Thursday, January 30, 2014

Flickers on a Rainy Day

Rain makes lots of animals behave differently than they normally do. Many birds either take shelter or, like the American robin, head out to forage for drowning worms. The other day (and by other day, I mean several months ago, because I kept forgetting to post this post) during a rainstorm, I was walking with my friend Mona when we noticed a flicker stabbing repeatedly at the ground.

Here is a picture of the end result of what we were witnessing!
According to one source, the Puget Sound Backyard Birds, ants compose about 80% of a flickers diet, and foraging for this tasty insect snack is probably what the flicker was doing as it continually stabbed its beak into the ground! Even if it wasn't looking for ants, most of the flickers diet is insects. During the winter, when insects can become scarce, the flicker consumes berries and seeds. Certainly an unusual diet and foraging behavior for a woodpecker!

Below is a video uploaded by Deepa Mohan of a flicker foraging for food.  As you can see in the video, this flicker is foraging when the weather outside is not so frightful.  I assume that perhaps the flicker we saw was active while it was raining both because the insects would be scurrying around trying to find safe ground, and also probably because the ground was softer than usual.  
Like other woodpeckers, the flicker will nest in holes of trees, but will sometimes nest in the abandoned burrows of birds such as the belted kingfisher or the bank swallow, whose nests are located in holes within the earth.  Below is a picture of a pair of belted kingfishers flying into their nest:

Flickers are pretty common where I live, and they seem to be pretty common throughout the United States!  If you have any great flicker stories or pictures, make sure to send them in or comment below!

Works Cited:

Wednesday, January 29, 2014

Where Does the Canada Lynx Live: Using Common Names to Determine the Native Land of Various Animals

In a PREVIOUS POST, we started looking at different Latin and Greek roots, and how you can sometimes use these to tell a little about an animal, just by looking at its scientific name.  Today, we are going to learn an even more helpful skill: how to tell where some animals live, just by looking at their common name!

This can be a bit of a tough concept, so let's look at a few easier examples to start out.  First off, meet the lynx.  There are three species of lynx alive today, Lynx lynx, L. canadensis, and L. pardinus.  First off, let's look at Lynx lynx, commonly called the Eurasian lynx.  Let's try to figure out where this animal is from by breaking down its name.  Let's first try the "lynx" part of the name.  Can you think of anywhere in the world called "lynx?"  Neither can I, so let's try the first part of the name, "Eurasian."  Can you think of a place called "Eurasian?"  Although maybe not by that exact name, the word "Eurasian" is actually formed from combining the words "Europe" and "Asia," and is a term commonly used in biology, as there is not really a distinct geographic barrier that separates these two continents, as there is between, say, Asia and Australia.  So using this knowledge, where do you think the Eurasian lynx might live?

If you guessed Europe and Asia, then you were exactly right, as you can see in the range map of the Eurasian lynx below!  If you are still having a little trouble with this, go ahead and review the first paragraph before continuing on, and see if you can figure out why you got this question wrong.

Next, let's look at L. canadensis, commonly called the Canada lynx.  We've already established that "lynx" doesn't seem to refer to a place on Earth, so let's look at the "Canada" part of the name.  A quick Internet search comes up with an exotic country by the same name, "Canada."  Let's make a hypothesis about where the Canada lynx makes its home.

If you guessed "Canada," then you are spot on again, as you can see in the range map of the Canada lynx below!  Again, if you are still having some trouble, go ahead and review before you move on again.

Now, the third lynx, L. pardinus, is actually pretty tough.  Called the "Iberian lynx," this Critically Endangered cat is native to only a small bit of the "Iberian Peninsula," in Spain and Portugal.  I knew you guys weren't ready for this one yet, so that's why I skipped it.  Don't worry, you will have another shot at a tough one like this later.

