The Sloth – A Weird and Wonderful Animal

SlothThe sloth is the only animal I know of that was named after one of the seven deadly sins.

The Sloth is slow. He hangs upside down on tree branches. He has so much algae growing on his fur that he looks green. His claws are so long and curved that walking on the ground is almost impossible. Friends who visited Costa Rica told me that a sloth makes a very good pet (they certainly can’t run away from you like a cat or husky will). But in much of the early literature on the sloth, they were held in remarkable contempt. ‘Cause they’re slow.

You don’t usually think of a scientist making moral judgements about the behavior of animals, but here’s what the great French naturalist Georges Buffon said about sloths in his eighteenth-century book Histoire naturelle:

“… we must speak more of wretchedness than laziness–more of default, deprivation, and defect in their constitution: no incisor or canine teeth, small and covered eyes, a thick and heavy jaw, flattened hair that looks like dried grass…legs too short, badly turned, and badly terminated….Slowness, stupidity, neglect of its own body, and even habitual sadness, result from this bizarre and neglected conformation…These sloths are the lowest term of existence in the order of animals with flesh and blood; one more defect would have made their existence impossible.”

Gee, you’d think Mr. Buffon didn’t like sloths very much, wouldn’t you?

Here are some interesting facts about sloths –

Their body temperature is much lower than most mammals, varying between 82 and 90 degrees.

  • They have lots of teeth, but they are related to anteaters, who have no teeth at all.
  • They sleep about 18 hours a day (upside down), and spend almost all of their lives hanging in trees, where their slowness and greeness makes them very difficult to see.
  • They come down from their trees once every 8 days or so, to deficate and urinate (everything about a sloth is slow).
  • While almost all mammals on earth have seven neck vertebrae, (even giraffes), the two toed sloth has six, and the three toed sloth has nine. Because of the extra vertebrae, the three toed sloth can turn it’s head around farther than any other mammal.

The best place to learn about sloths is at your local zoo, where you’ll find these slow-moving (but maybe not really “lazy”) creatures hanging upside down in the nocturnal house.

I got most of my information from a chapter in the book Leonardo’s Mountain of Clams and the Diet of Worms, by Stephen Jay Gould, who has written some of my favorite books on the subject of animals, paleontology and evolution. He passed away this year, and he will be sorely missed.

Be sure to check out this site about the Giant Ground Sloth, an extinct species from southern California and Mexico, that weighed a ton and had armor plating on it’s shoulders.

Platypus (Ornithorhynchus anatinus) – A Weird and Endangered Animal

Meet the Platypus

The platypus is such an unusual creature that European naturalists thought it was a hoax when the first dried skin was sent to England from the newly explored continent of Australia by Governor John Hunter in 1799. Surely a clever taxidermist had sewn the beak of a duck to the body of a small beaver!

photo courtesy of
Dr. Lloyd Glenn Ingles, California Academy of Sciences.

But when preserved specimens were available for further examination, biologists were even more astounded to find a reproductive tract that was very similar to that of certain snakes and lizards that give birth to live young.

There was speculation that the platypus may be a furry lizard, until it was discovered that the female has mammary glands and suckles her young. But she also lays eggs! The platypus is now known to be a mammal, and belongs to the order Monotrememata, along with the long-beaked echidna and the short-beaked echidna.

The Monotremes are named for the one orifice, called the cloaca, that they use for urination, defecation and reproduction. “Monotreme” means “one hole.” They have this anatomical feature in common with birds and lizards.

The platypus does not have a true beak like a bird, because the bill is actually quite soft and spongy and is covered with a highly sensitive skin. The nostrils are found at the top and near the front, so that the platypus can breath while gliding almost completely submerged in water. This secretive little creature, which is about half the size of a common cat, lives much of it’s life in water, searching for insect larvae on the bottom of streams.

The sensory receptors in it’s beak can sense the small electrical charges emitted by moving larvae, as well as being highly sensitive to touch. In fact, the platypus relies solely on these senses while underwater, because it does all it’s hunting with it’s eyes closed!

The platypus has teeth when it is very young, but sheds them as an adult, and grinds it’s food to a very fine mush with it’s rough tongue against bony plates on the upper side of it’s mouth. The eyes and ears are located in a groove at the side if their heads, and this groove closes tight over their eyes and ears whenever they go underwater.

