Antlers Vs. Horns, Part 2: Horns

A horn, unlike an antler, is attached to an animal.  It consists of a bony core, a projection of the bone of an animal, and is covered by a layer of keratin (your fingernails are composed of keratin).  Also unlike an antler, that falls off easily and annually, a horn, if it is broken off, will never grow back the same way.  That is why poachers have to kill rhinos (who have horns) to actually take their horns, as opposed to just letting them fall off.

Many different types of animals have horns.  Let's take a look at a few of these creatures.

The members of the family "Giraffidae," which includes the giraffe and the okapi, both have horn-like things on their heads, called "ossicones."

The members of the family "Rhinocerotidae," or the rhinos, have horns that are composed solely of keratin, and do not have the bone core typical of many horns.  The horns of the rhinos also grow continuously.

Some of the members of the family "Chamaeleonidae," or the chameleons, often have horns projecting out of their skulls, which are covered in a layer of keratin.

And, of course, the members of the family "Ceratopsidae," a group of marginocephalian dinosaurs, have horns projecting out of their skulls. 
Below is a short list of some of the more famous Ceratopsian dinosaurs.

Famous examples of Ceratopsian Dinosaurs (or "Ceratopsians That I Have Heard Of):

1. Triceratops - (Colorado, Montana, and Wyoming, U.S.; Alberta and Saskatchewan, Canada)
2. Arrhincoceratops - (Alberta, Canada)
3. Torosaurus - (Montana, North Dakota, South Dakota, Utah, and Wyoming, U.S.; Saskatchewan, Canada)
   
4. Monoclonius - (Montana, U.S.; Alberta, Canada)
5. Chasmosaurus - (Alberta, Canada)
   
6. Centrosaurus - (Alberta, Canada)
7. Styracosaurus - (Montana, U.S.; Alberta, Canada)
   
8. Achelousaurus - (Montana, U.S.)
9. Pentaceratops - (New Mexico, U.S.)
10. Vagaceratops - (Alberta, Canada)
    
11. Diabloceratops - (Utah, U.S.)
12. Albertaceratops - (Montana, U.S.; Alberta, Canada)
13. Einiosaurus - (Montana, U.S.)
14. Anchiceratops - (Alberta, Canada)
15. Mojoceratops - (Alberta and Saskatchewan, Canada)
16. Pachyrhinosaurus - (Alaska, U.S.; Alberta, Canada)
17. Kosmoceratops - (Utah, U.S.)
18. Medusaceratops (Montana, U.S.)
19. Utahceratops - (Utah, U.S.)

Keep in mind that the tusks seen in elephants, mammoths, walruses, and hippos, despite being superficially similar to horns, are actually greatly enlarged teeth!

Antlers Vs. Horns, Part 1: Antlers

Antlers and horns often look the same, but underneath, they are actually quite different!  Today we are going to look at not only what defines both antlers and horns, but also take a look at some of the animals that have each of them!  All aboard!

Let's start off with antlers.  As defined by the Google dictionary thing, an antler is "One of the branched horns on the head of an adult (usually male) deer, which are made of bone and are grown and cast off annually."  Something that I would like to add is that antlers are unique to the family Cervidae, which includes:

• Deer
• Elk
• Moose
• Caribou (Reindeer)

The only member of the family Cervidae that has horns on both the males and the females is the caribou, frequently referred to as the "reindeer."  However, it has been documented, on numerous occasions, for fertile females from other species of the cervids to occasionally grow antlers, but this is typically due to unusually high testosterone levels. 

The family Cervidae is one of the many families in the order Artiodactyla, frequently referred to as the "Even-Toed Ungulates" (so called because they either stand on two or four toes).  There are around 220 extant (still living, as opposed to extinct) species of artiodactyl, and included within this order are many familiar groups.  These groups, broken down by family, include:

• Camelidae (Camels and llamas)
• Suidae (Pigs)
• Tayassuidae (Peccaries, a close relative of pigs)
• Hippopotamidae (Hippopotamus)
• Tragulidae (Chevrotains, a type of small deer)
• Antilocapridae (Pronghorn)
• Giraffidae (Giraffe and okapi)
• Moschidae (Musk deer)
• Cervidae (Deer)
• Bovidae (Cattle, sheep, goats, antelope)

(Interestingly, the whales, dolphins, and porpoises should be included within the order Artiodactyla, but instead they have been placed within their own, separate order, Cetacea.  This area of the family tree is still messy, and a possible merging of the two orders, Artiodactyla and Cetacea, is being considered, which would create the order Cetartiodactyla.)

