Category: Mammals

Binturongs: Known Unknowns


A binturong posted on a platform. Image taken at West Coast Game Park Safari in Bandon, Oregon.

Nocturnal and arboreal, binturongs are difficult to study or observe so there is not much known about this adorable, old-man of an animal. As far as we know, they are the largest member of the civet family. They have a long prehensile tail that they use for steadying themselves as they climb through the trees. They can walk upside down on a tree, hanging from the branches but have never been observed making leaps. Much like opossums, it is doubtful that adults can support their whole weight with their prehensile tail, but the young can.


A binturong staring at the sky. Image taken at West Coast Game Park Safari in Bandon, Oregon.

They are carnivores, consuming birds and small mammals and catching them with surprising speed. They are also capable swimmers and able to dive and hunt for fish. Still, they will also sometimes eat ripe fruit, especially figs and will invade plantations or steal fruit from houses. They eat bananas like they do in cartoons, by squeezing the end and popping the fruit out of its peel.


A binturong licking its nose. Image taken at the West Coast Game Park Safari in Bandon, Oregon.

These animals are usually solitary, although sometimes one or two adults can be seen with young. They defend themselves by biting, with a bite strong enough to sever fingers. They will also growl loudly and spit, with violent movements, scaring off many potential predators.

They are listed as vulnerable due to hunting, trapping for the pet trade and loss of habitat. They have been bred in captivity and the captive animals make a wide variety of calls. You can hear some of these calls here.


A Virtual Tour of Rhinos

Black Rhino

This black rhino, Elly, has been part of a breeding program at the San Francisco Zoo.

It’s probably no surprise to regular readers that I have a soft spot for rhinos. This particular rhino, Elly, single hooved-ly pointed my life in the conservation direction. They are amazing animals. This post is going to primarily focus on black rhinos like Elly here, unless I specify otherwise, although much of the information will be true for most of the rhino species.

For example, all rhinos had enormous ancestors, including the largest land mammal that ever lived, the Indricotherium, which went extinct 10 million years ago.



A life size model of an Indricotherium, an extinct mammal. Image taken at the California Academy of Sciences.

One of the things that animals in this group have in common is their hooves, which have three toes and make a print like the ace of clubs. Notice how this rhino has very similar feet to the Indricotherium model:



A black rhino. Image taken at the San Francisco Zoo.

This group also has a really tough, very thick skin. Their skin is so thick that they are protected from thorns and can travel through dense thorn bush where other animals find it hard to travel. Other animals can then take advantage of the paths created by the rhinos.


Greater one horned rhino

A close up of the thick skin of a Greater one-horned rhino, Gauhati, at the San Francisco Zoo.

This is the skin of a Greater one-horned rhino, which has a scientific name that always makes me smile- Rhinoceros unicornis. On this particular rhino, if veterinarians have to give him an injection, they must do so behind his ear, where the skin is thinnest, or else their needles won’t penetrate the very, very thick skin.

Caring for their skin is a very involved process for black rhinos. First of all, they can be infested with over 20 species of skin parasite, including ticks and worms, which bite their skin and suck their blood. They can also get sunburns and since they don’t sweat, they overheat easily.  Rhinos deal with these problems in a number of ways. The first is wallowing. Rhinos will roll around in mud to cool off and when it dries, it protects their skin from sunburn and parasites. However, baby rhinos won’t go into the mud wallows until they are big enough to climb out and nursing moms won’t go in everyday, probably to keep close to her baby and to keep her teats clean. This is just one of the many sacrifices a mother rhino makes for her young. However, they will roll around in dust.


Apparently, mom's sacrifices don't go unappreciated. Image given to me by the San Francisco Zoo.

Another thing black rhinos will do for skin care is rubbing, which also helps get rid of parasites. They will often use the same rubbing sites for generations and favorite rubbing posts can become practically polished over time. But, all the rubbing and wallowing won’t help them in one particular spot. They can’t quite reach behind the “elbows” of their front legs and rhinos frequently have sores there that can sometimes get infected.

Rhinos also have helpers in their skin care. The most well known is probably the ox-pecker-a neat little parasite eating bird.


An ox-pecker perched on a branch. Image taken at the Oregon Zoo.