There are actually four members of the genus Lynx, but we've only talked about three so far.  What about the fourth?  And can you tell where all animals live, just by using their common name?  You actually can't always tell, as we can see with Lynx rufus, commonly called the bobcat.  If you break down the name "bobcat" into its component parts, "bo" and "bcat," you can see that neither part of the name refers to a specific place in the world.

I know I'm moving pretty fast, so feel free to hang back for a minute or two if you need a moment for a breather, to recuperate.  Meanwhile, let's take a look at a few more examples.  First off, where do you think the recently discovered Omani owl is from?

As many of you guessed, the country of Oman is exactly right!  Although researchers aren't positive that this is a new owl as scientists haven't been able to closely examine a specimen, initial investigations indicate that this might be a brand new species of owl!

Let's look at the four living members of the penguin genus Spheniscus, Spheniscus mendiculus, S. magellanicus, S. humboldti, and S. demersus.  The first, S. mendiculus, is often called the Galápagos penguin.  Do you think it is named after the Galápagos Islands?  (For those of you who don't know where the Galápagos are, you can consult the map below the picture of the Galápagos penguin.)

Exactly right!  The Galápagos penguins is indeed found in the Galápagos!  The next two, S. magellanicus and S. humboldti, (the Magellanic and Humboldt penguins) aren't actually named for where they live: they are named for famous explorers!
A picture of a Humboldt penguin that I took at the Denver Zoo.
Finally, the African penguin, S. demersus.  You guys have got this by now, I think: where is the African penguin from?
A huddle of African penguins, also at the Denver Zoo.
You guys are getting so good at this, I don't think I need to do any more examples!  I do want to point out real fast that you always need to keep in mind whether the common name of these animals references a place on the globe, or something else.  For example the name of the great-horned owl doesn't refer to the fact that it lives in a place called "great-horn."  It merely refers to the fact that the owl appears to have two little horns on its head!
A picture of the great-horned owl that Anne Price and the folks at the Raptor Education Foundation bring to the raptor shows at the Best Western Denver Southwest dinosaur hotel!
And finally, just like the name of the great-horned owl, the name of the red-tailed hawk doesn't mean that the hawk is from "red-tail," it simply refers to the fact that the hawk has a red tail!

You guys sure did great: now go out there and try and make some new friends by telling them all of your new knowledge!

Tuesday, January 28, 2014

Flocks of Robins and Winter Territoriality

Where I live in Colorado, and in fact across much of North America, the American robin (Turdus migratorius) is a common sight, especially during the spring and summer.  You can often find this bird hopping across the ground, rooting around in the ground for worms.  However, this morning, on my walk across campus, I noticed a flock of about thirty or so robins in a random tree, and couldn't remember a time when I had seen so many robins in one place, not even close.  What was going on?

Just like for a robin, a little digging proved fruitful....or should I say wormful?  "The Great Backyard Bird Count" (GBBC) revealed that during the winter, the territoriality of the American robin decreases dramatically.  Two graphs on the website, which I have included below, help us to understand what is going on.  The first graph, titled "Percent Submissions With Positive Sightings," charts the number of people who see robins.  As you can see, the peak months for robin sightings are between the months of April and July, with a peak in July.  March, as well as August through October, are also pretty good times to see robins, but during the winter months between November and February, robins are not seen as often.

The second graph, titled "Average Number of Birds for Positive Sightings" charts how many robins people typically see together: i.e., if they report a robin sighting, they also report how many robins there were together.  As you can see, April through September are definitely the worst months to see multiple robins together, with October through February being the best time, and a large peak in November.

Graphs are tough: what does this all mean in English?  Essentially, during the breeding season (spring and summer), robins maintain strict territories, which causes them to spread out, with a more even distribution.  This means that you would be more likely to see a robin on a walk through the park, but not several robins in the same place.  During the winter, presumably because their breeding territories are simply too small for them to get enough food, and since it is no longer the breeding season, they abandon their territories, allowing different robins to go wherever they wish.  For whatever reason, probably something to do with mutual protection, they also form flocks.  The forming of flocks also causes the number of individuals per sighting to increase.

