Top Ten Mammals That Look Like Something They Aren't (Part 2)

Here is Part 2 of this duo of posts.  For Part 1, click HERE.  What are these two posts about?  Well, we are going to be taking a "Top Ten" look at some mammals that look a lot like something they aren't.  Sometimes, these two animals are fairly closely related: other times, they are quite far apart!  All of these examples will be results of a fascinating phenomenon known as "Convergent Evolution," which is where similar ecological and environmental factors cause two very different animals to evolve in a similar fashion.  So let's dive right in!  But first, this is the birthday post of Joseph Kleinkopf, happy birthday Joseph!

5.  Civets and genets - These two groups of animals are quite possibly some of the most unknown animals that are around today.  Members of the family Viverridae in the order Carnivora, if someone does in fact see one, they usually just assume that they are cats, dogs, or something else along those lines.  The family that the viverrids are most closely related to are, in fact, the cats, but they are also related to they hyenas and the mongooses.

4.  Maned Wolf - The maned wolf is neither a wolf, as its name implies, or a fox, as its outward appearance would indicate.  It is related to both, and is in the family Canidae (the dog family) just like wolves and foxes, but it is thought to be most closely related to the South American bush dog.  Interestingly, although small vertebrate prey is quite important to the maned wolf, it eats a great deal of fruits and vegetables, with the most frequently consumed fruit called the wolf apple.

A slightly fuzzy picture of a brown-morph black bear right outside of our tent-cabin in Yosemite!  Photo Credit: Julie Neher

3.  Black Bear - When it comes to the names of the three bears that inhabit North America, they can be very misleading indeed.  ESPECIALLY the black bear, for the black bear, like many other animals throughout the world (including, of course, humans), has different color morphs.  The black bear is, of course, most frequently black.  However, some of the time, the black bear is actually brown, or cinnamon colored, which is not to be confused with the ACTUAL brown bear (or grizzly bear).  In Alaska and northwest Canada, there is the "glacier" color morph, a grey-blue phase.  But I think my favorite is the "Kermode" color phase, which is exclusive to the coast of British Columbia.  This bear is a creamy-white color, and looks a heck of a lot like the polar bear!  How very, very confusing!

2.  Thylacosmilus - Over the course of mammalian evolution, the marsupials have spat out a large number of look-alikes, or animals that evolved via convergent evolution to appear a great deal like other animals throughout the world.  One of the most amazing of all of these (by far, in my opinion) is Thylacosmilus, a marsupial carnivore from the Miocene and Pliocene Epochs of South America.  Thylacosmilus convergently evolved to resemble the saber-toothed cats of North America.  Unfortunately, following the creation of the Isthmus of Panama that connected North and South America around 2 MYA, the saber-toothed cats like Smilodon moved down the newly-formed land bridge to colonize South America during the Great American Interchange, outcompeting Thylacosmilus in the process.

1.  Raccoon Dog - The raccoon dog is a fantastic case of an animal that is now that it appears to be.  You take one look at it, and you decide conclusively that you are looking at a raccoon, no doubt about it.  Your second and third takes yield the same result.  However, the raccoon dog is not a raccoon, as both its name and appearance might indicate: its a canid, through and through!  Listed as "Least Concern" by the IUCN, the raccoon dog is native to eastern Asia, and is not very closely related to any extant species of dog.  Just a tip, if you are trying to make someone look foolish, showing them a picture of a raccoon dog and having them guess what animal it is is an excellent way to show off your animal-prowess.  Unless they know what it is, in which case you will be the more foolish.

Thanks for joining us tonight for our top ten list!  And remember, if you have a birthday coming up, just email me the date at cuyvaldar123946@gmail.com with the date and your favorite animal, and I will do my best to get a post in! 

Top Ten Mammals That Look Like Something They Aren't (Part 1)

Today, we are going to be taking a "Top Ten" look at some mammals that look a lot like something they aren't.  Sometimes, these two animals are fairly closely related: other times, they are quite far apart!  All of these examples will be results of a fascinating phenomenon known as "Convergent Evolution," which is where similar ecological and environmental factors cause two very different animals to evolve in a similar fashion.  So let's dive right in!  But first, this is the birthday post of Joseph Kleinkopf, happy birthday Joseph! (For Part 2, animals 5-1 of the countdown, click HERE.)