Also included within the order Artiodactyla is the extinct family Entelodontidae.  Later today, we will finally be getting around to what was supposed to be the monthly "What Is It?" challenge, but has turned into more of a quarterly or tri-monthly event!  Anyways, we will be announcing the winners of THE LAST CHALLENGE later this evening, after we look at horns!

Daisy Post-Dentist, Yoga Bear, and Giraffe Feeding

So, as you probably know, I am still working to get all of my videos uploaded from our behind the scenes experience at the Cheyenne Mountain Zoo, and to be able to give you guys an overview of what we did at the Cheyenne Mountain Zoo last Friday.  In the meantime, I am going to treat you to a few of these videos that I have uploaded, as well as another video that I made yesterday, and another pretty cool video!

Myself feeding the giraffes

So as I told you before, we were able to feed the giraffes!  Here is a brief video of both Masaki and myself feeding them lettuce.  This is the first time that I have gone to the Cheyenne Mountain Zoo when they have fed them lettuce, in the past it has always been crackers.  This, apparently, is to keep the giraffes healthier.  Makes sense!

Masaki and I Feed the Giraffes

I also uploaded the video from the grizzly bear experience, the one where one of the bears is doing what the keepers call the "Yoga Bear."  There were two bears there, and I don't recall whether it was Emmett or Digger who was doing the "Yoga Bear."  You will be able to see clearly why it is called that in the video, as well as in the picture below!  Apparently this is a behavior that was not taught into the bear, and is an action that has been observed before in wild bears, both in the wild and in wild bears that have been brought into captivity.  This particular bear apparently did it once when he was first brought to the Cheyenne Mountain Zoo from California (I believe), but then didn't do it again for four years.  Now he does it all the time apparently, as the keepers will typically reward that kind of behavior.  Enjoy the video!

The "Yoga Bear!"

The "Yoga Bear!"

Next up is our dog, Daisy, who is a beagle-basset mix.  Daisy went to the dentist's office yesterday morning, where they had to put her under in order to clean her teeth.  When she came back, she was still pretty drugged, and kept falling asleep while she was sitting up, barely able to keep her eyes open!  I hope you enjoy this video as much as I do!  Also, if you listen carefully, you can hear our cat, Chimney, howling for food in the background.  Enjoy!

Daisy the Dog, Post Dentist Appointment

Finally, for those of you who haven't heard about the record-breaking leap made by Felix Baumgartner yesterday, click HERE to learn more!  It was some pretty astonishing stuff!

Cascade on Dwellable

The Denver Gem and Mineral Show Part 1: Giant Ammonites, Burrowing Amphibians and Leaping Lizards

On Sunday, the 16th, my friend Masaki Kleinkopf and I visited the Denver Gem and Mineral Show at the Denver Merchandise Mart.  It was a ton of fun!  They had booths from all over the place, like the Morrison Natural History Museum and the Rocky Mountain Dinosaur Resource Center, an excellent dinosaur museum up in Woodland Park near Colorado Springs!  One of the most exciting things by far was when a pair of women came up to us, and asked if they could film us just going about our business.  They were part of a group making a movie under the working title "Quarry."  It's apparently going to be about American Paleontology, and it looks like Masaki and I may have made the part about why Americans love paleontology, and especially dinosaurs, so much!

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.

Creeper shot of the film crew following us, with a large iridescent ammonite in the foreground.  Notice the distinct chambers.  How magnificent.

We also saw Dr. Robert Bakker there.  After I said hello, he waved me over and said "You're a smart kid.  Can you tell me where the nostrils are on this thing?"  The "thing" that he was referring to was a baby Eryops skeleton that he has been working on, a Permian amphibian that lived in the south eastern United States.  Remains have been discovered in both Texas and New Mexico, and it was a contemporary of Dimetrodon, who most likely preyed upon it.  Upon my examination, I promptly tried to prove his assessment of my intelligence wrong, as I pointed all over the skull in my attempts to locate the nostrils.  Turns out, the nostrils were right where they should be.  They were just confusing because in life, the animal would have been able to cover the nostrils with little flaps of bone, sealing off the nostrils from dirt and such while it was burrowing.  Pretty interesting stuff!

