Migrating Fish: Anadromous or Catadromous?

According to Merriam-Webster's online edition, the word "anadromous" means "ascending rivers from the sea for breeding."  This word is almost always used in conjunction with fish, as they are the main type of animal that do this.  There are a number of fish that are defined as anadromous, but of particular import for us are several types of salmon, including the Coho, steelhead, Chinook, and sockeye salmons.

You don't have to be in a school (of fish) to hypothesize that there might be a group of fish that behave in an opposite manner from the anadromous fish.  "I'll take the bait," you're saying.  "What's the opposite of an anadromous fish?"  Let's break the word apart.  First, we can break off the root "ana," a Greek root which means "up."  For you chemistry buffs out there, you might have felt an electric current running up your spine, as you've probably thought of the word "anion," a term used to describe an ion that contains more electrons than it does protons, giving the atom an overall negative charge.  If you follow the flow of my logic*, you might be thinking of the opposite of an anion: a "cation," or an ion that contains fewer electrons than it does protons, giving the atom an overall positive charge.  So judging from this chemistry example, you can either conclude that, A) The opposite of anadromous is likely something along the lines of "catadromous," or, B) I give really long and tangential comparisons that are neither helpful or correct.  Fortunately for you guys, option A is the correct one.  The opposite of an anadromous fish is, indeed, a catadromous fish.  To learn more about the life cycle of a catadromous fish, let's travel to the eastern coast of North America, and meet Anguilla rostrata, the North American eel.  (And yes, eels are a type of fish.)

To learn more about the life cycle of the North American eel, I consulted the website of the Penobscot River Restoration Trust.  According to the Trust, mature Anguilla rostrata leave their brackish or freshwater homes and migrate to the Sargasso Sea in the fall.  The Sargasso Sea is not actually a distinct sea, but instead a large region of the Atlantic Ocean where a holopelagic species of seaweed called Sargassum reproduces.  The term "holopelagic" simply refers to the fact that, unlike other seaweeds, Sargassum does not require the presence of the ocean floor to reproduce, and can instead reproduce while just floating around in the ocean, or in the pelagic zone.  In turn, the pelagic zone is simply defined as an area of a body of water that is neither close to shore nor close to the bottom.  I remember when my family and I went on the Tybee Island Ecology Tour with Dr. Joe Richardson several years ago in Georgia, Dr. Joe commented on the large amount of Sargassum that was on the beach that day.  I've recently talked with Dr. Joe about the Sargassum, as well as the North American eel, and this interview will be the subject of our next post.

As winter rolls around, the adult eel spawns....then dies.  Sad day for the grown up eels.  Their eggs, however, hatch after a few days, and the young develop into a larval stage (which are then called leptocephali) that simply drift around for a few months.  Their days of floating casually around the ocean end as they enter the Gulf Stream, and are carried north towards North America.  Once the larvae find themselves near the continental shelf, they transform into what are called "glass eels," miniature little eels that, as you could probably guess from the name, are transparent!

It's not over for these eels yet, though!  Next, the young reach the estuaries, transitional areas along the coast where the rivers meet the sea.  Once the summer rolls around, it is in the estuaries that the eels enter the next stage of their life.  In this phase, the young eels are called "elvers," a name for a juvenile fish that is specific to eels.  After making their way into their adult habitat, they finally develop into their adult morph, where some eels stay for 8-25 years before migrating back to spawn in the sea!  

So there's a perfect example of a fish with a catadromous lifestyle.  Or, rather, nearly perfect.  In more recent years, scientists have begun to discover that while some adult North American eels fit well under the catadromy heading, other members of the exact same species simply stay in the estuaries to mature, while still more travel back and forth between the estuaries and the fresh water habitats further upstream!  This has caused many scientists to reconsider the stance of a purely catadromous lifestyle for these eels, and revise their description to "facultative catadromy," which essentially means that these eels seem to be able to choose whether or not they want to commit to a fully catadromous lifestyle.  But what about an anadromous fish, like the Chinook and Coho salmon that we mentioned earlier?  Don't worry, I'm not going to flounder: I know that if you're still reading this, then you're probably hooked, and want to hear more.