10.  Bear Dogs - As their name implies, the bear-dogs are a group of mammalian carnivores that greatly resemble both bears and dogs.  However, they are neither!  According to The Big Cats and their Fossil Relatives by Alan Turner, they are thought to be fairly closely related to dogs, and more distantly related to bears.  Their remains are most commonly found in North America, although they are also found in Europe, Asia, and Africa.  Temporally, these animals lived during the Miocene Epoch, and are though to have arisen about 15 MYA, and fallen into extinction around 12 million years ago (MYA).

9.  Entelodonts - The Entelodonts, frequently referred to as "Hell" or "Terminator Pigs" greatly resemble the extant (still around, opposite of extinct) pigs and peccaries.  However, they are in a separate family from both the pigs and the peccaries, the family Entelodontidae, but all three do reside in the order Artiodactyla.  Some paleontologists believe that these guys are more closely related to whales and their relatives than pigs, but their exact phylogenetic relationship is unclear.  They inhabited North America and Europe during the Oligocene Epoch, around 34-32 MYA. 

8.  Hyrax - This little guy looks like he would be a rodent, but his true relatives are actually much more surprising!  Weighing between about 5 and 10 pounds, the hyraxes are actually fairly closely related to the members of the family Proboscidea, or the elephants and their relatives!  The extant hyraxes have their own family, Hyracoidea, but their ancient ancestors are thought to have branched into the extant hyraxes, the elephants and kin, and most likely the manatee and its relatives!  Hyraxes are found exclusively in Africa and the Middle East.

7.  Red Panda - The red panda has a long history of uncertainty in regards to its phylogenetic relationship to other animals, as has its namesake, the giant panda.  However, now we know that the giant panda is in the family Ursidae, or the bear family, and the red panda is now classified in its own family, Ailuridae, closely related to the mustelids, raccoons, and more, distantly bears.  For more information about the red panda, click HERE.  For more information about the giant panda, click HERE.

6.  Rabbits and Pikas - Even up until just a few years ago, I had assumed that the rabbits and the pikas were both rodents.  They look a lot like them, and they share the trait of continually growing teeth.  However, the members of the order Lagomorpha, which is the order that includes the rabbits and the pikas, differs from the order Rodentia in that they possess four incisors, as opposed to two for the rodents.  Furthermore, most rodents are omnivorous, while the lagomorphs are almost entirely strictly herbivorous.

For Part 2, animals 5-1 of the countdown, click HERE.

And remember, if you have a birthday coming up, just email me the date at cuyvaldar123946@gmail.com with the date and your favorite animal, and I will do my best to get a post in! 

The Superorder Xenarthra: More Than Meets The Eye

Here's a joke for you: what does the sloth, the armadillo, and the anteater have in common?  Unfortunately it's a pretty terrible joke and not very funny at all, so you might want to keep it to yourself next time you are at a party.  The answer is that they are all in the superorder Xenarthra.  See?  I told you it was bad.

The Xenarthrans are a large group with the lowest metabolic rate of all of the therian mammals (essentially all mammals except for the egg-laying monotremes).  In our Animal Spotlight on the sloth, we discussed the Top 10 sleepiest animals: the sloth was number 2, and the armadillo was right behind it in third place!  But enough about sleep!  There are many very interesting types of Xenarthrans, both living and dead, so let's take a look, shall we?

Before we look at any Xenarthrans in detail, let's just touch upon their spread across the world.  All of the Xenarthrans evolved in the millions of years of isolation experienced by South America prior to the fairly recent formation of the Isthmus of Panama around 3 MYA during the Pliocene Epoch.  During this event, known as the Great American Interchange, many Xenarthrans went north into Central and North America, while many other animals headed south.  We will look at some individual cases of this throughout the post! 