Dr. Bakker's baby Eryops.  The snout is facing the pen in the left of the image, and the two holes that you can see are the orbitals, or the eye sockets.  The googly eyes are explained below.

Another picture from a few weeks ago.  This was taken at the Morrison Museum when my friend Kristie Chua came up to visit.  Dr. Bakker, when asked "Why the googly eyes?"  replied "I put the googly eyes on because I like it." 

We also saw a number of giant ammonites.  Below are a few pictures of the better ones, probably the largest I have ever seen!  The only other possible contender that I can think of was one that I saw at the Heritage Museum of the Texas Hill Country in (you guessed it!) Texas.  That one was a huge, probably five or six feet wide, imprint of an ammonite, right outside the entrance to the museum.  This was the same place that I have talked about before, in my Acrocanthosaurus on the Prowl post.  Great place!  I definitely recommend checking it out if you are ever in the Canyon Lake/San Antonio area of Texas!

The Heritage Museum ammonite.  Perhaps my memory is a bit off.  But I still remember it being incredibly, enormously large.  Perhaps the picture makes it looks smaller?  A mystery.  I suppose I will have to check it next time we go back there now won't I.

The ammonites, in order of amazingness.  Probably about a two, two and a half foot diameter.

Although its size was less impressive, perhaps only a foot or two wide at the most, it was most amazingly iridescent.  There were a large number of them here, but somehow I succeeded in capturing zero great pictures.  Go figure. 

Same story as above.  Not as impressive in size, but amazing in preservation quality.  Check out those septum!

Masaki next to one big ass ammonite! 

And Masaki with another big ass one!  This one a bigger ass!  Bigger ass one?  Bigger one.  A bigger one.

The third really cool thing that we saw there (that I am going to include in this post, at least) were these preserved lizards.  These lizards are from the genus Draco, and are found exclusively in Indonesia.  These lizards are remarkable as they can glide from tree to tree.  Many paleontologists and biologists speculate that this is what the earliest Pterosaurs would have looked like.  For those of you who don't know, Pterosaurs are the flying reptiles that were contemporaneous with the dinosaurs.  Often confused with the dinosaurs themselves, the Pterosaurs were distinct in that they were truly flying reptiles, and not a distinct grouping.  Calling Pterosaurs dinosaurs would be akin to calling a tiger salamander a mammal, on the sole observation that the tiger salamander is a contemporary of a squirrel.  Not so.

One specimen of the Draco lizards....

....and another!

Famous examples of Pterosaurs include (or "Pterosaurs That I Have Heard Of):

1. Anurognathus
2. Darwinopterus
3. Dimorphodon
4. Dsungaripterus
5. Eopteranodon
6. Eudimorphodon
7. Hatzegopteryx
8. Ornithocheirus
9. Peteinosaurus
10. Pteranodon
11. Pterodactylus
12. Pterodaustro
13. Quetzalcoatlus
14. Rhamphorhynchus
15. Sordes
16. Tapejara
17. Tropeognathus

You probably also know the Pterosaurs as the "Pterodactyls."  Probably should have prefaced with that.

A skull of Darwinopterus from the show.  This guy was at the booth for the Rocky Mountain Dinosaur Resource Center, or RMDRC for short, an awesome museum up in Woodland Park.  

The wing of a good sized Pterosaur.  You can see at the bottom of the picture a white round thingy.  That's the ammonite featured in the picture with Masaki, above.  That should help give you an idea of the scale of the wing.  Probably around ten feet or so.  And get this; that whole thing is one enormously elongated pinky!

A fossil pterosaur from the show

Another fossil pterosaur from the show

Anyways, in the Imax production "Flying Monsters" with David Attenborough (FAVORITE.  IMAX.  EVER.), they talk about how many scientists speculate that these lizards of the genus Draco greatly resemble the earliest ancestors of the Pterosaurs.  Initially gliding from tree to tree to snatch flying insects in the air, eventually these small lizards would have become capable of powered flight.  Then, they would have grown larger and larger, until they became the biggest animals to ever take to the skies.  Except for humans, but really.  We don't really count.