Speaking of hooked: my fishing contact Larry Quilling with a spring Chinook salmon in the Trask River in Oregon.  Check back soon to see an interview with Larry about his experiences fishing salmon!  Photo Credit: Larry Quilling

When it comes to the lives of several of the species of Pacific salmon, the saying "When the going gets tough, the tough get going" really applies quite nicely.  One of the keystone species in the American northwest, the annual "salmon run" is incredibly important to the functioning of the ecosystem.  During the salmon run, millions upon millions of these fish travel upstream to their breeding grounds.  Some travel up to 900 miles, as is the case for many Chinook and steelhead salmon who make their home in Idaho, as seen below.  The Chinook females also build an enormous nest, called a redd, that can be one to four feet deep and around six feet in diameter!  

Here we have another one of my fishing contacts, Wallace Westfeldt, with a steelhead in Idaho.  Wallace was also kind enough to help me out a lot, and we will also be seeing an interview post with him soon!  Photo Credit: Wallace Westfeldt

Another fascinating thing to note is the incredible transformation of these salmon, especially the males, as they travel upstream.  My personal favorite is the transformation of the sockeye salmon, whose changes can be seen in the picture below.  

With their fisshin accomplished, most salmon species die once they reach their spawning areas, just like the North American eel.  However, unlike the Pacific salmon, some individual Salmo salar, or Atlantic salmon, live to tell their gilling tale to future generations of salmon.  Not all Atlantic salmon die from their ordeal, as the bodies of these fish don't deteriorate post-spawning.  For the Pacific salmon, their method of reproduction is sometimes referred to as "semelparity," a situation in which the organism is physiologically incapable of spawning more than once prior to kicking the chum bucket.  The opposite of semelparity is iteroparity, where the animal can reproduce multiple times prior to death.  Almost all extant vertebrates (and, indeed, a large portion of extant organisms) are iteroparous, including us humans.  Notable examples of this semelparous lifestyle include some types of spiders, the genus of marsupial mice Antechinus, some types of bamboo, the aptly named century plant (or agave), and of course, several types of salmon.  

So in the course of this blog post, I've thrown a whole lot of new words at you.  Let's stop to reconsider them real fast, in the order that they were introduced in the post.

• Anadromous: Refers to a type of animal that goes from the sea into rivers to breed.  Many types of salmon fit this ticket.
• Catadromous: This term refers to a type of animal (typically fish) that goes from rivers into the sea to breed.  An example would be the North American eel (Anguilla rostrata).
• Holopelagic: An organism that remains in a pelagic area for its entire life.  An example would be the Sargassum seaweed.
• Pelagic: An area of a body of water that is neither close to shore nor close to the bottom.
• Leptocephali: A name given to the larval stage of eels.
• Glass Eel: The next stage in the life cycle of an eel, following leptocephali, but preceding the elver stage.  
• Estuary: The transition zone between the ocean and a river.  The portion of a river that is saltier than the rest of the river, but not quite salty enough to be the ocean, and is influenced by the tides.  Essentially, the last portion of a river prior to its arrival in the ocean.  
• Elver: A name referring to an eel in its postlarval stage following the leptocephali and glass eel stages.  
• Facultative Catadromy: A term used to refer to an animal that can choose (facultative) whether or not they want to commit to a fully catadromous lifestyle.  A good example is the North American eel (Anguilla rostrata).  
• Keystone Species: A species of animal that is integral for the functioning of a healthy ecosystem. 
• Redd: A nest made by a fish, such as that of the female Chinook salmon pictured above.
• Semelparity: A term which refers to organisms that can only reproduce a single time prior to their death.  Examples include some spiders, several types of Australian marsupials and salmon.
• Iteroparity: A term which refers to organisms that can reproduce many times prior to their death.  Examples include humans, pigs, and the Atlantic salmon.

That's a lot of new vocab for just one post!  While I'm not sure if we will be returning to the life cycles of eels again in the future, make sure you hold on to the terms "anadromous" and "catadromous" (as that was the whole meaning of this post), as well as "keystone species."  We will hopefully be taking a broad look at several keystone species sometime in the near future!  And make sure to check back in during the next several days so you can hear from Larry Quilling, Wallace Westfeldt, and Dr. Joe Richardson!