The males have a spur on the back ankle that is hollow, and connected to venom glands which can be used in defense against predators. These glands are enlarged during mating season, and may be used to defend the male’s territory.

Little is actually known about how the platypus lives in the wild, because they are so secretive. Their senses of hearing and sight are very acute, so they are aware of the slightest movement of people on the banks of their streams. It is believed that the female lays her egg (or two)about a month after mating in the spring, and that the egg hatches about ten days later.

Unlike the echidna, which carries it’s egg and puggle (baby) in a pouch, the platypus digs a burrow in the side of the stream or river, which may be three to ten feet deep. It is believed that the platypus may curl up around her egg to keep it warm, but that she does not stay in the nest with the baby once it’s hatched. Platypus mothers have been known to leave their nesting babies for two or three days at a time, but the babies grow quickly even with their infrequent feeding. The mother continues nursing her offspring for six to seven months. Because these are solitary animals, the young platypus will then need to find a feeding ground of it’s own.

The front feet of the platypus are highly webbed, and they are used as paddles to propel the platypus through water. The hind feet have less webbing, and are used mostly for steering. The tail, which looks a little like a beaver tail except that it is covered with fur, is used mostly to store fat to use for energy during times when food is difficult to find.

These animals are nocturnal, which means they spend the days resting inside their burrows, which they dig into the banks along the rivers. At dusk they come out of their burrows to feed in the stream, traveling a mile or more each day in search of food. At dusk they return to their burrow.

It is impossible to get an accurate count of such a secretive creature, but the platypus has been protected in Australia since the late 1800’s.

Hooded Seal (Cystophora cristata), a Weird Animal

The female Hooded Seal looks like a normal spotted seal, but the adult males are just plain weird.

This large marine mammal carries an inflatable beach ball attached to his head. This pouch is an enlargement of the nasal cavity and hangs down between his eyes and down over his upper lip when deflated.

To inflate his hood, the seal holds both nostrils shut and blows! When fully inflated, the hood is approximately twice the size of a football. As if this were not strange enough, he has the ability to blow a balloon from his nostrils.

He manages this by holding only one nostril closed – the air then inflates a membrane from the inside of his nose, which looks very much like a red balloon. (What do you think happens when he sneezes?)

The video of a hooded seal below shows a baby much too young to have grown the strange inflatable hood. But he’s absolutely adorable!

The obvious question, of course, is why would a seal need this inflatable bladder on top of his head, or a balloon to protrude from his nostril? They have been seen to inflate these structures when disturbed or during mating season, but Judith E. King states, in her book Seals of the World, that these animals are often seen lying calmly on drifting ice, blowing up their hoods and then deflating them in a way that looks as though they are just playing with them.

Of course the only time humans ever see these animals are when they are lying about on top of an ice floe. Most of their lives are spent in water, where the inflatable balloon may have some purpose known only to the seal. (Just for fun, can you think of any other animals that have features that seem silly or even unreasonable to us? Or perhaps write an essay on the possible uses of the Hooded Seal’s hood that we haven’t thought of yet.)

Even though the adult males are a bit odd looking, to say the least, their babies are born with coats that are so soft and beautiful that many are killed during the annual seal hunts off Labrador and Greenland. These pups are called “blue-backs” and are a beautiful silvery blue-gray on their backs, and creamy white on their bellies.

They are born on floating ice off the coast of Labrador and Greenland in the same area as the Harp Seal, another seal pup hunted for it’s coat. While the Harp Seal mother will usually abandon her pup when hunters approach, the female Hooded Seal is much more aggressive, and will stay to defend her baby. A large male is usually nearby, waiting to mate, and he will also defend the threatened pup.

Mating takes place when the pup is weaned, just 3 1/2 to 10 days after it is born, which is the shortest lactation period known among mammals. But during this very short time, the pup will double it’s body weight. The female does not become immediately pregnant after mating, because there is a 3 1/2 month delay in implantation of the egg. She will give birth again towards the end of March.

These seals are solitary animals except during the birthing/mating period when they are found in “families” of two adults and one pup, and again in July and August when they gather on ice floes during the molting season. Little is known about their migrations or lifestyle, since most information has so far come from the sealing industry, and most of the web sites that are concerned with the Hooded Seal concentrate on the inhumane hunting of pups and juveniles for their pelts.

