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

7.3c – The Tasmanian Devil

The devil is in the details. (Photo by Noodlesnacks)

If you are like me and grew up with Looney Tunes cartoons, the name Tasmanian Devil brings to mind a whirling, angry, garble-talking beast. This depiction is not quite accurate, but the actual animal, an endangered carnivorous marsupial found on the island of Tasmania, is still every bit as remarkable. Yet sadly, this unique creature is now dying out because of a terrible disease.

The Tasmanian devil is the size of a small dog, but it is the world’s largest carnivorous marsupial now that the thylacine is (probably) extinct. It is fast and strong, it can climb trees and swim rivers, it both hunts and scavenges, it has a tremendously powerful bite, it has a sense of smell like nobody’s business, it in turn smells awful, and it is a loud, angry-sounding creature. So a bit like a deranged, drunk hobo with a knife.

They once lived throughout Australia, but were all killed on the mainland sometime in the past 3000 years, possibly by dingoes, which are feral dogs first brought to Australia by humans.

The childhood of a Tasmanian devil is not an easy one. A female gives birth to a remarkable 20 to 30 young at a time, but she has only four nipples in her pouch, meaning that most of the young will soon die and only the strongest or fastest will live. This is an evolutionary failsafe of sorts, ensuring that the devils stay strong and fast as a species, which they need to compete for food and stay alive.

Once it grows up, however, a Tasmanian devil is a tiny force to be reckoned with. It has a scent gland much like a skunk, which it uses to mark the ground with a powerful, awful odor. Its jaws are so strong that they can crush bones and bite through metal wire. In fact, so much of the animal’s strength is concentrated in its jaws that it has a disproportionately large head, which gives the animal a strange, shambling sort of movement when walking.

Most devils hunt during the night, using their black fur, their sensitive whiskers, their great eyesight, and their ability to smell prey more than half a mile away to their advantage. Some however can hunt during the day, and the Tasmanian devil is one of the few marsupials capable of being active in the Australian midday heat.

Like the quolls, Tasmanian devils are solitary creatures but sometimes feed together and often have communal pooping spots. Unlike many solitary animals, they are not territorial. There can be a large concentration of devils in a small area without any problem; they simply won’t interact any more than they have to, though males will fight during mating season.

When hunting they can be fearsome, taking down small kangaroos or sheep, sometimes fish or fruit or frogs or insects, but most often wombats, and even more often it will simply find some carrion to scavenge and not waste time on hunting. No fool, the Tasmanian devil. When they live near humans, they like to steal shoes and chew on them, and have also been found to eat pencils, plastic, and denim jeans. All right, maybe a little foolish.

"Be honest. Do these pants I ate make my butt look fat?" (Photo by Mike Lehmann)

When a devil finds a meal, it wastes neither time nor opportunity. It will dig in with fervor and gusto, and can eat up to 40 percent of its body weight in one sitting, becoming so fat and bloated that it can only waddle away and find somewhere to lie down. When there are several devils in an area, they can pick a carcass clean before it rots.

In fact, devils seem to like to eat together, even though they normally ignore each other and never so much as wave hello when they pass on the street. But when a devil makes a kill or finds a good meal, it doesn’t mind at all if other devils come and join it. It is perhaps the only carnivore that lives alone but eats in groups. Up to 12 animals will eat at the same kill, and they make loud growling and ripping and eating sounds together, which is what inspired the sounds made by the cartoon character. It is believed that the loud eating noises are a way to advertise to other devils in the area that there is good eating to be had. Tasmanian devils are not greedy.

They are, however, sort of mean. Even though the devils advertise their food, they will squabble with each other when it comes to eating. Older devils will chase younger ones away, and the animals that never talk to each other elsewise are shown to have developed at least 20 different communication postures used while feeding together. They sometimes sumo-wrestle by pushing each other with their paws, and they will bite one another seemingly at random while eating, which is why many devils have scars around their face or rump. They don’t seem to mind. It’s all part of the Tasmanian devil lifestyle.

The devils are endangered for a number of reasons. They were once widely hunted, trapped, and poisoned by farmers, but the population became protected after the extinction of the thylacine, and slowly recovered. Surviving the wrath of humanity, they now sadly suffer from devil facial tumour disease, which is a terrifying affliction.

First appearing in 1996, it is essentially a contagious cancer that has spread across most of Tasmania and only affects Tasmanian devils. Though the original source of the cancer is unknown, it may have started due to human chemicals in the environment that concentrated in the devils, at the top of the food chain. How does it spread? Unfortunately, it mostly spreads when the devils randomly bite each other during feeding, and it is thought that as many as 80 percent of wild devils are currently infected. Sick devils are removed from the population to prevent further spread of the cancer, but there is no known cure. It is killing the devils faster than they are able to reproduce.

It is one of only three known contagious cancers in the world. This extremely rare form of cancer is possible because the cancer cells themselves are transmitted to new hosts, like a virus, and then clone themselves within the new body even though that body’s own cells are healthy. If that sounds terrifying, well, that’s because it is. The other two contagious cancers are the canine transmissible venereal tumour (passed between dogs through sex) and a reticulum cell sarcoma found in the Syrian hamster.

Scientists have gathered healthy devils to keep in captivity as a means of preserving the species in case the wild devils all die from the disease, which unfortunately is likely to be the case if new treatments aren’t found. Scientists are continuing to search for ways to stop the disease. It is estimated that at the current rate, Tasmanian devils would become extinct by 2035, but breeding healthy devils in captivity and quarantine may help the species live on. There are somewhere between 10,000 and 15,000 Tasmanian devils left in the wild.

