23.1e – The Indriids

The lemurs of hip-hop. (Diademed Sifaka photo by Tom Junek)

In the mad, mad world of lemurs in Madagascar, we’ve looked at the tiny dwarf lemurs, the bizarre aye-aye, and the typical lemurids, but those aren’t all. There are even more types of lemurs sharing the treetops on this crowded island.

There are 19 different species of indriids, and we can roughly divide them into three types — the woolly lemur, the sifaka, and the indri. The basic thing that sets indriids apart from the other lemurs is that they are not very good at moving on the ground. An indriids hind legs are very much longer than their arms, and this means that they cannot move around on all fours, as the lemurids do.

To visualize their dilemma, try it yourself, for humans suffer the same problem. Try to move not on your hands and knees, but on your hands and feet. You will quickly see why indriids don’t really like to move around this way. But unfortunately for the indriids, they aren’t able to walk upright in the manner of humans either. What’s a poor indriid to do?

Well, for the most part they stick to the trees, where they are incredibly agile and can jump great distances with their long, powerful legs. But they don’t hesitate to use the ground when they have to. What they do is stand up tall on their hind legs, stick their arms in the air for balance, and hop.

The sifakas are the best at this, or at least the most interesting to watch. They take great, sideways leaps across the ground in order to cover distance as quickly as possible. I cannot embed videos on this blog, but if you would like to click on the following link it will open a new window in which you can see the sifaka doing its wonderful thing.

https://www.youtube.com/watch?v=f9ARvGS3mhk

The woolly lemurs are much like the sifakas, but the indri is the odd animal in the group — every family has at least one. The indri is one of the largest of all lemurs, measuring up to two and a half feet, not including its tail. The reason it’s not fair to include the tail is that the indri, well, does not really have one.

Every other type of lemur on the entire island has a magnificent tail, sometimes longer than the entire rest of its body. These tails are used for balance and sometimes for stink-fights, as we saw with the lemurids. But the indri has only a tiny knob of a tail, hardly even worthy of the name. Despite this balance handicap it still climbs and jumps around in the trees as well as anything, and still does the side-stepping hop-along movement on the ground.

No tail? No problem. (Indri photo by Erik Patel)

One interesting thing about the indri is that it is entirely monogamous. It is one of those rare species that mates for life; a mating pair will stay together and raise multiple generations of offspring — one at a time — until one of them dies, and will only then move on to seek a new partner.

Indris are very vocal, and different groups will “sing” to one another. Their songs can last several minutes at a time, and when one group is finished singing another group nearby may take up the tune. We aren’t entirely certain why they do it, but it may simply be a means of letting all the other indris know where they are. There doesn’t seem to be any one reason why they do it, however. Indris will sing after some loud noise has disturbed them, will sing to respond to other groups singing or even to other types of lemurs making noise, and sometimes will sing seemingly just because they want to. A group of indris might sing up to seven times a day, and their songs resemble in some ways those of humpback whales.

To hear what an indri’s song sounds like, give this link a gander: https://www.youtube.com/watch?v=4d3vFI5UpIc

In some ways the indri is one of the most advanced lemurs, and the natives of Madagascar treat it as a sacred animal. In local mythology, the indris and humans have close relationships. One myth tells the story of two brothers, long ago. One brother decided to leave the forest and cultivate the land, and he became the first human; the other brother stayed in the forest and the trees, and became the first indri. The myth says that the indris sing as a form of mourning for their long-lost brothers who left the forest.

And if that isn’t wonderful enough, the Malagasy people also believe that the indris worship the sun, much as a human would worship a god. There is a surprising amount of truth to this idea. Every morning when the sun rises, an indri will face it and sit cross-legged, back straight, palms in its lap or facing up, and watch the sun with eyes half-closed, the very image of a human in meditation. It is not believed by scientists that indris have enough social organization to actually be worshiping the sun, of course; it is most likely only a coincidental body posture and a desire to warm up in the morning. But it is wonderful all the same, and these strange, knob-tailed lemurs have a lot of surprisingly human-like features for being so far removed from us in the primate group.

Unfortunately, the indri is also endangered, highly threatened by habitat destruction. They do not survive in captivity, and have never been successfully bred, which means that without adequate protection this wonderful creature, and indeed many of the indriids, may someday soon leave our world forever. It is unfortunate that Madagascar combines at the same time such a rich diversity of species and such a lack of environmental protection, due to the material needs of a poverty-stricken society.