*I'm sorry, I am really proud of that pun.  Not ONLY does it work in the context of fish in streams, but it also works in the context of electric current and chemistry.  Dang I'm good.

References:

We're Back (Again)!

All righty, team: it's been awhile.  I've been pretty busy, but I'm hoping to get back in the blogging world very shortly, as I've got all SORTS of terribly exciting things to share with you from the classes I'm taking!  In the next few weeks, we should be learning about at least one thing from each of the classes that I'm taking this semester, including lactose intolerance (General Biology), "The Gray Wolf and the Prairie Dog: A Discussion of Keystone Species" (Environmental Systems: Climate and Vegetation), and "Evidence for Continental Drift" (Intro to Geology).  (If you know me, though, you know I rarely keep my promises when it comes to upcoming posts, I have the attention span of a squirrel.)  We will also be branching out a bit, too.  Branching up, I suppose, is more accurate: right up into space!  I am enrolled in a fantastic class called "Ancient Astronomies," taught by Professor John Stocke, which is a study of how ancient peoples used the heavens for calendars, religion, and much more.  It is super interesting, and really gotten me interested in space!  So in the next few weeks, you can also stay on the lookout for "Altair and Fomalhaut: Cold's Cottonwood and Big Woman," as well as a post about Venus!  Finally, I am hoping to combine what I've learned in all of my classes to tell you all about what I've learned regarding photosynthesis/chemosynthesis, life at the hydrothermal vents in the deep ocean, and what scientists are learning from these sun-independent ecosystems to predict whether life might exist on other planets and, if so, where to find it!  Tonight, I was researching the Chumash Indians of Santa Barbara and the Channel Islands of California for an upcoming paper for Ancient Astronomies, when I came across a word I didn't recognize.  The word, "anadromous," was used to describe a type of fish that was a mainstay in the diet of coastal tribes of Native Americans in California.  Unfamiliar with the word, I decided to look it up, and share it with ya'll!

A picture of Venus (the little glowing dot below the moon that isn't a street lamp) and the moon (which if you couldn't find before then you'll be extra lost now since then you couldn't find Venus).

A picture I took of the moon and Venus.  It looks blurry because it is.

What I got was more than I bargained for: the word itself wasn't necessarily complicated, but one thing led to another, and what we've ended up with is a series of four posts that I've made pertaining to this single word.  The first post is a look what it means to be anadromous, as well as the opposite of anadromous, "catadromous."  During my investigation of these two terms, I came across the North American eel, a catadromous fish that is native to the Atlantic Ocean and is found in many rivers along the coast.  Curious to learn more about the life cycle of this eel, as well as its spawning grounds in the Sargasso Sea, I consulted Dr. Joe Richardson, a marine biologist that conducts ecology tours on Tybee Island in Georgia.  After going on one of these fantastic tours several years ago, I asked Dr. Joe about doing a guest post on the blog.  He was very kind to oblige, and HERE is a link to that post.  He was also kind enough to answer several of my questions regarding the eel, as well as the Sargasso Sea, and the second post focuses on my discussions with him.

A picture of Dr. Joe Richardson holding up a Portuguese Man of War on one of his awesome Tybee Beach Ecology Tours!  Photo Credit: mermaidcottages.com

I also wanted an example of an anadromous fish, and the classic example of one of these critters are many types of Pacific salmon.  To learn more about them, I consulted two fisherman who had come in to talk to my Outdoor Ed class last year.  They are both great people, really funny and very passionate about what they do.  I first talked with Wallace Westfeldt, the Head Guide at Front Range Anglers here in Boulder.  Wallace sent me several pictures and stories about fishing for salmon off the coast of Alaska, as well as in Idaho.  My interview with Mr. Westfeldt will be the third post, while the fourth post will be an interview with the second fisherman from my Outdoor Ed class, a man by the name of Larry Quilling, who also has had some interesting experiences fishing for Salmon in Alaska, as well as in Oregon.

Wallace Westfeldt holding a Steelhead salmon in Idaho.  By this point, these incredible fish have already swum 850 miles!  Photo Credit: Wallace Westfeldt 

Larry Quilling holding a spring Chinook salmon in the Trask River in Oregon.  Photo Credit: Larry Quilling.