7.3a – The Quoll

Potty pals. (Photo by Michael Barritt & Karen May)

The quoll is a carnivorous marsupial that looks something like a cross between a cat and a rodent, a hybrid appearance that would surely horrify either group. There are six species of quoll, once found throughout Australia, Tasmania, and New Guinea, but now found only in smaller areas in those three locations.

The biggest quolls are between two and three feet long, while the smallest are only about a foot long. They hunt along the ground or sometimes in trees, eating insects, birds, frogs, rabbits, possums, or other small creatures.

They are mostly nocturnal, solitary creatures, living and hunting alone, with one notable exception — quolls like to go to the bathroom together.

It’s exactly as weird as it sounds. Male and female quolls have overlapping territories, but they only interact with each other during mating season or at their joint latrine, an agreed-upon spot within their territory where they will go when they need to defecate. They just pop all their pellets down into the same spot, over and over again, and will visit if they happen to be doing their business at the same time. Maybe one of them brings a newspaper, I don’t know.

Most quolls are also strange because, with the exception of the large tiger quoll, they only develop a pouch when they get pregnant, and otherwise have only wrinkly skin around their bellies. The pouch, when it develops, faces backward instead of forward, and if the mother stands up on its hind legs the babies have to hold on or risk slipping out.

"Wheeee!" (Photo by Figaro)

Speaking of babies, a mother quoll will typically have an impressive 18 at once, but only six of them will survive the journey to the pouch and the race to reach one of her six nipples. The victors will latch on and not let go, leaving the other 12 brothers and sisters to die of starvation. When it comes to survival in the wild, most animals are highly pragmatic. If the six that win the race are the strongest, then that’s what is best for the species in the long run. You can’t apply that logic to humans however, as human society is so complex that raw physical strength and speed are not the only things we need.

There are many fewer quolls than there used to be, and living in vastly reduced areas, but only one of the six species, the northern quoll, is considered endangered; the others are near-threatened. Quolls face competition for food from invasive foxes and cats, and also face two other major threats.

The first is one of those regrettable and illustrative stories about invasive species in Australia. There is a natural insect in Australia known as the cane beetle. When humans introduced sugar cane crops to the country, the cane beetles loved them, and damaged the crops. To solve this threat against their non-native crop, Australians in 1935 introduced cane toads from South America to the country, so that they would eat the beetles.

Only a few hundred toads were released, just to be on the safe side, but their population grew exponentially and there are now more than 200 million invasive cane toads in Australia. Why is that a problem, you ask? because the cane toad, as it happens, is highly poisonous.

Quolls enjoy snacking on a good frog whenever they can find one, but eating cane toads kills them. A large number of quolls have fallen prey to this trick of fate, to the point where some people are trying to teach quolls how to recognize and avoid the deadly toads. Cane toads can also spit venom, meaning that even a quoll that gets too close can be hurt or blinded. South American animals, having evolved alongside the cane toad, know how to deal with all it, but Australian animals do not.

In addition, humans commonly use poisoned meat in an effort to get rid of the enormous numbers of invasive cats and foxes. Unfortunately quolls also like free meat, and many have been poisoned. It is unknown if the quolls benefit more from the removal of predators than they would benefit if they weren’t being tempted with toxic snacks, but either way it is a purely unfortunate situation.

7 – The Book of Dasyuromorphia

Hungry marsupials with a hankering for meat. This is a quoll. (Photo by Leonard G)

Dasyuromorphia (pronounced da-see-YUR-oh-MOR-fee-uh) is quite a name, and with seven syllables you know it’s serious, but you won’t be required to remember it for the test. There’s an easier way to remember what they are, because if you had only two words to describe them, those two words are readily available — carnivorous marsupials.

We haven’t looked at marsupials yet, so it’s worth a moment to pause and do so. Marsupials are an older, more primitive form of mammal that give birth to under-developed young. After the young are born, they move into a pouch on the mother’s body, where they can feed and grow larger before venturing out into the world. All baby marsupials are known as joeys, even though the term is commonly used for baby kangaroos. Kangaroos are marsupials, as are koalas, but there are many more than that. There are in fact more than 300 species of marsupials, found in Australia, New Guinea, South America, and a very few in central and North America. Marsupials have developed a lot of different forms, some of which resemble non-marsupial forms because of convergent evolution.

Dasyuromorphia is an order with about 70 species, all of which are meat-eating marsupials found in Australia. There are some carnivorous marsupials found in the Americas, but they were turned away at the door of the Dasyuromorphia Club. Included in this order are a lot of mammals with fantastic names that you’ve probably never heard of, such as quolls, dunnarts, planigales, and the numbat, along with some you have heard of, such as the Tasmanian devil and the extinct thylacine (the Tasmanian tiger). We will soon make certain you have heard of them all! Some of them look sort of like cats, and some look sort of like shrews or mice, but they all have a unique marsupial twist, and they (almost) all have the marsupial pouch with which to carry their joeys.

A few of these animals have some good size to them, but most of them are very small, and because of this many of them are threatened by the plague of invasive species that has swept over Australia in the last century and more, including foxes and cats. You might wonder, how are they carnivores if they are so small? After all, the smallest member of this order is only half the size of a mouse. Shouldn’t a carnivore be big enough to attack things? Well, the trick is that to be a carnivore, you only have to be bigger than something else you can eat. Small carnivores merely need to attack small prey.

It is also worth noting that there used to be several larger marsupial carnivores in Australia, but humans caused all of them to go extinct since our arrival on the island continent 50,000 years ago. The most recent casualty of our presence was the unique and strange thylacine, which was lost entirely by the 1930s. We will still take a look at it, along with all of the other interesting animals in this order.

Dasyuromorphia distribution.