13.1a – The Leporids

If I told you this black-tailed jackrabbit wasn’t really a rabbit at all, would you accuse me of splitting hares? (Photo by Jim Harper)

There are about 60 types of leporids, which are about evenly divided between the rabbits on one hand and the hares on another.

Most people don’t know the difference between a rabbit and a hare, but there are a few things that set them apart from one another. Visually, the biggest difference is that hares are usually larger than rabbits, have longer ears, have longer hind legs, and often have black markings on their fur.

But that’s not the only way to tell them apart. Most rabbits live in underground burrows, often in family groups, whereas hares live above ground in nests, and are usually found alone. The exception to this rule is the cottontail rabbit, which is an oddball rabbit that lives in nests above the ground like a hare. The other rabbits don’t like to talk about the cottontail.

Another difference is that rabbit babies — known as kits — are born blind and hairless. Hare kits are born with hair and have perfectly functional eyes. This is related to how they live. An animal — especially a prey animal — that is born above ground must be able to see very soon after birth if it is to survive; an animal born beneath the surface has the luxury of time to develop.

And finally, rabbits have been domesticated by humans in a variety of forms, while hares are much more wild and have never been domesticated.

Confusingly, you can’t always tell a hare from a rabbit just by reading its name. Usually this is a safe way to steer, but there’s a common animal known as the jackrabbit that is not actually a rabbit at all, and is rather a hare. In addition, the hispid hare in Asia and three species of red rock hare in Africa are actually rabbits. Way to go, naming conventions. You really came through on that one.

In any case, once you get past the differences, rabbits and hares are fairly similar. They are both hippity-hopping little creatures that eat plant matter, scamper at the first sign of danger, can live just about anywhere, and have big ears.

“They’re not big, they just … they stick out a little, that’s all.” (Photo by Jessie Eastland)

A leporid’s long ears give it a fantastic sense of hearing, and they can rotate their ears like radar dishes to face any direction. It is very hard to sneak up on a leporid.

They also have distinctly good night vision, but contrary to popular myth, this isn’t because they eat a lot of carrots. Rabbits and hares in the wild don’t actually get carrots very often, as even when they raid a garden they will only eat the green tops off. Carrots have Vitamin A, which is good for maintaining eyesight, but it won’t make your vision any better than it already is.

In fact, the myth of carrots giving you better eyesight was fabricated during World War II in Britain. The British had developed a radar system to help them track German fighters coming over the English Channel in time to scramble defenses, but naturally they didn’t want the Germans to know about it. So instead they came up with a lovely story about how British pilots ate lots of carrots, which gave them great vision, which allowed them to find and shoot down lots of German planes. It was a complete lie, but lots of people believed it, and still believe it now.

An interesting fact about rabbits and hares, and one that isn’t generally advertised, is that they are coprophages. That’s a fancy word that means they eat excrement. In particular, they eat their own. They have a perfectly good reason for this — their digestive system doesn’t process all of the nutrients in a food the first time through, leaving a soft and mushy waste matter, so the practical leporid eats it all down again. The second time through gets all the nutrients out, and produces the hard little pellets we associate with them. At this point, thankfully, the leporids stop eating their own poo.

Just as thankfully, they don’t ever feel like sharing it. (Photo by Andrew Easton)

Both rabbits and hares are prodigious breeders, particularly rabbits since their babies are born less developed, meaning they can mate more often. This rabbit-related popular belief is all too true — rabbits really know how to make babies, and how to make them as quickly as possible. A single pair of breeding rabbits can have several litters in a year.

This is bad news for anyplace that doesn’t want rabbits, because the rabbits, once introduced, don’t care what we want. Australia, that whipping boy of the invasive species world, has learned this the hard way.

Rabbits were introduced to the country in 1788, but they were kept in controlled, domesticated forms until 1859, when Thomas Austin released 12 wild rabbits onto his property so that he could hunt them. “The introduction of a few rabbits could do little harm,” he said at the time. Seldom in history has one country so regretted the well-intentioned actions of one man.