These birds will climb all over a rhino and pick at its skin, ears and nostrils and of course, the rhino doesn’t bother them. When ox-peckers feed on antelope, they will take little bits of fur to line their nests, but when they feed on rhinos, all they get is the chance to eat parasites. Still, that’s sometimes enough for them. These ox-peckers will also fly and squawk loudly when danger is near, so they are also a good alert system for the rhinos as well. (While most full grown rhinos have nothing to worry about, lions will sometimes catch older or sick rhinos and calves are always at risk-1 in 6 rhino calves die in their first two years of life. Hyenas are often the cause because they can team up to get around mother rhinos who will aggressively defend their calves.) Unfortunately, ox-pecker numbers have seriously declined in southern Africa because farmers have been using pesticides on farm animals and the birds die from eating poisoned ticks on domestic cattle. The good news is that the birds are now being reintroduced in areas where pesticide use has been reduced.

Perhaps a more surprising rhino helper is a terrapin, a shelled animal closely related to turtles and tortoises. The terrapins live in waterholes where the rhinos wallow and then pull ticks from the rhinos’ skin underwater. Dung beetles also help rhinos, in an indirect way. Remember those sores behind the rhinos’ front legs? A particular parasitic worm loves to dwell is that little safe zone and this worm reproduces in the rhino’s dung. When a dung beetle carries the dung away, it takes the worms away with it. So rhinos have a few helpers to maintain their beautiful skin.

Another feature some rhinos have is a prehensile or partially prehensile upper lip.

A greater one-horned rhino, Gauhati, extending his prehensile lip to receive a carrot. Image taken at the San Francisco Zoo.

This is what Gauhati, the San Francisco Zoo’s greater one-horned rhinoceros looks like with his prehensile lip extended. Here’s what he looks like once he’s pulled his lip back in:


Gauhati after receving a carrot from my husband, Trey. Image taken at the San Francisco Zoo.

Rhinos will pull down branches with their horns and use their prehensile lip to grab twigs and leaves and twist branches until they break. Pretty much any form of bush or shrub within reach is food for a rhinoceros, right up to the thorniest acacia. After a fire on the open plains, rhinos have even been observed eating wildebeest dung, possibly because they were short of the minerals they needed or maybe because they couldn’t find any other food and wildebeest don’t digest grass well.

black rhino

A black rhino at the San Francisco Zoo.

The last rhino feature I’m going to mention is the cause of death for many, many black rhinos. I’m speaking of course of their horn. Rhino horns are made out of compressed hair, but are still incredibly strong. Charging rhinos can poke a hole through a car door. Various cultures have different uses for rhino horn, including for use in traditional medicines or as dagger handles (thanks to education programs, this practice is becoming increasingly rare in Yemen) and since rhino horn is a real status symbol, people pay a small fortune for them. You might recall in a previous post about poaching I mentioned that poachers have high end technology, including helicopters and night vision. If we’re to prevent this animal from going extinct, we have to arm their guardians with advanced technology as well and continue education programs in countries where rhino horn is used. The poaching won’t stop as long as it is such a lucrative industry.

If you would like to help rhinos, there are a number of organizations that you can donate to that provide for rhino rangers, anti-poaching units, equipment for monitoring rhino populations and for breed and release programs. The International Rhino Foundation is a great one. One of the easiest things we can do and my personal favorite is an annual fundraiser put on by the American Association of Zookeepers. It’s called Bowling for Rhinos, and 100% of the profits gets dispersed among various reputable rhino conservation organizations. Follow that link and you can learn where Bowling for Rhinos is taking place near you; enjoy bowling, pizza and friends while saving rhinos. It’s a lot of fun.


Belle and Velvet (background) endlessly grazing in their temporary home at the San Francisco Zoo.

My very first zoo job was “reindeer intern” at the San Francisco Zoo, where I had cool reindeer artifacts and talked to zoo patrons about our beautiful antlered guests. The most common conversation I had went something like this:

Guest: So what are these guys?

Me: Reindeer.

Guest: No, what are they really?

Me: Reindeer.

Guest: No, I mean I know you’re doing the Christmas thing and they have muzzles, but what type of deer are they really?

Me: Reindeer.

Guest: Wait, there really is a such thing as reindeer?

Me: ??

It was actually pretty awesome for me to show them that at least one Christmas fantasy was real-except they don’t fly (yet).

So, reindeer are in fact real. They were domesticated from caribou and are considered a subspecies. There are a few differences between reindeer and wild caribou, but the most obvious one is size-reindeer tend to be about a foot shorter than their caribou cousins.  In a genetic study of Alaskan reindeer and caribou, there were significant differences between these two groups of animals, so although they are capable of breeding with each other, little genetic exchange has occurred.


