys have got to be kidding me.” (AEECL’s sportive lemur photo by U. Thalmann)

23.1b – The Dwarf Lemurs

The littlest lemurs. (Gerp’s mouse lemur photo by Blanchard Randrianambinina)

Though all of the lemurs found on Madagascar are a little on the small side — there is, after all, no evolutionary pressure to grow large when you have no competition and live on an island with limited resources — the dwarf lemur family contains the smallest members, and in fact they are the very smallest primates in the world.

There are 31 different species of dwarf lemurs, though many of them are known rather as mouse lemurs. Even the largest is less than a foot tall, and they have exceptionally soft hair. All of the various dwarf lemurs spend nearly their entire lives in trees, where they are agile and comfortable; on the ground they hop on their hind legs like tiny kangaroos, and become easier targets for predators.

As a nocturnal species, dwarf lemurs are not generally as social as most other primates. They tend to live alone or in pairs, though some of them form big sleeping groups during the day so they can snuggle up together. Some of them store fat in their tails, so if you see a dwarf lemur with a big chubby tail, you know it’s well-fed. During dry times and times of food shortages, many of the dwarf lemurs enter a torpor, in which they sit around and use very little external or internal energy to help them survive until food returns.

One of them, the fat-tailed dwarf lemur, enters a full hibernation during the dry season. It is the only tropical mammal and the only primate known to hibernate (discounting, of course, human teenagers during Christmas break). This is interesting because most animals hibernate because of the cold; but even during the dry winter, Madagascar is still very warm, and the fat-tailed dwarf lemur’s body temperature tends to go up and down depending on the weather outside, even while it’s hibernating.

“If your tail was this fat, you’d be sleepy too.” (Fat-tailed dwarf lemur photo by Petra Lahann)

The mouse lemurs are even smaller than the other types of dwarf lemurs. For a long time we didn’t know a lot about mouse lemurs for the simple reason that we didn’t know how many there were. All of the various mouse lemurs look similar to each other, so for a long time we thought there was only one kind. But in the last 35 years we have determined that even though they look alike, there are actually 19 different species of mouse lemur scattered around Madagascar, and perhaps more that we haven’t found yet. One of them, Gerp’s mouse lemur, was only discovered this very year, in 2012.

The smallest primate in the entire world is Madame Berthe’s mouse lemur. It averages only about three and a half inches long, and weighs only an ounce. It can be found only in one small national park on the western coast of Madagascar, and its interesting name comes from Madame Berthe Rakotosamimanana, a woman from Madagascar who founded the Group d’Etudes et de Recherche des Primates (Group for the Study and Research of Primates). Be thankful they didn’t use her full name for the species.

There are no freely-available photos of this lovely small primate, but if you are so inclined, you should click through to this photo to see a baby Madame Berthe’s mouse lemur, which I think you’ll agree is about the most adorable it is possible for a primate to be.

One of the most interesting things about the mouse lemurs is that they all somehow agree to get along and not bother one another. An extensive study was done on Madame Berthe’s mouse lemur and the gray mouse lemur, which live close to one another. They eat the same things and live in the same type of habitat. The gray mouse lemur is larger, stronger, more adaptable, and better able to survive; if it wanted, it could easily push the smaller mouse lemur out, perhaps to extinction. But it does not. The gray mouse lemur’s territory goes right up to the edge of the territory used by Madame Berthe’s mouse lemur, and there it stops.

Why? We don’t know. There are very few animals in the world that share the same resources and the same habitats without one suffering from the presence of the other. But the mouse lemurs, for whatever reason, are content to live with what they have, in the area they call their own, and not to bother their neighbours. If only some of the larger primates could be so reasonable.

“Hi there, neighbour.” (Brown mouse lemur photo by Frank Vassen)

In fact, some dwarf lemurs and mouse lemurs have territories so small that they can only be found around the region of a single village. They are blips on the map, but they are there, living their tiny lemur lives.

But like many lemurs, they are threatened by deforestation across the island. It is entirely possible, given the miniscule territories of some recently discovered mouse lemurs, that entire species of these diminutive primates have already been destroyed before they were ever discovered.

Dwarf Lemur distribution