The rabbits spread quickly across the continent and have had devastating effects on the native ecology. They have completely destroyed a number of Australian plants, both little plants and big plants like trees, which the rabbits can kill by eating the bark. The loss of so many plants has made this dry country even drier by causing serious loss of soil through erosion.

Australia has tried to stop them. They’ve tried shooting them, poisoning them, destroying their burrows, and even building a rabbit-proof fence across an entire section of the country in 1907. It didn’t really work.

Australians have even tried releasing rabbit-killing diseases into the countryside. In 1950 the Myxoma virus was released into the rabbit population. It is a virus that only kills rabbits, so it was safe to use. The results were astonishing, as all across the continent an estimated 500 million rabbits dropped dead and littered the land. Unfortunately, the remaining 100 million developed resistance to the disease, which they passed on to their babies, and the population rebounded completely. Now there are between 200 million and 300 million rabbits with more every day, and they are all impervious to the Myxoma virus.

This is only part of the bad news story for Australia when it comes to invasive species, and not even the biggest part, but it remains to be seen how or if the country can deal with its enormous leporid population.

5.2e – The Vampire Bat

He doesn't vant to suck your blood. He just vants to lick it a little. (Photo by Ltshears)

There are exactly three bats in the world that feed on blood, and they are the three species of vampire bat, found in central and South America. Lots of bats get a bad reputation because of the vampire bats, but only these three are parasites who live off the blood of living creatures.

Contrary to popular terminology, vampire bats do not “suck” blood out of anything. They use small, razor-sharp teeth to make tiny cuts in an animal’s skin, and then lick the blood that comes out.

One of the most interesting things about vampire bats is how they find sleeping animals and then choose where to make their incisions. Vampire bats have a specially developed sense of hearing that allows them to tell when an animal is breathing the deep, regular breaths of sleep and when the animal is awake. This is important, because sleeping animals are much less likely to notice the small, quick cut or the bat’s licking tongue. Once the bat has a likely target chosen, it uses wonderful thermoreceptors on its nose to find the warmest parts of the animal’s skin, which is where the blood flows closest to the surface. The vampire bats are the only mammals capable of naturally detecting infrared signals like this.

Vampire bats practice something known as social thermoregulation, which is a fancy term that means keeping warm by using friends. Vampire bat colonies can number in the thousands of bats, but within each colony there are smaller groups that roost together. When temperatures are warm, each of these groups will be smaller, and will tend to exclude males. When it gets colder, the groups get bigger, letting more males in as they roost together to keep warm.

But what you probably don’t know about vampire bats is just how helpful and kind they can be with each other. Yes, they are parasites of a sort, and yes, they live off blood instead of fruit or insects, and yes, they are kind of creepy, but they really aren’t so bad when you get to know them.

"I pay my taxes and mow my lawn like anyone else. What I do with your blood in the privacy of your own home is none of your business." (Photo by Acatenazzi)

For example, if a mother bat dies, another vampire bat will adopt any orphaned babies, looking after them, feeding them, and raising them as if they were her own. They are the only bats known to do this. In addition, vampire bats will share food. A vampire bat must feed on blood at least every two days or it is in danger of starving to death. If a bat can’t find food, it will beg for help from the other bats. Some of the other bats will helpfully regurgitate a little bit of their day’s blood food, so that the hungry bat can eat. They will also groom one another socially, much like primates.

Two of the three vampire bat species feed on the blood of birds, and only the third, the common vampire bat, will feed on mammals. They will feed on pretty much any sort of mammal, including humans, which is why we don’t like them. When spotting a target, the bat will land a short distance away and approach along the ground in a stealthy manner. Vampire bats are quite good at moving along the ground, and can “run” at speeds of up to 5 miles per hour, which is a fantastic image.

If the animal has hair, the vampire bat will actually use its sharp teeth to shave away a little patch to reveal the skin, which is quite clever. The bat’s saliva acts as an anticoagulant, which means that it stops the blood from clotting up and scabbing, so that the bat can feed longer from a single cut.

You aren’t in danger of having your blood drained by a vampire bat, as they only take about one fluid ounce of it before they are full and head off to digest your lovely blood. However there is always the chance they might give you rabies. About 0.5 percent of vampire bats carry rabies.