Holly had a part of her antler that stretch out in front of her nose. When she lifted her head from a food bin, she frequently brought a lot of hay with her. Image taken at the San Francisco Zoo.


Holly was also a master at getting her muzzle off. Image taken at the San Francisco Zoo.

They were domesticated for milk (yes! You can have reindeer cheese!), fur and meat and it is believed that they were domesticated before horses were.

The other topic that frequently came up was the difference between horns and antlers. Deer have antlers, which means that those great big head adornments fall off and regrow every year! Reindeer are one of the few deer species in which both the males and females have antlers.

In our particular group, we had 4 reindeer. Holly was the dominant one and she was a bully. But we spread the food out and she couldn’t be everywhere at once. Belle was second in command. She used to like to play in the water bowl. The others would sip and leave, but she would hit the inside with her hoof and splash in it. By the time she was done, she would often be soaking wet. Peppermint was the smallest female. She would lounge around in the grass and mostly just tried to stay out of Holly’s way. And then there was Velvet. I think he was most peoples’ favorite. I couldn’t tell you why. Maybe because he was clearly the underdog in the exhibit. Maybe it was the way he slowly ambled around the exhibit instead of bounding around like the others. The way he walked reminded me of Eeyore. Maybe the others thought so, too.  I don’t know, but he won many hearts that Christmas.

On a non-reindeer note, Backyard Zoologist is taking a little holiday break to visit family. Posting will continue on the regular schedule of Mondays, Wednesdays and Fridays on January 3, 2011. Happy Holidays!



An African hedgehog is a great animal for school education programs. Image taken at the San Francisco Zoo.

If you’re ever hanging out with a hedgehog, there are a few things you might notice. Despite their spiky look, hedgehogs are actually smooth to the touch if their spines are relaxed and laying flat against their back. They will usually walk around pretty slowly, sniffing constantly as they go, but if they are scared, they can run pretty fast- up to 6.5 feet per second! Most of the time, if you’re hanging out with a hedgehog, they’re sleeping. They’re nocturnal and African hedgehogs like the one pictured above will sleep 18 hours a day, during active months. Still, the 6 hours they’re awake can be a lot of fun. This little hedgehog likes to run around on her exercise wheel.

Hedgehogs are covered with up to 7,000 spines, which is quite a handy adaptation. Each spine has its own tiny set of muscles to raise it straight up if they are startled or to relax it back down when the perceived threat is past. This reflex is so strong that a European hedgehog in the middle of hibernation (when their heart rate drops from 150 to 18 beats per minute and their temperature drops from 93.2 to 39.2 degrees Fahrenheit) will still raise its spines if they are disturbed, even without waking up. To avoid danger, hedgehogs will also roll up into a ball, with their face hidden by their protective spines. This is quite effective. One of the only predators of the European hedgehog is a badger. The only major predator of the African hedgehog is the Verreaux eagle, which will pick it up in its talons, carry it high in the sky and then drop it to get past its defense.

Their spines are not just for defense. For example, hedgehogs are one of the few animals that can eat adders, because adder fangs are shorter than hedgehog spines, so the hedgies are protected from the adders’ venomous bite. Their spines will also absorb the shock if they climb over an obstacle and roll down the other side.

Hedgehogs are born with their spines, but they are wrapped up under a layer of skin, so they don’t hurt the sow when the young are being born (female hedgehogs are called sows, males are boars and the young are hoglets). Hoglets will recognize their mom by scent. Sows are very efficient reproducers. If their den is disturbed within a few days of birth, the sow will eat her young. It’s actually a very practical thing to do. The young will not survive being moved if they are only a few days old, but if she eats them, then she can gain enough energy to breed again. If the hoglets are over a week old when their den is disturbed, she will carry her young to a new den in her mouth.