Another study conducted by the GBBC (read the full write-up HERE) pertained to snow depth and frequency of robin sightings.  As you can see in the graph below, the likelihood of spotting an American robin with even just a little bit of snow drops quite dramatically.  Similar results were reported for the red-winged blackbird, while birds such as the white-throated sparrow and northern flicker responded to increased snow depth as well, but not quite as dramatically.

For the robin, a bird that typically feeds on the ground, even just a little bit of snow cover might prove to be an issue.  However, other ground-feeding birds, such as the dark-eyed junco, didn't seem to mind the snow anywhere near as much as the robin.  GBBC suggested that other factors must affect the distribution of these birds, such as "weather, diet, and the species' normal range and altitudinal limits."
A subspecies of the dark-eyed junco called the gray-headed junco.  I took this picture of the stuffed animal when we were in Ouray over the summer.
A picture of a dark-eyed junco that I took in my backyard.
The GBBC devotes a paragraph to acknowledge the uncertainties in these results, a humility that I find refreshing and, sadly, not too common on many Internet sources these days.  GBBC looks at the graph below, plotting the snow depth against the likelihood of seeing a house finch, and notes the steady decline, as opposed to the sharp drop seen in the robin graph, or the lack of real pattern seen in the junco graph.  GBBC reports that this would be a pattern not expected if it was access to the ground (or lack thereof) that was causing these birds to move.  Instead, one would expect the sharp decline of the robin graph.  Other factors, such as temperature, could be what is causing birds like the house finch or the house sparrow to move.
A male house sparrow.
A female house finch, silhouetted against the backdrop of the evening sky.
Works Cited:
"Snow Depth Survey." The Great Backyard Bird Count. http://www.birdsource.org/gbbcX/science-stories/past-stories/snow-depth-survey (accessed January 23, 2014).

Stokes, Donald, and Lillian Stokes. The Stokes Field Guide to the Birds of North America. New York: Little, Brown and Company, 2010. (accessed January 23, 2014).

"Winter Robins." The Great Backyard Bird Count. http://www.birdsource.org/gbbcX/science-stories/past-stories/is-that-winter-flock-of-robins-in-your-yard-unusual/ (accessed January 23, 2014).

Monday, January 27, 2014

Winter Trivia Contest 2013 Results

Although I originally planned on having several rounds in our Winter Trivia Contest of 2013, I have decided to save the questions of the other rounds for later.  For now, here are the winners, followed by the answers to the trivia questions!  In first place, we have Carla, who got a 46/50!  As promised, her reward is a blog post with a topic of her choice, which is Top Ten Extinct Prehistoric Crocodilians: look for that post this week!  Second place goes to Alex Lambrecht, with 40/50!  And finally, we have Aidan Cook, who got 24/50!  Here are the answers to the questions!  See you guys for the next contest!


1.  Which of the following is NOT an archosaur? 

A.     American Alligator
B.     Tyrannosaurus rex
C.     Pteranodon
D.    Komodo dragon
E.     Stegosaurus


2.  Though they are called the “Buffaloes,” what is really the mascot of the University of Colorado in Boulder?

American Bison

3.  In terms of their names, name the odd one out:

A.     Dracorex
B.     Guanlong
C.     Triceratops
D.     Hippodraco


4.  What dinosaur is pictured here?  (1 point for a relatively close answer, 2 points for the correct answer.)

Amargasaurus

5.   Is Megalodon still alive today?  Should we trust Discovery Channel?


No, it most certainly is not, and no, we most certainly should not.