First off, we have the order Cingulata, which includes the extant armadillos, as well as the extinct glyptodonts and pampatheres.  These guys all have something called "dermal armor," meaning "skin armor," which is composed of many epidermal (skin) scales that overlap.  These scales are typically referred to as "scutes," and are made up of bone, surrounded by a covering layer of horn.  Scutes have evolved in many different animals over the years, a fascinating example of convergent evolution.  Below are a few pictures of non-Xenarthran animals that have, or had, scutes!

When an armadillo rolls into a ball, it is protected on all sides by its dermal armor!  Interestingly, the pangolin, a creature once thought to be a Xenarthran but now known not to be, does the same thing!  This is probably at least part of the reason why many people believed them to be related.

Besides the armadillos, the order Cingulata includes the similarly-armored pampatheres, and the much more interesting glyptodonts, both extinct.  The glyptodonts look like a cross between an ankylosaur and an armadillo, and were pretty big, especially compared to the armadillos!  Some glyptodonts went north during the Great American Interchange but, unlike the armadillos, were not able to survive to the present day. 

Next up, we have the family Folivora, or the family of sloths.  Now, we have ALREADY TALKED ABOUT THE EXTANT TREE SLOTHS IN ANOTHER EXCELLENT POST, so we won't really discuss them today.  We will, instead, take a brief look at the giant ground sloths!

At least five ground sloths were successful in their transition from South to North America.  One interesting fact about the ground sloths is that many cryptid hunters (people who believe in Bigfoot, the Yeti, the Loch Ness Monster, etc.) believe the mapinguari, a a mythological creature of Bolivia and Brazil, to be either a cultural memory of a ground sloth from thousands of years ago, or actually a surviving ground sloth or two that managed to survive until very recently, and perhaps is still alive today.  Many parts of the description of the animal match up to what we know, or think we know about these giant ground sloths, including size, the sloping back, long claws, and caiman-like skin.  For those of you who don't know, the caiman is a crocodilian, related to crocodiles and alligators.  This might look weird on a giant sloth creature, but preserved skin of a giant ground sloth shows a type of dermal armor similar to the armadillo and the crocs.  So who knows!

Actually, there is one more sloth thing!  The other day, my friend Kristie Chua sent me something funny.  It read, "If you ever feel uncoordinated, just remember that sometimes a sloth will mistake its own arm for a tree branch, grab it, and fall to its death."  I'm not sure if it's true or not, but it most certainly seems plausible!  Either way, it definitely makes you feel better about yourself!

Finally, we have the anteaters!  Below are a few pictures that I took at the Denver Zoo A FEW MONTHS AGO, and below that we have a picture of a giant anteater skull.  Notice how the lower and upper jaws have been fused together!  Then, below that, is a picture of the tongue of the giant anteater, which can actually be longer than the skull itself!  Enjoy!

 

This birthday post goes out to Sam Lippincott, happy birthday Sam!  If you have a birthday coming up, just email me the date at cuyvaldar123946@gmail.com with the date and your favorite animal, and I will do my best to get a post in!

Why Did The Great Auk Become Extinct?

Question:  Why did the Great Auk become extinct?

Answer:  Primarily because of human exploitation for its feathers and meat.

For those of you who are unfamiliar with the great auk (Pinguinus impennis), this penguin-like creature (a product of convergent evolution) inhabited the North Atlantic Ocean in the Northern Hemisphere, and became extinct mid-way through the 1800s.  The great auk was intensely hunted by humans in European waters for their down feathers, which were actually used in both pillows and hats, as well as for food.  (Not the down feathers, mind you, but the meat of the bird and its eggs).  It wasn't until 1553, around the time that the nesting sites of the great auk had been all but eliminated on the European side of the Atlantic, that the great auk first became officially protected.  In 1775, people who had broken a law forbidding people from killing the great auk for its feathers were actually beaten publicly! 

Following the local extinction (an extinction of a population of animals in one place, but not an extinction of the animal species as a whole) of the great auk in Greenland in 1815, the sole remaining breeding site of the great auk was a small, volcanic island.  Off of the coast of Iceland, the island was dubbed "Geirfuglasker," after the Norse term for "great auk," "Geirfugl."  In 1830, however, the great auk population on Geirfuglasker came under siege by two elemental forces that it had no hopes of combating: an underwater volcanic eruption and a subsequent earthquake, which combined to destroy the island, terminating most of the rest of the great auks.