In Europe, hedgehogs have a pretty close relationship to their English people-friends. People will frequently leave out bread and milk to attract hedgehogs to their yard because they are very helpful and eat garden pests. They are also very cute and fun to watch. Of course, this state of friendship wasn’t always the case. In 1566, they were considered vermin and a 3 pence reward was offered for every hedgehog killed. The same reward was offered for anyone catching a hedgehog milking a cow, as they were believed to be stealing milk from cows at night. If that sounds crazy to you, I can understand why-these animals are not very large. One thought for why this myth existed is because hedgies are often found near cows because they eat the insects that live in cow dung. Another idea is that in the early morning, cows’ udders are full and sometimes the cows can be found lying on the ground. If they leak, hedgehogs might lap it up. A few years ago, one cow was inspected and had a teat that was damaged in a way consistent with hedgehog teeth. But this is probably not a very common occurrence. Today, far from offering a reward for dead hedgehogs, the law actually states that it is illegal to kill a hedgehog with a machine gun or to catch a hedgehog using a tape recorder. (??? Your guess is as good as mine.)

While I’m poking fun at things people used to believe, in the 1658 book “History of four footed beasts and serpents” by Topsel, the following things were believed to be remedies from hedgehog:

-it cured leprosy

-their dried rib skin would help those with colick

-hedgehog ashes cured boils

-powdered hedgehog skin stopped hair from falling out

-using burning hedgehogs as a fumigant “by God’s help” would cure urinary stones

-a hedgehog’s right eye, fried in linseed oil and drunk from a brass vessel, improved ones night vision and

-hedgehog fat “stayeth the flux of the bowels.”

And with that, I will leave you with one last picture of an African hedgehog:

African hedgehog

An African hedgehog. Image taken at the San Francisco Zoo.


Chinchilla Francois actually sitting still for two seconds for this picture. Image taken at the San Francisco Zoo.

This South American rodent is probably known more as a pet today than as the wild animals of the Andes. But they do still exist in the wild. There numbers are so low however, that both the long and short-tailed chinchilla are listed as critically endangered, due to commercial hunting and exportation of their fur. There are now breeding facilities that raise chinchillas both for fur and for pets.

So why chinchilla fur? Well, it is one of the softest things I have personally ever touched. They have about 60 hairs per hair follicle! We have 1. They have 60. And since the square inch of fur right on their neck is the softest, luxury coats are made using only that square inch. It can take anywhere from 100-400 chinchillas to make one chinchilla fur coat. They are very expensive and not really practical. Since chinchillas are from the Andes, their habitat is actually a very cold desert. Given that their habitat is really dry, their fur does not hold up well in rain, so the fur coats are not even functional as a form of protection.

At any rate, chinchillas have this really dense, soft fur to keep them warm in really cold temperatures at high elevations and to keep out parasites. As I just mentioned, their soft fur doesn’t do well in water, so to bathe, they use dust! It seems so counter intuitive, but they take dust baths to get clean because the dust absorbs the oils on their fur. This is why despite their fluffy softness, it is not a good idea to kiss a chinchilla, unless you want a mouth full of dust (Learned the hard way). In their natural habitat, this dust is made of volcanic ash.

Chinchillas live in groups of 50-100 animals.  But don’t let the cute face fool you; these animals can be very aggressive towards one another and anything that crosses them. Especially a mother protecting her young. She will stand on her hind legs and spit directly in the face of an enemy. It’s easy to understand why mom is so protective-she worked hard for her young. Considering how big the animals are, they have a relatively very long gestation period-about 111 days! But it pays off, the babies are born fully furred and with their eyes open. And even though they suckle for about six weeks, they can eat plant food immediately!


Francois, not wanting to sit still anymore, desides he wants to come sniff my camera. Image taken at the San Francisco Zoo.

Special thanks to chinchilla wrangler, Anneliese, for helping me get these shots.

The Mammals With a Big Heart


A lone guanaco. These animals are usually found in herds. Image taken in central Chile.

I spotted this guanaco all by itself while on the road somewhere between La Serena and Valparaiso, Chile and I jumped out to get this shot. I knew it was a guanaco, but didn’t know much about them then except that they and the vicuña are wild camelids (the family containing camels, alpaca, llamas etc.) and that guanacos were the wild ancestor to our domestic llamas (domesticated ~6,000-7,000 yrs ago).

Later I learned that this is probably a male. It’s not very common to see solitary guanacos, but when males are about 5 years old, they will often split off to find and battle for a territory to have their own herd of females, so that’s probably what this guy was doing. Usually there are herds of females and young (called chulengos) together with one dominant male and more interesting, leaderless herds consisting of young males that are not yet ready to attract females and reproduce. While they don’t start out to lead herds of their own until they are about 5 years old, they are ejected from their birth herd by the dominant male at about 1 year old, so the young males all band together. What I thought was cool is that these herds of young guanaco also include old and injured males, so they still have the protection of being in a herd. These all male herds can have up to 200 animals in them. If one member of the herd detects danger, say a puma, it will screech out a very high pitched warning call. And once a potential predator has been spotted, these animals are great at getting away. They have padded feet as opposed to hooves, so they can run fast even on gravel or other rough, rocky terrain. By fast I mean they can run up to 40 miles per hour. They are also strong swimmers. Still, the young are especially vulnerable, even though they can stand 5 minutes after they’re born and follow their mother immediately.