Woodland Park on Dwellable

Animal Spotlight: The Okapi

For years, Europeans who traveled to Africa heard tell of a mysterious rainforest animal that they came to refer to as the "African Unicorn."  Apparently, Sir Harry Johnston, the British governor of Uganda, rescued a small group of the native inhabitants, often called the pygmies, from a foreign show person, who, sadly, was most likely going to use his abductees for a circus or freak show.  Upon their rescue at Johnston's hand, they repaid him by giving him information about the animal.

Now we know the animal as the okapi, or Okapia johnstoni, named in honor of Sir Harry Johnston.  Despite the zebra-like stripes on its tail, the okapi is not all that closely related to the zebra, and is actually a very close relative of the giraffe.  Although they may not look super similar, they both have ossicones on their head, similar to the base of DEER antlers.  Ossicones are not only possessed by both the okapi and the giraffe, but also by extinct relatives of both, such as Sivatherium and Climacoceras.

The okapi is listed as "NEAR THREATENED" by the IUCN.  Honestly, I was surprised that it wasn't at least listed as "VULNERABLE," and "ENDANGERED" or worse would not have surprised me at all, given its reclusive nature, its beautiful pelt, and the very fact that humans didn't have much proof of its existence until 1901, when Sir Henry Johnston sent back a carcass to England.  I suppose, however, that its reclusive nature likely helps it to evade human influences a great deal, coupled with the fact that the rainforest that it inhabits is not too heavily tread.  And I guess the fact that it was really made known to science only a little more than one hundred years ago couldn't have hurt either, as it would be soon entering into an age when nature was offered greater protection than in the 1800s. 

Like the COELACANTH and THE MOUNTAIN PYGMY POSSUM, the okapi is often referred to as a "LIVING FOSSIL."  Its habitat consists of montane rainforests in the Central African Republic (CAR) and the DEMOCRATIC REPUBLIC OF THE CONGO (DRC).

The Biggest Carnivorous Dinosaur Part 2: Carcharodontosaurus Vs. Spinosaurus

As I promised yesterday, today we are going to take a closer look at Carcharodontosaurus (kar-kar-o-DON-to-SAUR-us).  Carcharodontosaurus was a relative of Colorado's own Allosaurus.  However, Carcharodontosaurus was four times larger, and found in Egypt, Morocco, Algeria, Libya, and Niger.  At around 46 feet long, Carcharodontosaurus was similar in size to yesterday's Giganotosaurus (pronounced jig-a-NOTE-o-saur-us), and longer than Tyrannosaurus, though Tyrannosaurus was undoubtedly much bulkier.  Regardless, Carcharodontosaurus was a monster-sized killer, and almost certainly had a monster-sized appetite to match.  It is almost a certainty that such an animal would have a fairly large territory, and would have needed to eat a great deal to maintain its fast metabolism, similar to your average teenage dude.

Clearly, such a large predator had little competition from other carnivorous dinosaurs.  Or did it?  As a matter of fact, 95 MYA, North Africa was home to not one, but two monster-sized killers, Carcharodontosaurus, and the even longer, 50 foot (15 meter) Spinosaurus.  (Some not so conservative estimates even place the maximum size for Spinosaurus as 60 feet (18 meters) in length, but this does seem extreme.)

Now, in the modern day, predators can inhabit the same area.  Take the plains of Africa, for example; in many places, lions, leopards, cheetahs, wild dogs and hyenas all inhabit the same area.  There is a clear hierarchy amongst the animals, and each seems to get enough to eat.  However, this is partly because each animal exploits a slightly different set of resources, so contact amongst them is less frequent than if all five of the large carnivores all hunted the same animal, say, the Thomson's Gazelle.  This is a phenomenon known as resource partitioning, and it occurs all over the place in nature, arguably one of the most important factors involving ecology and evolution. Scientists believe that a similar sort of partitioning took place between the two mega-carnivores of Mid-Cretaceous North Africa, with Carcharodontosaurus being a terrestrial carnivore, while Spinosaurus took to the water.  We will conclude "The Biggest Carnivorous Dinosaur" trilogy tomorrow with a look at the environment Spinosaurus was able to so successfully exploit.

A fantastic visual representation of resource partitioning amongst large herbivorous mammals in Africa.  The giraffe, the zebra, and the wildebeest will all inhabit the same area and eat plants, but the types of plants can differ.  Photo Credit: Ted and Gail Neher