Chiidax the Northern Fur Seal and the Evolution of the Otariids

Late last year, the New England Aquarium in Boston, Massachusetts received Chiidax, an orphaned northern fur seal (Callorhinus ursinus).  However, it was last July that Alaska SeaLife Center first took in Chiidax, after he was left outside the Alaska Department of Fish and Game offices.  A note which was included on the outside of the box that the pup came in said that the pup's mother had died while she was giving birth.  Notice how in the first two pictures of Chiidax below, the pup is covered in an all black coat, a mark of his young age.

After the pups are weaned at around four months old, they molt into their next coat, the cream and brown color of the young juvenile northern fur seal.  Look for those in these next four pictures, taken sometime last fall.  The post on ZooBorns (read that HERE) doesn't say exactly when the pictures were taken, but given that the post was published late last November, these last photos were presumably taken around then.  

When the first post on Chiidax was written on November 23rd of 2013, he weighed 18 pounds, but when he's full grown, he will definitely be a bit bigger: the males, or bulls, of the species can weigh nearly 600 pounds, which is several times more than the females weigh!  The males have to be so large because they create harems of thirty to forty females, and defend them from other males.  The seals are native to the Pacific Coast of the United States, as well as the coast of the Bering Sea in Canada, Alaska, and Russia.  

The last report on Chiidax was in late December, on the 29th.  Below are several pictures that were shared then.  You can see how smooth he looks, and how perfectly adapted for a life beneath the waves this creature is!  

The northern fur seal is the sole extant member of the genus Callorhinus, but there is also a fossil species of Callorhinus.  C. gilmorei is known from the Pliocene Epoch of southern California and Mexico, as you can see in this paper HERE.  Other sources cite another paper, linked HERE, as stating that this genus is also known from Japan, but I was unwilling to pay the fee to read the paper, so that fact remains unconfirmed.  If you have a subscription to this online journal, let me know what you find!

According to the first paper, the eared seals, or the members of the family Otariidae, can be traced back at least to the Mid to Late Miocene Epoch, approximately 11-12 MYA in California, in the form of Pithanotaria starri.  Another taxon, Thalassoleon mexicanus, is known from Mexico during the Late Miocene, approximately 5-8 MYA.  The authors of the paper suggest that between 5 MYA and today, between our time and the time of Thalassoleon, was when fur seal diversification took off, resulting in the eight extant species of Arctocephalus and the extant Callorhinus ursinus, which includes little Chiidax!  The genus Arctocephalus, along with the genus Callorhinus, comprise the extant members of the eared fur seals.  The writers of the paper also suspect that it is during this 5 million year period that the sea lions developed as well.

Things have probably changed a lot in this area of paleontology since this paper was published in 1986, but unfortunately I can't seem to access most of these papers.  Callorhinus gilmorei still seems to be a valid taxon, however, as do Thalassoleon and Pithanotaria.  Hopefully, new fossils will yield more interesting results regarding these creatures very soon!  

Unless otherwise noted, the photo credit for all of these pictures in the post go to ZooBorns, either this post HERE or HERE.  

Boston on Dwellable

Works Cited:

Zoo Babies: Bison

Today, in honor of the birthday of Kevyn Llewellyn, we are going to be looking at a few photos of a baby bison born about this time last year at the Brookfield Zoo in Chicago, Illinois.  Although frequently incorrectly referred to as buffalo, they are simply different animals, despite the outward similarities between the two groups.  If you see something that looks like it could be either a buffalo or a bison, there is a very, very good bet that you are looking at a bison.  Unless something very strange has happened, and in that case, you will be excused for looking foolish when it comes to your knowledge of the bovids.