But this guanaco didn’t have the protection of a herd. He was on his own. If he did come upon a territory he was going to battle for, he and the dominant male would try to bite each others legs, which usually ends up in them twisting their necks around each other. Despite the violent nature of these battles, it actually seems comical to me because they look absolutely ridiculous and even do a funny war dance.They will also try to push each other to their knees and they will spit. And their spit is actually juices regurgitated from their stomach. Not just saliva, but actually partially digested food.  That can be aimed and shot up to 6 feet. They do this when they are agitated. So, yeah, um…don’t piss off a guanaco.

How do you know if you’ve pissed off a guanaco you ask?

Well, from what I’ve read, guanaco actually have some pretty standard body signals that will let you know what’s going on. It’s all in the ears and the tail. Here is a list for your convenience:




Straight out or slightly raised=alarmed

Wagging, while nose to nose with another guanaco=greeting


Straight up=normal


Straight back=aggression

So now here’s your test. Did I piss off this guanaco?


The guanaco starts to wander off. Image taken in central Chile.

Hmmm. That’s a tricky one. What about here?


A guanaco giving mixed signals. Image taken in central Chile.

Hmmm. Okay, last one. What about here?


The same guanaco, showing 3 different body signals. Image taken in central Chile.

Huh. I guess this guy just didn’t know how to feel about me. He was sort of alert and sort of didn’t care? And sort of showing aggression?

Anyway, when you look at all of these pictures, do you notice the vegetation around him? These herbivores have some pretty tough plants to chew through. But none the worry, these guys have a 3 chambered stomach that helps them to thoroughly digest these plants and get every last bit of nutrition they need from it. (BUT, they are not true ruminants. No, they only have a psuedo-rumen and are not true ruminants, but “functional” ruminants. You gotta love scientists. The difference, if you care to know is 3 vs. 4 stomach chambers. I suppose that is a pretty big difference. This, by the way, is true of all camelids) They also get most of their water from these tough, prickly plants.

So after all of this, you might be wondering how I chose the title of this post. Well, guanaco hearts are ~15% larger than the hearts of other mammals of the same size. They are literally big-hearted animals.

For more information on these interesting creatures, check out the San Diego Zoos library site.

I Choose YOU!


An electrifying rodent, Pikachus are not as cuddly as they look. This image was created by Victoria Campos. No Pikachu has ever been captured on camera.

Pikachus are generally thought to be very intelligent mammals. Because they are quite crafty critters, all attempts to collect specimens by scientists have failed. Two scientists, who call themselves “Team Rocket,” explain their difficulties.

“We’ve tried everything,” Jessie from Team Rocket said. “We’ve used rubber insulators. We’ve even tried the very controversial psychic attacks. Ground attacks. Nothing’s worked.”

James, the other scientist from Team Rocket was quick to add, “Pikachus are also difficult to find. They are very solitary animals, probably because when too many Pikachus come together, they create major electrical disturbances in the atmosphere. In fact, we believe that if we could gather enough Pikachus in one place, we could alter the entire electromagnetic field of the earth, such is the power of the Pikachus electric abilities. Imagine what types of green energy we could harness if we could learn enough to create artificial Pikachu power.”

Despite not being able to capture a live Pikachu, or even being able to catch them on camera, (Team Rocket’s electrical equipment seems to fail around Pikachus and they are way too quick to have their image captured with manual camera equipment.) Team Rocket has learned a lot about their natural history. One thing that has been a hotly debated issue is the evolution of Pikachus and their closest living relatives, Raichus. Some scientists believe that Raichus and Pikachus share a common ancestor, however Team Rocket has another idea.

“We believe that Raichus evolved directly from Pikachus,” James told Backyard Zoologist. We think that a long time ago, two populations of Pikachus (not a common ancestor) were separated from one another and one of those populations came across a special stone, called a thunderstone, which set off a series of unbelievably fast mutations that ultimately led to Raichus.” This is particularly important, as no other mammal is thought to have evolved this way. If a stone can be a catalyst for the evolution of a species, what other animals could have evolved this way? Only time will tell.