Those few auks that survived relocated to the nearby island of Eldey.  Eldey was quite easily accessible to man, however, and the last human-led hunt of the great auk occurred on June 3rd, 1844.  On this last great hunt, a pair of these birds were killed, beaten to death, and their egg was destroyed. 

The last sighting accepted by the IUCN to be legitimate was in 1852 off of the coast of Newfoundland in Canada.
The closest living relative of the great auk is believed to be the razorbill (Alca torda), seen below.

Bonavista on Dwellable

Top Ten: Extinct Sea Monsters (Part 2 of 5)

So why did I split this post up into five parts?  Well, originally it was all just one big post, but it was simply too big, like so often happens.  So I will just post the rest of the parts throughout the next few days.  So here is part number two!

3.  Liopleurodon - A member of the short-necked Plesiosaurs, or Pliosaurs, Liopleurodon was the top predator of the Middle and Late Jurassic shallow seas that covered Europe at that time.  Fossils of Liopleurodon have been found in England, France, Germany, and Russia. 

4.  Shonisaurus - Shonisaurus is a fascinating example of convergent evolution.  When similar environmental and ecological pressures went to work on the ancestors of Shonisaurus, and the rest of the ichthyosaurs, as well as the ancestors of the dolphins and porpoises, they produced very similar results in very different kind of animals.  Shonisaurus and the rest of the ichthyosaurs are marine reptiles, while the dolphins and porpoises are both mammals.  Shonisaurus lived during the Late Triassic Period, right around when the dinosaurs were first making their debut.  At least thirty-seven skeletons of this giant have been discovered in Nevada. In fact, Nevada is still a fantastic place to see some of these creatures, especially Berlin Ichthyosaur State Park in Berlin, a few hours outside of Reno (pictured below)!  This is where the first bones belonging to Shonisaurus were actually discovered!  Definitely high on the list of places that I want to go!

Coming Up:
5.  Elasmosaurus
6.  Dunkleosteus
7.  Archelon
8.  Leedsichthys
9.  Tanystropheus
10. Tylosaurus

This post is part of the "Top Ten: Extinct Sea Monsters" series.  For the rest of the posts in this series, click HERE.  

Convergent Evolution: Hesperornis and Penguins

Everyone who is reading this blog, and most people who aren't, have heard of penguins, and know, more or less, what they look like.  However, most people have no idea what a Hesperornis is, which is entirely forgivable.  What is especially interesting about Hesperornis is that it was really the "original penguin," in the loosest sense of the terms.

If not for the captions below each picture, these two animals would most likely be quite difficult to tell apart.  One major difference between the two birds is in the mouth: Hesperornis had teeth, a feature which no modern birds possesses.  Another major, but non-skeletal difference, between the two birds is that Hesperornis died out 78 MYA, during the Late Cretaceous.  Its remains have been found in the United States (Kansas), Canada, and Russia.

The similarities between Hesperornis and modern day penguins is called "Convergent Evolution," a fascinating topic which we will undoubtedly touch upon numerous times.  According to Science Daily, convergent evolution is, "In evolutionary biology, convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches."  In English, when two animals, not necessarily closely related at all, evolve similar features that serve the same purpose.

An (excellent) drawing of the skull of Thylacosmilus

 Another example which we have already talked about is the long, saber-like canines that evolved in both the saber-toothed cats, such as Smilodon, and the South American marsupial carnivore Thylacosmilus.

 This post is part of the "Convergent Evolution" series.  For the rest of the posts in this series, click HERE.

Arthur the Aardvark

Almost everybody has heard of Arthur Read from the popular PBS show "Arthur."  What a lot of people don't realize is that Arthur is an aardvark.  And even more people don't usually even know what an aardvark is.

A fossorial (burrowing, like terrestrial or marine), nocturnal mammal from Africa, the aardvark is an insectivore, its favorite food being termites, and is labeled as "Least Concern" by the IUCN.  The aardvark, as you can see below, inhabits an incredibly large portion of Africa, including South Africa, Ethiopia, Kenya, Tanzania, Uganda, Mozambique, the Democratic Republic of the Congo (DRC), Burundi, Somalia, Angola, and many others.