6.  Which of the following birds is made up? 

A.     Hammerkop
B.     Screwdriver-bill
C.     Helmeted Hornbill
D.     Shoe-bill
E.      Spoon-bill

7.  Which of the following species of snake is most closely related to the milk snake, Lampropeltis triangulatum?

A.     Corn Snake
B.     Anaconda
C.     Rattlesnake
D.    Kingsnake
E.     Pit Viper

8.  Which of the following is NOT a textbook case of convergent evolution:
A.     Thylacosmilus/Smilodon
B.     Musk Deer/Chinese Water Deer
C.     Mammoth/Mastodon
D.     Gray Wolf/Thylacine

9.  What in the world is THAT!  (1 point for a relatively close answer, 2 points for the correct answer.)

Binturong/Bear Cat

10.  For almost every single constellation that we recognize here on Earth, the stars that make up that constellation almost always have no physical relationship with each other, and just appear to be close together from here on Earth. Name the one major exception, known to the Japanese as “Subaru.”

The Pleiades

11. What shape is wombat poop? 


Cubic

12.  True or False: On average, hyenas scavenge more than lions.

False

13.  Some people think that the discovery of fossilized Protoceratops bones in the Gobi Desert was the inspiration behind what mythical creature?

A.     Dragon
B.     Griffin
C.     Mermaid
D.     Cyclops
E.      Centaur

14.  What’s wrong with this story: “As the giant man used his pocketknife to help him circumnavigate the great jungles of the Amazon Basin, he was startled by the abundant diversity of life.  He saw everything from piranha, macaws, and anaconda, and even saw a black leopard attack a javelina!”

Leopards don't live in South America.

15.  Dermal armor is a feature seen by all of the following except:

A.     Giant ground sloths
B.     Armadillos
C.     Pangolins
D.    Glyptodonts
E.     Ankylosaurs
F.     Clouded leopard

16.  All of the following dinosaurs have been discovered in the Morrison Formation, which has outcrops in Colorado, Wyoming, Utah, and several other states.  All, that is, except for which one? 

A.     Utahraptor
B.     Apatosaurus
C.     Stegosaurus
D.    Camptosaurus
E.     Allosaurus
F.     Gargoyleosaurus

17.  What is pictured here?
A.     Mosasaur
B.     Dinosaur
C.     Pterosaur
D.    Ichthyosaur
E.     Plesiosaur
F.     Dolphin

18.  What strange feature seen in the young hoatzin sets it apart from any other living birds, and forges a resemblance with its extinct ancestors like Archaeopteryx?

A.     Tentacles
B.     Claws on wings
C.     Teeth in mouth
D.     Marshmallows
E.      Flightlessness

19.  How many species of penguin live and breed in the Northern Hemisphere, above the Equator?

A.     Two, the African and Galápagos Penguin
B.     None, everyone knows penguins live at the South Pole
C.     None, everyone knows penguins live at the North Pole
D.    One, the African Penguin
E.     None, everyone knows penguins live in Antarctica
F.     One, the Galápagos Penguin
G.    None, penguins don’t exist

20.  What Triassic animal is pictured here, courtesy of Sam Lippincott?  (1 point for a relatively close answer, 2 points for the correct answer.)

Photo Credit: Sam Lippincott
Tanystropheus

21.  Why is it ironic when people kill bull snakes, mistaking them for rattlesnakes?

A.     Because bull snakes ARE rattlesnakes
B.     Because bull snakes kill and eat rattlesnakes
C.     Because bull snakes are more venomous than rattlesnakes
D.     Because rattlesnakes and bull snakes live on different continents
E.     Because bull snakes don’t exist

22.  A blast from the past: having been around for hundreds of millions of years, what is the name of this “living fossil?”  (1 point for a relatively close answer, 2 points for the correct answer.)

Horseshoe crab

23.  Which of the following is a habitat that you would NOT expect to find a kangaroo in?

A.     The Australian Outback
B.     In the forest canopy of New Guinea rainforests, 60 feet above the ground
C.     Swimming in the shallows of the Great Barrier Reef, consuming kelp and other             oceanic plants
D.    The Australia Zoo
E.    Oh, kangaroos definitely exist, I would just expect to find them in all of these                   locations.  After all, they ARE kangaroos.

