23.4a – The New World Monkeys

Out with the old, in with the new. (Common squirrel monkey photo by Geoff Gallice)

A whole new world! A dazzling place you’ve never been! Or so goes the song, but if you’ve ever been to the Americas, North or South, you actually have been there.

Here at last we come to the sorts of animals we imagine when we think of primates — the monkeys. And let me tell you, there are a lot of different monkeys out there. Most of the warm places in the world are crammed full of them. But one type of monkey is not quite like another. Scientists who work on these sorts of things have divided monkeys into two major groups — the old world monkeys, those that evolved in Africa and Asia; and the new world monkeys, those that evolved in central and South America.

The two groups split apart about 40 million years ago, but the curious thing is how that came to happen. After all, 40 million years ago there was no known connection between South America and Africa or Asia. We know that monkeys originally developed in the old world, so how did they come to be in the new?

The obvious thought is that they crossed the land bridge that once existed between Russia and Alaska, the same way humans eventually did, but we don’t think that’s what happened. There is absolutely zero fossil evidence to suggest that monkeys ever moved through North America or Siberia. And besides, North and South America were not yet connected, and wouldn’t be for tens of millions of years, so if monkeys had come through North America they would have been forced to stay there for a long time. As far as we know, that’s not what happened.

But there’s another way they could have made the journey. We have no way to know for certain, but the idea is that those ancient monkey pioneers that made the trip to South America to become a new type of monkey actually came from Africa, and crossed the Atlantic Ocean.

Now the Atlantic Ocean is very big, so I understand if you’re skeptical. It’s not as though the monkeys of 40 million years ago could build boats. But remember that South America and Africa are moving apart from one another, which means that the Atlantic was quite a bit smaller back then. It was still, however, a very formidable stretch of ocean, on the order of a thousand miles wide, if not wider.

The current theory goes that there existed at that time a number of islands between Africa and South America, stretching across that growing ocean. This is certainly possible, and the ocean levels of the world were a bit lower back then as well, so there may have been islands. The monkeys may have more or less accidentally crossed them over the course of many thousands of years, populations swept westward on floating debris and material with the currents (which were also different then than they are today).

So it came to be that monkeys, those adaptable, adorable, terrible creatures, set foot on a brave new world and took to the great jungles of South and central America. But what makes a new world monkey special, besides its geographic location?

Is it the fabulous whiskers? (Emperor tamarin photo by Brocken Inaglory)

New world monkeys are typically a little smaller than their old world counterparts, but the nose is where it’s at. Just as we split wet-nosed primates apart form dry-nosed primates, monkeys too are divided by what’s around their nostrils. New world monkeys have flatter, more narrow noses than the old world variety, and their nostrils face to the side instead of down or straight ahead. The new world monkeys also have prehensile, grasping tails, while the old world monkeys are stuck with tails that can’t grasp a thing. To balance this out, most new world monkeys do not have opposable thumbs, either, while the old world monkeys — and by common evolutionary ancestry, us — all have that useful trait.

There are five families in the new world monkey group, and we will examine each of them in their turn. Among them we will find monkeys that swing, monkeys that howl, and the smallest monkey in the world. The new world monkeys are unconscionably addicted to trees, and they show it in some of their names. We’ll have squirrel monkeys, owl monkeys, spider monkeys, and more. But enough with the introduction. It’s time to monkey around.

23.1a – The Lemur

Wet-nosed in a world of their own. (Mongoose lemur photo by IParjan)

For much of its history the island of Madagascar has been shrouded in mystery. Separated from Africa 160 million years ago and from the northward-bound India 90 million years ago, it has been one of the largest isolated areas for evolution outside of Australia, and like that continent-sized country Madagascar is home to many types of creatures found nowhere else on Earth. We looked earlier at the fossa, the Malagasy carnivore that evolved to look like a cat, but the most distinctive animal found on the island is the lemur.

Lemurs branched off from the rest of the primates sometime shortly after the dinosaurs went extinct. In the period from about 65 millions years ago to 50 million years ago — we aren’t exactly sure when in that time frame — the ancestors of all modern lemurs crossed the 350 mile channel between Africa and Madagascar and started an entire new branch of the primate family tree.

How did they cross the channel, you ask? For a long time this was one of the many mysteries of science, because that’s a lot of ocean to cross and the currents go the wrong direction. But it’s recently been proven that because both Africa and Madagascar were further south when the migration happened, the currents back then were in fact going the other way. Thus it is very likely that the ancestral lemurs lived along the African coast and crossed on rafts of vegetation by accident in multiple incidents over millions of years, swept across the channel by the current. It would have been a 30 day crossing for the creatures, difficult but survivable.

When they arrived, singly and in bunches over millions of years, they found what would prove for a long time to be a primate paradise — an uninhabited, unspoiled, enormous rainforest island, a place of wet seasons and dry seasons, a place with few competitors and few predators. And the lemurs took full advantage.

In their tens of millions of years on the island, lemurs evolved into many different forms to take advantage of all the resources and habitats on the island. Some became very small, as small as 30 grams, while others became very large. The largest lemur ever known was Archaeoindris, a lemur that evolved into a shape and size similar to a gorilla, weighing up to 400 lbs. They evolved into all sorts of behaviors, eating habits, movement types, social groupings — the lemurs formed their own diverse range of species on the isolated island, because they had no competition and were not forced to focus on only a few types of living.

But lemurs did not evolve quite the same as the more modern simians such as the monkeys did. Lemurs share the common primate features discussed in the previous article, but they have smaller brains relative to their body sizes, making them generally less intelligent. Lemurs can be taught to use tools in captivity, but they do not do so in the wild.