The aardvark has several important adaptations for its burrowing, insectivorous life style.  Perhaps the most important are the large claws on its front limbs.  These claws enable the aardvark to not only dig out immense burrows for habitation use, but also to dig into termite mounds to extract a meal.  Interestingly, when the aardvark leaves its burrow to dig a new one, the old burrow is often taken up by the African wild dog, where the pups shelter until they are old enough to leave the protection of the burrow.

The aardvark also has thick skin, which keep the termites from biting it, allowing it to feast in relative peace.  A further adaptation to keep insects (as well as dust) out is in its nose: it can close its nose, preventing both bugs and dust from invading its breathing passages.  Finally, another very important insectivorous adaptation is the tongue of the aardvark.  The long, sticky tongue of the aardvark is usually about 12 inches long, equivalent to about one-sixth the length of the animal!  Long, sticky tongues are a fairly common adaptation for termite-eaters such as the numbat (Myrmecobius fasciatus), pangolins (Manis sp.), and the giant anteater (Myrmecophaga tridactyla) among them.

A southern tamandua (Tamandua tetradactyla) shows off its extraordinarily long tongue during an animal demonstration at one of Denver Zoo's teen career days.  Tamanduas are also insectivorous, and clearly also possess an amazing tongue.

Smilodon Vs. Thylacosmilus: The Saber-Toothed Marsupial

Two million years ago, a saber-toothed predator stalked the landscape of South America.  Possessed with long, dagger-like teeth, Thylacosmilus was undoubtedly a terrifying predator of the plains of Patagonia.  This saber-toothed predator would have given even the saber-toothed cats pause, despite the fact that (to paraphrase Obi-Wan Kenobi), "He's more kangaroo now than cat."  Despite superficial similarities, Thylacosmilus was not a saber-toothed cat.  Instead, it was a six foot long, 500 pound saber-toothed marsupial.

A reconstruction of Thylacosmilus by the talented young artist Sam Lippincott.  Interestingly, the super-sized canines of Thylacosmilus grew continually throughout its life, unlike those of Smilodon or Xenosmilus (see below), two of the actual saber-toothed cats.  Photo Credit: Sam Lippincott

The immense canines possessed by Thylacosmilus had previously evolved in both the cat-like Nimravids and the various saber-toothed cats (amongst others), and is a classic example of convergent evolution, a topic, in my opinion, that is one of the most interesting happenstances in nature.  We will hopefully talk about convergent evolution sometime next week.

A mounted skeleton of Xenosmilus, a type of saber-toothed feline, at the Mace Brown Museum of Natural History at the College of Charleston in South Carolina.  I got to visit here in July of 2014, and it was a very nice little museum.  Compare the skull of Xenosmilus with that of Thylacosmilus (below).

Anyways, Thylacosmilus lived during the Miocene and the Pliocene Epochs, from 10-2 MYA.  Up until 2 MYA, South America had been its own, separate land mass, not connected to any other continents since some time during the Cretaceous.  2 MYA, however, something extraordinary happened: the Isthmus of Panama was formed, connecting the two continents.  With this connection, came something scientists have dubbed the "Great American Interchange."  Animals from both continents could move, and spread out into the other continents.  For some creatures, like the saber-toothed cats, this was a good thing; they moved down into South America from North America and dominated the landscape.  For other predators, like the terror-bird Titanis(again, a topic for another time), it was good, for a while; after moving into the southern part of North America, however, Titanis was outcompeted by other predators.  For Thylacosmilus, it was down-right disastrous.  Shortly after the Great American Interchange, fossil evidence of Thylacosmilus entirely disappears, similar to the competition between the dingo and the thylacine that drove the thylacine to extinction on mainland Australia.

The skull of Thylacosmilus on display at the American Museum of Natural History in New York.  Got to see this sucker in person in August 2014, when I visited with my good buddy Zach Evens! 

This is a partial post for the "Convergent Evolution" series.  That means that this post is partially included, but was not made specifically to be a part of that series.  HERE is a link to the Homebase for this series.