24.  Which of the following is NOT a term used in reference to a past mass extinction? 

A.     K/T Event
B.     Cambrian Explosion
C.     The Great Dying
D.     Deccan Traps

25.  Scientific names too hard to remember?  That’s not the case for this “river horse.”

Hippopotamus

Thanks again for participating everyone, and see you next time!

Wednesday, January 22, 2014

Eyes on Ears and Mouth on Toes

Despite the clever if misleading title, we will not be talking about mouths on toes today (although many creatures such as butterflies can taste with their feet).  I just said that to make it sound like the line from the classic song "Head, Shoulders, Knees and Toes" by Bob Dylan.  Instead, we are going to be talking about eyes on ears: eyespots, at least!
A picture of one of the Amur tigers at the Denver Zoo.  See those white bars surrounded by dark fur on the ears of the cat?  Those are the topic of today's discussion.
On the cover of the August/September issue of the National Wildlife magazine, there was a picture of a drinking bobcat, its ears folded back in the posture that some refer to as "airplane ears."  On both of its ears were two white bars that made the ears look a lot like eyes.  I never really paid attention to this pattern on the coat, but once my friend Aidan Cook pointed it out, it got the proverbial gears going.  I remembered that servals also had the eyespot-like patterns as well, but did other cats?  Turns out a lot of them do, with just a few shared throughout the post.  Notice how defined the eyespot is in both the bobcat (top) and the serval, below.

To learn more, I consulted my "Wild Cats of the World" book by Mel and Fiona Sunquist.  The authors state that many cats have this pattern on their ears, "almost as many species" have the ear eyespots that are "poorly defined or absent."  One of the many examples that they include is the lion.  As you can see in the pictures below, lions do have this pattern to a certain degree, but nowhere near as derived as in the serval or the bobcat.  Below we have pictures of a young adult male lion, two of females, and one of a cub, and you can see that none of them have a very well defined eyespot.
Mountain lions also generally don't have it as well defined.  It seems like some mountain lions really don't have that much black on their ears at all, and some have a higher degree of black and white.  Presumably, whatever the function the eyespot serves in other species, it is not as important for the mountain lion, and natural selection therefore does not favor it highly one way or another.
It's a little tough to tell in the picture below, but the sand cat is another one of those cats that has a poorly defined eyespot.
Cheetahs also don't have terribly well defined eyespots.
Yet another cat that does not have very well defined eyespots, the ever fantastic Pallas cat!
I thought I had read somewhere that the eyespots served to help communicate between individuals when they were hunting.  This doesn't make that much sense, though, because most cats are solitary individuals, with the main exception being lions, and we already noted that their eyespots are not quite as specialized.  The Sunquists state in their book that the exact function of the eyespots is unknown, although some scientists believe that they serve as a "follow me" signal to their young, which "may be especially important in low-light conditions."  I assumed that this might mean that the young cats wouldn't have the eyespots, but this is clearly not true, as you can see the photograph of Sochi, the new male Amur leopard cub at the Denver Zoo.  There, you can see that Sochi (named after the Russian city that is holding this years Olympics) also has the ear spots.  So while this doesn't necessarily support the idea of a "follow me" signal to the young, it doesn't really not support it either: it's just something interesting that I wanted to point out.
We already talked about how tigers have a pretty well developed eyespot, but here are two more pictures of tigers to drive the point home.
I can't remember for certain if the picture below was a bobcat or a lynx, but I am pretty certain it is a bobcat, looking at the size of the feet.  (Lynx spend a lot more time in the snow, and therefore have larger feet, a snowshoe-like adaptation to keep them from sinking in.)  This cat, one of many at the Wild Animal Sanctuary, seems to have much smaller feet in proportion to the rest of the body.  Regardless, you can see the well defined eyespots.
The snow leopard, one of my favorite cats, has well defined eyespots as well, which you can kind of see in both of these pictures.
Photo Credit: Masaki Kleinkopf 
The fishing cat is another cat that has these well defined eyespots.
And finally, the Canadian lynx, much like its bobcat relative, also has pretty well defined eyespots!