Anyways, the bison, despite their once immense numbers (numbering in the tens of millions), were hunted almost to extinction in the 1800s, but have made a stunning comeback, with about 20,000 living in protected areas such as National Parks, and a further 500,000 living on tribal lands and ranches.  Nevertheless, their range is vastly reduced from what it once was.  Many people have come to the aid of the bison over the years, including Theodore Roosevelt and a man named William Hornaday, who together co-founded the American Bison Society at the Bronx Zoo in New York in 1905 in order to help protect these wild creatures. Today, they are labeled as "Near Threatened" by the IUCN due to these conservation efforts. 

Today, the bison is the largest North American mammal, but it wasn't always this way.  In fact, it wasn't always even the largest member of the genus Bison in North America!  Ancient ancestors of the North American bison have been traced by paleontologists to southern Asia to about 400,000 years ago, during the Pliocene Epoch.  Once the bison managed to make it across the land bridge into North America, it diversified and evolved.  One species, Bison latifrons, had a horn-span of a whopping nine feet!  Another species, Bison occidentalis (of which I have a scapula!) is thought to be the direct descendant of the modern bison, and evolved sometime during the late Pleistocene Epoch.

While talking bison with Dr. Robert Bakker and Matt Mossbrucker at the Morrison Natural History Museum, I learned that if you are looking at postcranial elements of a fossil bison (that is fossilized bones from behind the head), they are almost impossible to differentiate from each other.  Not only that, but they are extraordinarily difficult to differentiate from cows, too!  As a matter of fact, the species barrier is quite tentative between the bison and domestic cattle, resulting in the domestication of some bison, as well as hybrids, such as beefalo and cattalo.

Photo credit for all of the photos used in this post goes to the website for ZooBorns.  If you like what you are reading, please feel free to follow us here or via Facebook!  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!

Animal Spotlight: Aurochs

This post is the birthday post of Govind Kamath!  Happy birthday, Mr. Kamath!  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!

Over the years, you may have pondered, "Where does my burger come from?"  You probably just meant where was the cow that it came from.  But now here is something else for you to ponder.  Where the heck did the cow even come from?  Do you ever just see wild, black and white cows?  Well, I am here to tell you all about the evolution of the cow.

A Watusi/Longhorn pileup!  They actually crashed into each other, though!  Trust me, I was there, you can even see my sweatshirted elbow in the mirror thingy!

During the Pliocene Epoch, from around 5 to 2 MYA, the planet went through a cooler spell.  The frequent ice ages were a part of this cool spell, as was the most frequent Ice Age.  This colder weather caused many of the worlds forests to decrease in area, which in turn caused the world's grasslands to expand.  This led to the evolution of many large grazing animals, and helped contribute to the Pleistocene Megafauna, often called the Ice Age Megafauna.  One of these large animals that evolved was the Aurochs.

The Aurochs (Bos primigenius), first became domesticated during the Neolithic Age, or the "New Stone Age," probably around 12,000 years ago.  As a matter of fact, two waves of domestication occurred.  As you can see in the map below, there were three different subspecies of the Aurochs; one in northern Africa; one for Europe and Asia; and a third for the mysterious subcontinent of India, as Rajesh Ramayan Koothrappali says in "The Big Bang Theory."  The two different domestications happened with the Eurasian subspecies, Bos primigenius primigenius, and the Indian subspecies, B. p. namadicus. 

These two different domestications of these two different species of cattle led to two different domesticated cattle!  In India, we have the Zebu cattle, which has been given its own scientific subspecies name, Bos primigenius indicus.  The other, Eurasian kind has become the cow that we know today from driving down the street and the Chik-fil-A ads.  While other types of bovines (members of the family Bovidae, a group of ungulates that includes water and African buffalo, yaks, bison, and, of course, cattle) have been domesticated throughout the years, specifically the water buffalo, the south-east Asian Banteng, and the Indian Gaur, it is cattle that have remained the most widely used, for a wide variety of purposes, too.

The Aurochs is now extinct.  The very last recorded female passed away in 1627 in the Jaktorów Forest in Poland.