Team Rocket has made some other discoveries about Pikachus as well. They are omnivores, although it seems that their favorite food is apples. Their teeth grow continuously, like most rodents, so they have to constantly chew things.  In addition to being able to produce electricity, they have electroreception, or the ability to detect electricity, which allows them to not only navigate across long distances using the earth’s magnetic field, but also to find mates and prey. Very few mammals have this ability, although the duck-billed platypus is one of them. They have a life span of 3-4 years. They live and reproduce in burrows and the females rear the young by themselves. The young only stay with their mothers for 4 weeks before they are off on their own. If they stay in the area too long, the mother Pikachu will eat her own young. Below is an image of a nesting Pikachu.

Pikachu nursing

An illustration of a Pikachu nursing. Image by Dogsfather from Deviant art.

That is all we know about this elusive creature. Perhaps with time and ingenuity, we’ll be able to better understand this unusual mammal and maybe even gain some knowledge from them that might help to solve our energy crisis.

If you would like to learn more and help take care of homeless domesticated Pokemon, contact your local Pokemon Center.

Lucy the Virginia opossum

Lucy the leucistic Virginia opossum resting peacefully. Image taken at the San Francisco Zoo.

Where do I even begin with opossums? They are one of my favorite mammals and I believe they are a little misunderstood sometimes. They’re very important animals, that eat carrion (dead stuff), garden pests such as snails and slugs, snakes and even over-ripe fruit (preventing it from rotting), so they play an important role in our ecosystem. Furthermore, if we took opossums out of the ecosystem, the niche they fill is easily taken over by skunks, raccoons and rats. However, opossums are probably preferable (although I do love skunks, raccoons and rats), because they don’t dig up your yard and even cooler, they have an immunity to rabies and distemper!

Speaking of immunity, these adorable creatures are immune to the venom of rattlers, water moccasins and copperheads. They do have to worry about parasites and interestingly enough, frost bite and the often resulting gangrene. They used to live only as far north as Virginia and Ohio, but with the arrival of Europeans, these animals were introduced farther north (up to British Columbia) as small game after WWII. However, since they evolved in warmer climates (a long time ago, as they were around with the dinosaurs), they are ill-equipped to deal with harsh winters, being unable to hibernate and having naked hands, ears and tails. Yet these hardy animals survive there and in fact do quite well, frost bite aside.

One thing I find particularly endearing about opossums is their hands and how they use them. They actually have opposable “thumbs” on their back feet, so they are excellent climbers (and swimmers) and sometimes use their hands to eat.

Lucy the opossum, showing us her hand

Lucy the opossum showing us her hand. Image taken at the San Francisco Zoo.

They also use their hands to groom their faces, kind of like kitties. This is Henrietta, my all time favorite opossum grooming herself:

I can see why some people would be intimidated by opossums. They do have more teeth than any other mammal in North America (50, to be exact) and if they are scared, these relatively peaceful animals will expose their teeth and hiss, as a first line of defense. To see what their teeth and skull looks like, here is a site with a 3D opossum skull that you can rotate around. It’s pretty cool. While I have been hissed at, most often I see opossums using their teeth like this:

That is Henrietta again, very gently taking and nomming grapes from my hand, with the most adorable smacking sound.

Now I mentioned that they will hiss and show their teeth as a first line of defense, but if that should fail, their body has an automatic reaction that is also pretty neat. Have you heard of the expression “playing ‘possum?” These cuties will actually slip into a comatose state, with their mouths open, drooling and everything, to appear dead. They will even emit a foul smell from their anal gland and their heart and breathing rates drop. It’s quite convincing and many predators, such as foxes and bobcats, will leave them be.

After all of this, I think the most interesting thing about Virginia opossums is their mating and reproduction. They are the only marsupial found in the United States. The male opossum courts a female by clicking its teeth and following her around. At some point the female accepts his appeals and he mounts her in a typical mammalian fashion. Then they will fall to their right side. Yes, almost always to their right side. If they stay upright, or if they fall to their left side, then the female is not likely to be inseminated. The opossum penis is forked, which is probably why people used to believe that male opossums would inseminate the females through their noses and that the females would then sneeze their babies into their pouches. Yes. People really believed that. Their sperm are also paired and can only swim properly in pairs. If you separate a pair of sperm, then each sperm just swims in circles. I could not make this shit up.