Works Cited:

Monday, January 20, 2014

The Big Dipper and Orion: Naked Eye Astronomy Lesson II

IN OUR LAST POST, I gave you guys a brief introduction to naked eye astronomy by showing you a bit about how the heavens move every night.  Now, I'm going to have you guys actually apply what you've learned, and go out into the night and try and find a few basic constellations and stars!  We will start with one of the most famous: the Big Dipper!*  But first, pull up the video supplement by clicking HERE, or clicking it below.  We will be consulting it several times throughout this post, so make sure that you have this pulled up!
The Big Dipper is officially an asterism within the official constellation of Ursa Major, or the "Big Bear."  In this case, an asterism is when a portion of a constellation is more famous than the official constellation.  We will talk about another important asterism, Orion's Belt, in just a few minutes!  In the meantime, below is a picture of the constellation Ursa Major.  The Big Dipper appears to be seven very bright stars that make up the tail of the bear.  Besides being an obvious and easily recognizable constellation, the Big Dipper is important for another reason: two of its stars point the way to Polaris, or the North Star!  We talked about Polaris in the last post, so to refresh yourself on the importance of this star, make sure to check out the link I provided above.

At this point, consult Part I of the video supplement, a link to which I have provided at the top of this post.  Part I shows you not only where to look for the Big Dipper in the night sky, but also outlines the constellation, and shows how to use the stars Merak and Dubhe as "Pointer Stars," as guides to locate the North Star.  Below you can see a picture of the same thing.  The constellation of the Big Dipper is outlined in red, with the yellow line being drawn from Merak and Dubhe to Polaris, which has a blue circle around it.

At this time of year, the Big Dipper rests on the horizon at sunset, and not all of it is visible.  It isn't until around 21:00 (9:00 PM) that the entire constellation completely clears the horizon, and doesn't get high in the sky until after midnight.  As we get closer to summer, watch for the position of the Big Dipper at sunset: it will continue to rise high in the sky, and in several months will be at the same position at sunset as it is at midnight tonight.  Furthermore, for the most part, the Big Dipper does not drop below the horizon here in Boulder.  This is because for this latitude, the Big Dipper is a circumpolar constellation, meaning it never sets.  (To learn a little more about what it means to be circumpolar, make sure to check out the last post.)

Next, we will use another constellation to locate two more objects of interest in the night sky.  The constellation is the very famous constellation of Orion.  These days, Orion has already risen in the east by sunset, and is instantly recognizable.  Even in the brightness of many cities, the most prominent stars are still visible.  Below is a picture of Orion, with art of the constellation depiction overlaying the stars.

Now we refer to Part II of the video supplement.  Part II shows us where to see Orion, and also shows us how to use the asterism of Orion's Belt to locate two objects of celestial significance: the bright star Sirius, and the star cluster called the Pleiades.  Just as with the Big Dipper and Polaris, the constellation itself is outlined in red, and the yellow line points the way to Sirius and the Pleiades, which are both circled in blue.