Either that, or they’re trolling us. Hey, lemur on the right, I see you laughing back there! (Ring-tailed lemur photo by Chris Gin)

Lemurs also have hands that are poorer at grasping than the hands of more modern primates, and lemur tails are not prehensile. This means that lemurs are not so acrobatic in the trees, but they can still get around just fine, and some are almost as good at it as monkeys. In addition, lemurs have generally poor eyesight.

To make up for these downsides, lemurs evolved powerful noses for more than just sniffing. Their noses are constantly wet and can be used as a touch-based sensory organ that lets them smell scent markings left by other lemurs by touching their nose to the marking. Through this method lemurs communicate information about themselves — their territory, their individuality, their gender, etc — without having to see one another, which comes in handy in the dark. Most lemurs are nocturnal, but some come out in the morning and evening as well.

One other thing that all lemurs have in common is the toilet claw. Besides being an object with a great name, the toilet claw is a longer nail on the second finger that is used for scratching and grooming.

But back to Madagascar, where all the lemurs were forming their lemur kingdom in isolation, with no worries and no competition, free to evolve however they wanted to take advantage of the island’s many resources. They were the ghosts of the forest, emerging in the evening and throughout the night to run wild through the rainforests, and indeed that is how they got their name — the word “lemur” comes from a Roman mythological term for ghosts.

“… Boo.” (Red-bellied lemur photo by Rachel Kramer)

But about 1800 years ago, everything changed. That’s when humans not from Africa but from Borneo in Indonesia discovered the island and native tribes colonized it. They were later followed by people from Africa. Together they are today known as the Malagasy people, and with their coming everything changed for the lemurs.

The Malagasy burned and cleared large sections of the rainforest to make room for pastures and rice paddies. So thoroughly did the Malagasy colonize the island that the lemurs, once found everywhere, were soon relegated to only about ten percent of the island’s area. The larger lemurs, including the enormous Archaeoindris, were killed off — as far as we know 17 different species of lemur went extinct in the 1800 years after human arrival.

And that was without hunting. Though the early human activity greatly damaged the lemurs, the people did not hunt or eat them. Lemurs are the subject of a great number of taboos from the native people, and it is believed to be extremely bad luck to harm a lemur.

European scientists have known about lemurs since the 1700s, but almost everything we know about them comes from research that took place only in the past 30 years. We used to believe there were only 30 or so lemur species, but today we know there are nearly 100 different species. Some of the species look so similar that we can only tell them apart with genetic testing.

These hundred or so species of lemur are split up into five major categories, or families, though as always science has not settled on the exact truth of this classification arrangement. Most species today are endangered or threatened due to human activity, especially logging of the Madagascar rainforest.

In the following series of articles we will look at each of the five major lemur families and learn more about these diminutive, diminished former rulers of the isle of Madagascar.

Lemur distribution

20.3a – The Tapir

The beast with the shotgun nose. (Photo by Sepht)

Imagine a thick and humid forest in South America, where vegetation grows thick and small things live in profusion. Even the dogs that migrated to this continent grew small so that they could easily move around. But suddenly, snuffling through the jungle comes something bigger, something much bigger. Six hundred pounds of something like a cross between a pig and a small elephant rushes through the trees with a crash, and you wonder why on earth you’ve never heard of this before.

The tapir (pronounced TAY-per) is one of the largest land animals in the world that the average North American has probably never heard of. If asked to list large land animals, people would name the elephant, the rhino, the hippo, the bear, the giraffe, the lion, the tiger, but who would remember the tapir? There are four species of tapir, two in South America and two in southeast Asia. They are part of the same order as rhinos and horses, but they look nothing so much like the largest, strangest pig you’ve ever seen.

A tapir is about seven feet long and three feet tall with splayed, padded feet, each toe having its own hoof, capable of walking on mud without sinking. But the strangest thing you’d notice about a tapir — the strangest thing you’ve already noticed about it from the picture above — is its snout.

The snout on a tapir is long and flexible. It’s nothing compared to an elephant’s, but it’s the start of a similar idea. The tapir can move its snout in all directions and use it to reach branches and plants that would otherwise be just slightly out of reach.

And it makes them look just a little like Alf, the ’80s sitcom space alien. That’s not just me, right? (Mountain tapir photo by Elissa Berver)

A tapir’s teeth are also worth mentioning. The cutting teeth are set way out at the front of the long head, while the chewing teeth are much further back, and the two sets are separated by a gap. When combined with the fact that the entire snout is boneless, this gives the tapir a uniquely strange-looking skull.

Tapirs can smell and hear very well, but they have poor eyesight. They can run quickly and like to move around in the water much like a hippo. They have thick skin and only the biggest, strongest predators pose much of a threat to them.

Unfortunately that’s once again where we come in. Due to hunting and habitat loss, all four species of tapir are considered either endangered or threatened.

You might wonder how such a big animal came to live in both South America and southeast Asia, which are after all very far apart. Originally tapirs lived across almost the entire northern hemisphere, including North America, Asia, and Europe. But the northern tapirs in the old world all died out by about 8000 BC, leaving only those in southeast Asia; and in the new world, the tapirs of North America migrated south when the two American continents joined together three million years ago.

Tapirs are nocturnal creatures for the most part, but you must be careful if you ever meet one in the jungle at night. A tapir will typically avoid people by running or jumping in nearby water, but when frightened they have on rare occasions been known to maul humans with their jaws. And telling your buddies that you lost your arm in the Great Tapir War is not as credible as it sounds.

Tapir distribution.