(Just for fun, you might want to search for some of the web sites that discuss the sealing industry and the impact it has on the population of this weird, but wonderful, animal. To do that, just go to www.google.com and put “hooded seal” or harp seal” in the search box. You might want to have an adult with you when you look at these sites, because some of them are rather graphic, (pictures of dead and dying seals), and your parents or teacher may want to check them first).

The Echidna (Tachyglossus aculeatus) – A Weird and Wonderful Animal

New:

Make
a paper mache echidna
. Click the image
for step-by-step instructions!

Echidnas are Monotremes, a type of animal that has been on earth since the time of the dinosaurs.

Echidna
photo courtesy of Dr. Lloyd Glenn Ingles, California Academy of Sciences.

The oldest known monotreme fossils are over 120 million years old, making this the oldest type of mammal on earth. There are only three species of animal in the Order Monotremata: the long-beaked echidna, the short-beaked echidna, and the platypus. Echidnas are found in Australia and Papua New Guinea, and are about the size of a football.

There are lots of weird things about echidnas, in addition to their spines (and no, they aren’t related to hedgehogs or porcupines):

  • They have no teeth.
  • They have long beaks.
  • The opening for their mouth is only 1/4 inch wide, and the jaws do not move up and down.
  • Their rear feet point backwards.
  • Like birds, they only have one orifice for urination, defecation, and reproduction.
  • And they lay eggs!

European scientists had been studying the echidna for more than ninety years before they discovered that this small mammal lays eggs. In 1884 Dr. William Haacke unrolled a captive echidna in hopes of finding a “puggle,” (a baby echidna) in her pouch. Instead, he found an egg, and was so excited about his discovery that he accidental broke it!

The eggs are about the size of a dime, but the puggles are so small when they hatch that they weigh only about 1/7th as much as a dime. The egg is deposited by the mother into a pouch on her belly 22 to 24 days after mating, and it will hatch 10 1/2 days later. The puggle is not fully formed when it breaks out of the egg, but is capable of crawling from the pouch to an area on it’s mother where it can suckle milk that oozes from specialized glands. When the puggle hatches, it’s hind legs are only bumps, and it’s eyes are dark spots beneath it’s transparent skin.

The puggle will grow quickly as it lives in it’s mother’s pouch, and it’s hind legs and feet take on recognizable shapes a few days after hatching, When it is between 30 and 40 days old, it starts to be covered with fuzz, and soon the hair and spines start to grow.

By this time the puggle is so big the mother will have trouble moving with the baby clinging to her belly as she walks. Soon, 50 to 60 days after it’s birth, the puggle will be left in a burrow that the mother digs underground, and it will stay there alone until it’s about 7 months old. The mother will come once every four to five days to nurse, and the baby will drink as much as 40% of it’s body weight at each feeding! (Just for fun, figure out how many pounds you would have to eat at one meal to equal 40% of your own body weight. It’s a pretty big pot of soup, isn’t it?)

At seven months, the mother brings the baby to the mouth of the burrow, feeds it one more time, and walks away. The young echidna is now entirely on it’s own.

Echidnas eat grubs, termites and other small insects, which are caught on the long sticky tongue and sucked into the tiny mouth on the bottom of it’s beak. There are no teeth, and the jaws do not move up and down like most mammals. Instead of teeth there is a ridged area on the palate that looks a lot like a kitchen grater, and a rough place at the back of the tongue. The food is ground between these specialized areas before swallowing. In order to find their food, the echidna has very powerful hearing, and they dig with their extremely strong front and hind legs. If the insect or grub is too big to fit into their tiny mouths, the echidnas break the food into smaller pieces with the end of their beaks. An echidna that has been injured on its beak by a car or other accident will not survive, because it won’t be able to eat.

Echidnas are a protected species in Australia, but they are so secretive that no one knows how many there are. There have been no successful breeding programs to date in any of the many zoos where captured echidnas have been kept. Echidnas in the wild are not social animals. Each individual lives alone in an area large enough to support it, and the babies leave their mother’s territory in order to find an unoccupied place of their own. This also makes it difficult for scientists to count them.