Sirius will not have risen immediately after sunset at this time of year, and you will have to wait for 20:00 or 21:00 to get a nice view of it.  Despite the fact that, at a mere 8.6 light-years, it is only the 5th closest star to the Earth (not including the Sun), it is the brightest star in the night sky when viewed from Earth.  Sirius is a part of the constellation Canis Major, which we will discuss in a future lesson.
You can see Orion in the center of the photograph.  The bright star in the bottom of the photograph a bit to the left is Sirius.
Most constellations are composed of stars that have little to no physical relation to each other.  To see what I mean, refer to Part III of the video supplement.  In Part III, we take a virtual voyage to Alnilam, the center star in the belt of Orion.  As you can see as we get closer and the constellation becomes more and more warped, it is only on Earth and in the nearby Solar System that these stars appear to have any relation to each other.  There are notable exceptions, however, and when it comes to these exceptions, the Pleiades shine brighter than all the rest.  This is where we travel to in Part IV of the video supplement, to Alcyone, the brightest star in the Pleiades.
Another picture of Orion that I took in my backyard.  Alnilam is the center star in the Belt.
Called "Subaru" by the Japanese (yes, just like the car company), the Pleiades is actually an open star cluster, composed of many more stars than can be easily viewed here on Earth, possibly as many as 500!  Located in the classical constellation of Taurus the Bull, almost every culture that could see the Pleiades created some sort of story about them.  Although the stars that are visible within it are not very bright compared to the main stars of Orion or the Big Dipper, it is their close proximity to one another that make the Pleiades instantly recognizable.  You might even be able to see them in the city, but you will have to know where to look, which is covered in Part II of the video supplement.
The Pleiades are the cluster of stars in the center of the photograph.
Next time, we will look at some more of the major constellations in the vicinity of Orion, including the aforementioned Canis Major and Taurus, as well as Auriga and Gemini.  We will also learn a bit about the current location of Jupiter, and the possibility of viewing some of Jupiter's moons!
**I am writing from a latitude of about 40 degrees North, in Boulder, Colorado. The information in this post can apply to anyone within that belt around the world. For example, people in Beijing and Baltimore, both cities around 40 degree North latitude, will see the same thing every night as people in Bursa and Boulder.

Works Cited:

The video and some of the pictures in this post were made using the Stellarium app or the Celestia app.

Saturday, January 18, 2014

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.  
Works Cited:

Tuesday, January 7, 2014

The Shark-Like Edestus: An Interview With Wayne Itano

We've heard from Wayne Itano before, when he told us about the Kremmling Cretaceous Ammonite Locality in Colorado. (To read the post, click HERE.) A physicist at NIST (National Institute of Standards and Technology) in Boulder, Colorado, Wayne also has a hobby interest in paleontology, and is a curator adjoint at the Natural History Museum of the University of Colorado. He has also been doing some very interesting work with a shark-like animal called Edestus, and he graciously agreed to answer a few questions for me regarding this creature! So please join me in welcoming Wayne Itano, as he tell us about this fascinating prehistoric creature!
Scissor-tooth model for Edestus.  Credit Ray Trollwww.trollart.com
The Natural World:  You've been doing some work with an ancient shark-like creature called Edestus. What can you tell us about it?

Wayne Itano:  Edestus is my candidate for the strangest shark of all time. In my opinion, it is even stranger than the better-known spiral-toothed Helicoprion, since it is harder to imagine how the teeth might have been used.  (Read more about Helicoprion HERE.)  Almost the only fossil remains of Edestus are its symphyseal (midline) tooth whorls, which consist of triangular, serrated teeth, joined together at the bases (roots).

Edestus had one tooth whorl in the upper jaw and one in the lower jaw. Since the whorls are bilaterally symmetric (same on the left side as on the right side), they must have been located in the middle of the jaws.

This is a photograph of a specimen of a species called Edestus mirus. It was found in Pennsylvanian-aged deposits (about 300 million years old) of Iowa.
Smithsonian Institution Specimen USNM V 7255. Scale in cm.  To see a better resolution of the picture, click HERE.  Photo Credit: http://collections.si.edu/search/results.htm?view=&dsort=&date.slider=&q=Edestus+mirus+holotype&tag.cstype=all
This is a rare specimen, since it shows both the upper and lower tooth whorls.

The curvature of the tooth whorls makes it difficult to understand how they could have been used.

According to the conventional reconstruction, the two tooth whorls were used as scissors, to cut prey between the two whorls, as in this drawing by Ray Troll.
Scissor-tooth model for Edestus.  Credit Ray Troll, www.trollart.com
To me, this model seems unlikely, given the curvature of the tooth whorls. It seems that the outer teeth are nonfunctional, since they can’t come together, so there would be no reason to retain them.