There are two particularly interesting breeds of domesticated cattle that I would like to now draw to your attention.  Back in December of 2011 on our trip down to Texas to visit my gramma, on the same trip where we visited the Heritage Museum of the Texas Hill Country and saw the Acrocanthosaurus footprints, we also visited the San Antonio Zoo, as well as the Natural Bridge Wildlife Ranch near San Antonio.  This is an awesome place for EVERYONE to visit!  You get to roll down your windows as you drive through a park chock-full of deer, antelope, zebra, and bovines, and you get to drop food for them!  There are also three members of the order Struthioniformes (aka the ratites), like the South American rhea, the Australian emu, and, most terrifying of all, the African ostrich.  The ostriches was absolutely terrifying, and I will talk about them in a later blog post!  But also at the ranch they had two pretty crazy types of cattle!

The first was the Ankole-Watusi, often called simply the Ankole cattle or the Watusi.  Originally bred in Africa, the Watusi was named after the Watusi tribesmen (now the Tutsi of Rwanda and Burundi).  This type of cattle has enormous horns that can span over six feet!  Both genders have these horns, and they can grow from between 1,500 - 1,800 pounds!  Below are some pictures that my family and I took of the cattle walking by our car!

A Watusi.  CHECK OUT THOSE HORNS!

Another Watusi.  CHECK OUT THOSE HORNS!

A baby Watusi!  HOW CUTE!

The second crazy type of cattle is the Texas Longhorn.  The Texas longhorn is, of course, native to the Lone Star State, and reports of the longhorn enduring thirst while still being able to fight off packs of wolves, as well as bears (presumably grizzly bears), from the pioneer times is not uncommon.  The longhorn, like the Watusi, also has six foot horns possessed by both sexes.  According to the Natural Bridge Wildlife Ranch Adventure Guide Book, the longhorn "helped form the basis of the ranching industry of the American West during the 19th century."

A Texas longhorn.  CHECK OUT THOSE HORNS.

Another Texas longhorn.  CHECK OUT THOSE HORNS.

The aftermath of the Watusi/Longhorn pileup seen above!

Whoever said cows weren't interesting!

The Denver Gem and Mineral Show Part 2: The Piscivores (Excepting Penguins)

As we started talking about a few weeks ago, my friend Masaki Kleinkopf and I were able to visit the Denver Gem and Mineral Show at the Denver Merchandise Mart.  Last time, we talked about the giant ammonites, the baby eryops that Dr. Robert Bakker was working on, the gliding Indonesian lizards of the genus Draco and the pterosaurs that evolved from creatures purportedly much like this millions of years ago.  Today, we are going to talk about all of the piscivorous animals that we saw there, except for the fossil penguin that I saw there.  Knowing me, that would easily take up one whole post of its own there.  Keep in mind throughout this post that I'm not certain for all of these animals that they actually eat fish, I just know that the large groups that they belong to often eat fish.  Today, we are going to be looking at the mosasaurs, crocodilians, pterosaurs, sea lions, other fish, sharks, and the dreaded piscivorous dinosaur Spinosaurus.  

MESSAGE FROM ZACK FROM THE FUTURE:  Hello, everyone.  This is Zack Neher.  I have travelled to this post from the future.  I wanted to give you a link to the Homebase for these posts.  I am like Rose Tyler, leaving clues in the form of Bad Wolf.  Except this is not quite like that at all really.  Anyways.  The Homebase for the series is HERE.

Myself next to a gigantic mosasaur skull

I am pretty sure that this is the skull of a mosasaur , anyway.....it looks more like a mosasaur skull than the skull of a crocodilian, if you ask me

A mosasaur jaw, from Morocco by the looks of it

A mosasaur skull (Platecarpus, if memory serves, but it is entirely possible that I am wildly off) in front of a fossil ray

Another huge mosasaur skull

We also got to see the teeth of a piscivorous pterosaur.  The teeth of a piscivore are usually different from those of other carnivorous animals due to their conical shape.  The teeth of the fish eaters, like those of crocodilians and dolphins, are usually conical in shape, to prevent prey from struggling out of their grasp.