Scientists have found that these “primitive” animals are quite intelligent, with large brains and a learning capacity that is equal to a rat or cat. Captured echidnas can be easily taught to respond to a signal (as long as they know it means “dinner”!) and wild echidnas that have been fitted with radio transmitters by scientists quickly learn the frequency of their own radios and use the sound to know that a scientist is near and trying to find them. (Just for fun, imagine how our lives would be different if we had evolved from egg laying monotremes instead of primates. It would make a very interesting short story, wouldn’t it?)

I learned this information about echidnas from the wonderful book by Dr. Peggy Rismiller called The Echidna: Australia’s Enigma . For more information on this fascinating animal, and the lives of the scientists who study them, look for this book at your local library.

Be sure to visit edgeofexistence.org, where you’ll learn about extraordinary mammals that are close to extinction – including the long-beaked echidna from New Guinea and the short-beaked echidna from Australia.

Weird and Endangered Animals from Around the World

I know this is supposed to be a site with online drawing lessons, but these weird and wonderful animals were “left over” from an old site that doesn’t exist any more. I couldn’t bear to lock them away in the closet, so here they are. I hope you enjoy learning about these strange and bizarre creatures.

Click on the pictures or the blue links to see the complete articles about these wonderful creatures.

Duck-Billed Platypus Duck-Billed Platypus (Ornithorhynchus anatinus). This critter is so weird, many scientists thought it must be a hoax when the first skins were sent from Australia!
Echidna Short-Beaked Echidna (Tachyglossus aculeatus), a spiny, ant-eating mammal that lays eggs!
Aye-Aye Aye-Aye (Daubentonia madagascariensis) One expert called this one of the most distinctive (and rarest) mammals on earth. Find out why.
Hooded Seal Hooded Seal (Cystophora cristata) The seal that carries a balloon on it’s head and blows bubbles from it’s nose.
Sloth Sloth (Choloepus hoffmanni and Bradypus tridactylus)This is the animal that spends all it’s time upside down. Except once every three or four days, when he comes down to go to the bathroom. Everything about this guy is slow!
Pegasus Pegasus (Equus pegasii) OK, we all know Pegasus wasn’t a real animal, but I thought this was a good place to hide him. If you would like a beautiful poster that you can print on your own printer, click on the picture of Pegasus. The full-size printable picture will take a few minutes to load. It looks great in a frame, and you can give it as a gift if you’d like. For other free pictures (of real animals) click here.

The Aye-Aye – A Weird and Endangered Animal

Meet the Aye-Aye (Daubentoniamadagascariensis)

If you shaved an aye-aye and stood him on his hind feet, he would look very much like “Gollum,” the J. R. R. Tolkien character from Lord of the Rings.

This strange little creature from Madagascar has amazingly long fingers on his hands (yes, he’s a primate), and huge eyes for hunting his food at night.

There is only one species of aye-aye now living, although a much larger one lived in the past but is now extinct. Many scientists and citizen’s groups are now working hard to save this animal, which was once considered to be one of the rarest mammals on Earth.

aye-ayeLike the cat during the European Middle Ages, the aye-aye is thought to be an evil creature, and for this reason it is traditionally shot on sight by the human citizens of Madagascar. Unlike the cat, who could survive it’s persecution because of it’s large numbers and wide range, the aye-aye lives only on it’s island, and cannot easily regenerate it’s numbers.

It is almost impossible to see the animals now because they are nocturnal and rare. It is even more difficult to start a successful breeding program in zoos.

When zoologists first studied this animal they were not sure what to call it – it has sharp, continuously growing front teeth like a rabbit or rat, and for this reason they thought the aye-aye might be a rodent. It has ears that belong on a bat, and a tail that belongs on a squirrel; it’s fingers don’t look like anything that you would expect to find on any animal at all. It is now know to be a lemur who lives in moist forests on the eastern side of Madagascar, eating insect larvae, ramy nuts, and some vegetation.

Aye-aye drawingTheir middle fingers are amazingly long and thin, and have been aptly described as “skeletal.” They use this long narrow finger for digging insect larvae from trees. They build nests high in the trees, but often come down and walk on all four limbs on the ground. The aye-aye will mate at any time of the year, and will nurse her young for about seven months..

Gerald Durrell, founder of the Wildlife Trust, wrote an engaging book called the Aye-aye and I, which tells about his experiences in Madagascar while studying and capturing several of these elusive critters for a breeding program. He describes the aye-aye this way: “a Walt Disney witch’s black cat with a touch of E.T. thrown in.”