It seems to me that the teeth would be more efficiently used if the entire head was moved up and down, with jaws fixed, to slash large prey. This is a radically new idea. I have submitted an article for publication elaborating on this idea, but I expect that it may be some time before it gets into print.
New vertical-slashing model for Edestus. Drawing by Gary Raham, www.biostration.com, reproduced with permission of Wayne Itano
My new reconstruction of Edestus, showing the pair of symphyseal tooth whorls, in front, used for slashing prey, and flat teeth in the rear for crushing prey. Drawing by Gary Raham, www.biostration.com, reproduced with permission of Wayne Itano.
TNW: I noticed that you referred to Edestus as being a candidate for the "strangest shark of all time." Is Edestus truly a shark? If not, how do you classify it?

WI: I was using "shark" in an informal sense, as the term is not well-defined for many extinct fish. Edestus certainly falls within the class Chondrichthyes, which today comprises 2 subclasses - Elasmobranchii (sharks, including rays) and Holocephali (ratfish). There is some evidence that Edestus (and also Helicoprion) belong to an extinct line that is closer to the Holocephali than to the Elasmobranchii, but this is a matter of debate. It is safe to call Edestus a chondrichthyan, and I try to avoid the word "shark" when I write a technical paper, or maybe keep it in quotes.

TNW:  Tell us a little bit about your research.

WI:  I am interested in many aspects of paleontology, but for the last 22 years I have focused on fossil sharks, particularly ones from the Paleozoic (older than about 250 million years ago). My interest in Paleozoic sharks dates from 1991, when I found a finspine of a Pennsylvanian-aged shark called Ctenacanthus in a roadcut near the town of McCoy, in Eagle County, Colorado. I wrote an article about this find for the newsletter of the Western Interior Paleontological Society (WIPS) in 1992, which you can read by clicking HERE.
Ctenacanthus finspine found near McCoy, Colorado. Scale in cm.  Photo Credit: Wayne Itano
In trying to identify this finspine, I read everything I could find about Paleozoic sharks. Knowing of my interest in the topic, Professor Martin Lockley of the University of Colorado at Denver loaned me a large collection of shark teeth and finspines from McCoy that he and Karen Houck, also of CU Denver, had found in the 1980s. His paleontological interests had by then switched entirely to ichnology (footprints and other fossil traces), and he gave me the opportunity to write up the fossil shark specimens. I published an article on the finspines in 2003 with Houck and Lockley, which you can read HERE, but I haven’t finished with the teeth yet.

My interest in Edestus started when an amateur fossil collector showed me an unusual shark tooth that he had found at McCoy. After a bit of study, I realized that it was a tooth of Edestus, the first known from the entire Rocky Mountain region. This eventually led to my publishing a rather long paper on Edestus in 2012, again with Houck and Lockley, which you can read HERE.

Recently, I have also published three short papers related to Edestus: one on an Edestus tooth from England, one on an Edestus tooth with abnormal serrations, and one on a tooth from China that had mistakenly been identified as Edestus, but which actually belonged to a more “normal” shark called Carcharopsis.

TNW:  Do you have any future expeditions or research papers in the works?

WI:  Lately most of my “field work” has been in museum collections. In the last few years I have been able to view specimens in the collections of the Yale Peabody Museum, the Natural History Museum (London), the British Geological Society, the American Museum of Natural History (New York), and the New Mexico Museum of Natural History and Science. I have several publications in the works, largely based on fossil shark specimens I have seen in those collections.

One area is the taxonomy (classification) of Edestus species. About 15 species of Edestus have been named, but I think that many of these are synonymous. For example, people have named new species based on unusually small or large teeth, but I think they are just teeth of the same species of Edestus but of different ages. There may be as few as 3 valid species of Edestus.

I have another project where I am examining microscopic scratches on Edestus teeth. I am hoping that I can find feeding-related scratches and that their orientation will provide some clues as to whether the scissors-model or the up-down-slashing model is correct.

-Thank you so much, Wayne, for answering some of my questions!  I look forward to hearing more about Edestus in the future!  Thanks again!-
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