The teeth of a piscivorous pterosaurs

Below are the skulls of various crocodilians.

 

 

The skulls of these dudes seem like they should be out of a cartoon or something, they are so weird and comic looking!

Here are a pair of photos of fossilized sea lion teeth, both from the extinct sea lion Imagotaria sp., from the Miocene to Pliocene in the Atacama region of Chile.

Imagotaria sp., from the Miocene to Pliocene in the Atacama region of Chile

Imagotaria sp., from the Miocene to Pliocene in the Atacama region of Chile

Next, a picture of a pair of fossil jellyfish!

Fossil jellyfish!

Next are the teeth of the gigantic, fifty to sixty foot long carnivorous (or actually, piscivorous) dinosaur: Spinosaurus.  Also in the picture are the teeth of another enormous carnivorous dinosaur that lived in the same area of Northern Africa as Spinosaurus at this time of the Cretaceous Period: Carcharodontosaurus, who was not a piscivore, at least not primarily a piscivore, like a penguin, or as Spinosaurus is purported to
be.  (Did you see that alliteration?  My language arts teacher would be most impressed).  I discuss both Spinosaurus and Carcharodontosaurus in two previous posts, which you can look at HERE FOR SPINOSAURUS and HERE FOR SPINOSAURUS AND CARCHARODONTOSAURUS.

The teeth of Spinosaurus.  Actually in this shot, it looks as if most or all of these teeth belong to Spinosaurus.

And now for some pictures of the teeth of Megalodon, the largest shark that is ever known to have lived!  I have talked about Megalodon in the past, click HERE to learn more.

 

Now for some random ones.

It's a fish eat fish world out there

A pair of shark jaws.  I am not certain as I don't remember at all and they are unlabeled, but I believe them to be jaws of sand tiger sharks.  Again, I could be totally off on this!

Top Ten: Extinct Sea Monsters (Part 1 of 5)

Since ya'll kinda get gypped on Wednesdays with the "What Is It?" challenge, I decided that, when I do do the challenge, I will also include a "Top Ten" list.  I mean, come on now, who doesn't like lists?  I know some of my friends would be absolutely and completely lost without them!  So for today's "Top Ten," we are going to take a look at some of the world's most amazing, extinct sea monsters.  This is also up for debate, so if you disagree, just give me a holler!  Also, they are not in any particular order, I just kind of threw them all in there!  So without further ado, here we go, with our "Top Ten:  Extinct Sea Monsters!"

1.  Megalodon - This gigantic relative of the extant great white shark was thought to be simply massive: perhaps even sixty feet in length!  Living the world over, Megalodon stalked the seas during the Miocene and Pliocene Epochs, and only died out during the current Pleistocene Epoch, around two million years ago.  It is thought that Megalodon evolved to such gigantic proportions in order to be able to attack the massive whales that had started to evolve in the cooler seas of the Miocene and Pliocene.  Remember now: if it's a shark, then it's a fish!

A tooth fragment from Megalodon at this excellent restaurant called The Crab Shack on Tybee Island off of the coast of Savannah, Georgia. 

2.  Basilosaurus - A massive, predatory whale (and, therefore, a mammal) that cruised the seas in the Late Eocene Epoch, 40 to 34 MYA, fossil discoveries of this massive animal were reportedly so common in the southern United States during the early 19th century, that bones of Basilosaurus would be used as furniture!  It was first discovered in Louisiana, and is the state fossil of both Mississippi and Alabama.  Basilosaurus has also been found in Egypt and Pakistan.  At around sixty feet in length, the same estimated length of Megalodon, Basilosaurus is thought to have been the biggest creature alive at the time.

COMING UP:

3.  Liopleurodon
4.  Shonisaurus
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. 

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.