Alright, the male is now done and everything else is up to the female. Like most marsupials, she has a pouch and the incredibly tiny young are born shortly after fertilization and climb into her pouch. However, for opossums its not quite so easy. Up to 25 small opossums are born. They are all so tiny that you could fit all of them together in a teaspoon.  And they will all race to mom’s pouch, because in an extreme case of survival of the fittest (not the Darwinian definition of fitness, but in terms of physical strength and endurance) only 13 will be able to attach to a nipple. (In “North American Wildlife” by David Jones, he calls it the “world’s cruelest game of musical chairs.”) That’s right mom only has 13 nipples and once a young opossum attaches to a nipple, it swells up and they are essentially locked on until they are developed enough to leave the pouch (about 2 months). The rest of the babies, if they even make it into the pouch, just die. While we’re on the topic, the Virginia opossum is one of the few mammals that has an odd number of nipples. She has 12 nipples in a circle, and then one right in the middle. They are truly unusual mammals.

One last thing that I think is interesting. While opossums do have prehensile tails, adults cannot hang by their tails, contrary to popular belief. They use their tails to aid in climbing and they will collect nesting material with them as well. On the other hand, young opossums can hang by their tails.

baby opossum

Baby opossums hanging from their tails. Image taken by Frank Lukasseck/Corbis.

While this picture is not mine, I simply had to include it because it is unbearably adorable. And just for shits and giggles, I’ll add just one more photo of my princess, Henrietta. I want to point out that Henrietta was rescued from her dead mother’s pouch and was a wonderful part of the San Francisco Zoo’s education programs. She could have just died and so I’d like to point out that if you see a dead opossum, it might be in its comatose state or it might still have living young in its pouch, so it’s important to contact the professionals to check it out.

Henrietta the opossum

Henrietta the opossum. Image taken at the San Francisco Zoo.

So there you have it. The Virginia opossum. I would like to note that throughout this post, I am always writing about the Virginia opossum and not any other opossum species. As you can see, these animals are non-threatening, clean, adaptable and beneficial survivors. I hope you all can appreciate them as much as I do. To learn more about them, here is a fantastic site by the Washington Department of Fish and Wildlife and here is a cool site to help you find opossum tracks.

Duck-billed platypus

A duck-billed platypus specimen at the California Academy of Sciences. Part of their extreme life exhibit.

The duck-billed platypus, aside from having a hilarious name, has long been a fascination of scientists.  Upon first examining a platypus specimen, some scientists thought the animal was surely a hoax, specifically that it was several animals sewn together.

The platypus is probably most known as one of the few monotremes, or egg-laying mammals (they are still considered mammals because they produce milk, although platypus have no nipples). But in addition to its relatively weird reproductive strategy, this animal has all kinds of unique characteristics for a mammal. For example, when diving the platypus can close off its nostrils and cover its eyes and ears, but then how is it able to navigate under water with its senses shut down? Well, the answer is in their funny looking bill; they have a sixth sense. This sense is called electroreception, which is also found in cartilaginous fish like sharks and rays. In the platypus bill, there are small electricity-detecting pits, which they use to find small prey buried in the mud by the electrical pulses given off by the prey’s muscles. There is no hiding from a platypus. Further, an adult platypus has no teeth, but uses ridges and sometimes gravel it picks up to chew the food once it catches it.

Male platypus are also one of the few venomous mammals. They have venom glands in their thighs that are attached to venomous spurs on their hind legs. The females have this spur, but lose it in their first year. You can actually tell how old a young platypus is by how long its spur is. The venom is strong enough to kill a dog, and has caused a range of symptoms in humans, up to paralysis of an entire limb.

platypus spur

The venomous spur of an adult male platypus. Image taken at the California Academy of Sciences.

So despite their comical appearance, these animals are nothing to laugh at.

comedy club

A sign for a comedy club in Toronto, featuring one platypus.

Oh. Sorry little guy. I stand corrected.

One last thing. I have noticed that a number of Christian organizations are suggesting that the platypus, which appears to have features from several different animal groups, is evidence that evolution must be incorrect.  Therefore, I’m including this link which discusses the decoding of the platypus genome and how it sheds light on not only platypus evolution, but mammalian evolution, as monotremes share genes with their reptilian ancestors.

And if you like, you can adopt a platypus from the World Wildlife Fund.