Humans, as we so often do, have fictionalized a lot of the attributes of vampire bats into the mythological idea of vampires. But real vampire bats are not evil. Blood is simply how they survive, and they do not take enough to do real harm so long as they don’t pass on rabies. All the same, it is understandable that we don’t like them. Anything that might feed on us while we sleep tends not to get a page in our good books. But beyond the whole blood thing, they are clever, social little creatures, and utterly unique.

4.2d – The Monodontids

And you thought wisdom teeth were impractical. (Photo by Glenn Williams)

Monodontid is a name that literally means “one tooth”, but the two strange northern whales in this group actually have many teeth. The two whales are the beluga and the narwhal, and the group’s name of course comes from the narwhal’s long, unicorn-like tusk.

Make no mistake, it is a tusk and not a horn. The narwhal grows an incisor tooth on the left side of its jaw to ridiculous proportions. It extends out of the upper side of the jaw and grows up to ten feet long, sticking out in front of the otherwise 15-foot-long animal.

Strangely, this enormous tusk serves very little actual purpose. Narwhals do not use their tusks to fight, nor for self-defense, and not even to scrape ice away from breathing holes in their Arctic habitat. In fact they are practically useless, leading to the notion that they are a secondary sexual characteristic. This is a term for a physical attribute that plays a role in finding a mate, but is not actually used in the act of mating itself (thankfully, in this case). Secondary sexual characteristics are often things that differentiate the male and the female in a species, and examples include a lion’s mane and a male peacock’s long tail feathers.

Female narwhals have tusks as well, but they are much shorter than those on the males, which lends credence to this theory. Male narwhals are also known to rub their tusks together, a behaviour believed to establish social dominance hierarchies — whoever has the bigger tusk makes the rules and gets the ladies. This is all getting a bit too Freudian.

Narwhals are found throughout much of the Arctic Ocean around Canada and Russia. They live closer to shore in the summer and move out to live beneath the ice in winter. The animals breath by keeping holes carved in the ice where they can come up for air every 25 minutes or so. They can dive up to 5000 feet beneath the ocean, which is one of the deepest dives of any marine mammal.

Their tusks were sometimes passed off as unicorn horns in Europe hundreds of years ago. As the unicorn horn was believed to have magical powers, single tusks could sell for as much as the worth of a castle. It was believed that a cup carved from a unicorn horn would eliminate any poison that might be in the liquid poured into the cup.

The narwhal’s cousin, the beluga, has no long tusk, but is just as strange in different ways. Sharing much of the narwhal’s northern habitat, the beluga is distinguished by its white skin.

See, beluga? I told you we still loved you. (Photo by Stan Shebs)

Like all toothed whales, the beluga can echolocate and has an extra organ in its head to help with this, called the melon. The beluga’s melon is particularly large and squashy, giving it a strangely-shaped head. In addition, it is one of the only whales with what you might call a neck. What I mean is that for most whales, the spine in the neck region is fused together, which means the animal cannot turn its head from side to side and always keeps its rigid, streamlined shape. But the beluga is different.

The beluga’s neck is not fused, and the animal can move its head fully from side to side, up and down. This makes its face looser, and the beluga can make facial expressions and can blow air through its sinuses to change the shape of its head like some sort of balloon animal.

If that all sounds rather silly (and it does), you should know that the beluga is something of a silly whale. It likes to play, and both in the wild and in captivity it will fill its mouth with water and spit at other whales or at humans, just for fun. It has a high-pitched voice that led some people to call it a sea canary, and this too contributes, along with the weird head and the facial expressions, to the impression of silly playfulness.

This makes them a popular captive species, and belugas are found in aquariums throughout the world. They used to be taken from Canada, but are now protected from capture there and are instead exported by Russia to dozens of countries — including, oddly enough, to Canada. Most captive belugas were born in the wild and captured, as they do not breed well in captivity. It’s okay, beluga, I don’t make babies well when people are watching me either.

Both the narwhal and the beluga can get trapped in winter if they get caught with only one breathing hole in the ice within their underwater swimming range. In such situations, polar bears may attempt to attack the whales and drag them onto land where they can be killed and eaten, though this can be a dangerous undertaking given the size difference and the possibility of being accidentally speared by a narwhal, which believe me is an embarrassing story for any polar bear to tell at the family Christmas party.

Monodontid distribution. Narwhals live mostly at the extreme northern edge of this range.