I hope you all find this as interesting as I do!  Definitely glad to be back!

No I Did Not Mean Triceratops, I Meant Ceratops

Recently, the folks over at the Best Western Denver Southwest purchased yet another fossil cast for their amazing hotel!*  This time, the cast is of a skull nicknamed "Judith," a specimen that is referred by some paleontologists to the dinosaur genus Ceratops.  And, no, I didn't mean to say Triceratops.  Don't feel bad if you haven't heard of Ceratops montanus: as a matter of fact, I hadn't really heard of it either until several weeks ago, when Greg Tally informed me that the Morrison Natural History Museum would soon be receiving a very large box in the mail!  Judith is still in the Cretaceous Room here at the MNHM, where she will stay for at least a few more weeks.  I really didn't know much at all about this dinosaur, and was eager to learn more.  Unfortunately, there's not much out there, as Ceratops is based on just a few bones that were discovered in the late 1800s.  Despite the lack of material, Ceratops does have a pretty fascinating history, and is an incredibly important dinosaur; not because of what has been discovered about the fossils themselves, so much as what these fossils resulted in.

Greg Tally peers through one of the fenestrae (literally means "window" in Latin) in the skull of Judith, the Ceratops montanus skull for the hotel that is temporarily on display at the Morrison Museum.  Photo Credit: Greg and Meredith Tally

When it comes to giving an animal or a group of animals a scientific classification, there are a lot of hoops you have to jump through, and a bunch of rules you have to follow.  Sometimes, groups of animals are named after the best known and understood animal in that group.  For example, Stegosaurus is the genus of dinosaur that defined the group of animals called the stegosaurs, and Tyrannosaurus is the genus of dinosaur that defined the group of animals called the tyrannosaurs.  Sometimes, it isn't quite as simple.  Think about it this way: Las Vegas is easily the most famous city in Nevada, and I'm sure I'm not the only one who spent a significant portion of their childhood thinking that Las Vegas was the capital of Nevada.  However, it is Carson City that holds the official title of capital.  Even though Las Vegas receives much more attention than Carson City, the state of Nevada isn't simply going to change where its capital is, and to the best of my knowledge, a change like that never really happens.

Although that comparison was a bit of a stretch and had about as many holes as the skull of Chasmosaurus, I think you get my point.  The same thing goes for scientific names.  Although Triceratops is the best known individual of the dinosaurian group called the ceratopsians, this group is still called the ceratopsians, as opposed to being called the triceratopsians.  That's because it was Ceratops, and not Triceratops, that was described by scientists first.

Ceratops montanus, temporarily on display at the Morrison Natural History Museum.  Photo Credit: Greg and Meredith Tally

The year was 1888, and paleontology in western North America was still going strong.  We've talked about the Bone Wars between paleontologists Othniel Charles Marsh and Edward Drinker Cope before, and we are going to revisit Marsh in this post.  To maximize the number of fossils he could describe, Marsh called upon the talents of a large number of fossil collectors, including the always brilliant Arthur Lakes in Morrison, Colorado.  Another of these collectors was a man named John Bell Hatcher.  Although Hatcher should also be remembered for a large number of his contributions to paleontology, for our purposes here we remember Hatcher as the man who discovered Ceratops.  On a trip to a known dinosaur fossil site near the Judith River in Montana, Hatcher discovered a number of fossils.  One of these fossil discoveries was composed only of a pair of horn cores.

Doesn't sound like much, does it?  Well, truth be told, it wasn't, though it was enough for Marsh to realize that he had something new.  If you click HERE, you can view the two page paper that Marsh published in 1888 that briefly described this new discovery as an animal called "Ceratops montanus."  There are several things of interest that we should take away from this paper, some of which are:

1. Marsh originally suspected that this new creature was "nearly allied to Stegosaurus of the Jurassic, but differs especially in having had a pair of large horns on the upper part of the head."  Marsh got the location of the horns right, but the close relation to Stegosaurus.....not so much.  Given the enormously tiny sampling of bones he had to work with though, it's not a surprise that Marsh compared this new animal to something that he already knew a good deal about.  Keep in mind that this is the very first scientific description of a ceratopsian dinosaur, so Marsh just had to go off of what had already been discovered.  Which was nothing.
2. Marsh notes that the "position and direction" of the horns could be likened to the enormous Meiolania, an extinct turtle from Australia, as well as the lizards in the genus Phrynosomax, the horned lizards.  He also notes that amongst the dinosaurs, the "only known example of a similar structure....is the single median horn-core on the nasals of Ceratosaurus," a mid-sized theropod dinosaur from the Late Jurassic Morrison Formation.   
3. In 1887, the year before this paper was published, geologist Whitman Cross sent Marsh a pair of horn cores about two feet in length and six inches across at their widest point.  Discovered right smack dab in the middle of where Denver, Colorado is today, Cross relayed to Marsh that they had been discovered in beds of Cretaceous rock.  Marsh, however, decided that these horns must have belonged to some sort of enormous bison, and gave the horns the name "Bison alticornis."  Perhaps Marsh was still suffering from the misconception that the 1887 discovery was, indeed, an enormous extinct bison, as these 1887 Denver horn cores are not mentioned in the brief Ceratops paper.  It is mentioned, however, that if the horns were discovered "detached," their "resemblance in form and position of the posterior horn-cores to those of some of the ungulate mammals is very striking," and the horns would "naturally be referred to that group."  I have no evidence to support my hypothesis, but I wonder whether this comparison to the mammalian ungulates is insurance on the part of Marsh, as perhaps at this point he had recognized the true nature of the 1887 horn cores.  This is pure conjecture on my part, and is mostly irrelevant anyways, as in 1889 Marsh recognized the dinosaurian nature of the Denver cores, and referred them to the genus Ceratops.  Today, these horn cores are regarded as belonging to Triceratops.
4. Marsh mentions that several limb bones, vertebrae, and teeth were also found in the Ceratops horizon, as well as several bits of dermal armor, and states that he believes they also belonged to Ceratops.  Whether this is true or not I do not know, but what I do know to be false is Marsh's next sentence, in which he states that the bones "indicate a close affinity with Stegosaurus, which was probably the Jurassic ancestor of Ceratops."  The specimen is housed in the Smithsonian today, under the catalogue number USNM 2411.  A search through the online records of the Smithosonian shows that 2411 consists only of a partial skull, which seems to be consistent with what I've read in other sources.  I'm not sure whether these other skeletal elements mentioned above have found a definitive dinosaurian home, or whether their true owner is uncertain.  
5. The final paragraph is, in my opinion, inarguably the most important.  The paragraph reads as follows: "The remains at present referred to this genus, while resembling Stegosaurus in various important characters, appear to represent a distinct and highly specialized family, that may be called the Ceratopsidae."  In this paragraph, Marsh has created the group of dinosaurs that, more colloquially, we refer to as the ceratopsians.  Or, more colloquially than that, "those dinosaurs that look like Triceratops with those horns."

Ceratops was discovered in what scientists now call the Judith River Formation.  Several other ceratopsians have been discovered in this formation, and due to the small amount and fragmentary nature of the material that was originally described as Ceratops, most paleontologists consider the dinosaur to be a nomen dubium.  Nomen dubium pretty much means that the material is too fragmentary for it to be diagnostic, and can't really be used in the future to determine whether new specimens are the same as the original or not.  Whether or not the newly discovered Judith specimen currently on display at the Morrison Museum is, indeed, Ceratops is still up in the air, as the paper has not been published yet.  Almost all of my Ceratops knowledge is out on the table for all to see, so I am not going to speculate or attempt to draw conclusions about something that I don't really know enough about to have an informed opinion on.  Guess we will just have to wait and see!  In the meantime, come on by the Morrison Natural History Museum and the Best Western Denver Southwest to see Judith, and much more!

*If you've been living underground amongst worms and fossils for the last few months, you might not have heard of the hotel, so you can check out some incredible pictures of the best Best Western by clicking HERE and HERE.

Works Cited:

Did Velociraptor Hunt In Packs?

Ever since the movie Jurassic Park came out in 1993, people from all over the world added the name Velociraptor to their often-short list of dinosaurs they had heard of, joining more famous dinosaurs such as Tyrannosaurus, Stegosaurus, and Triceratops. While the dinosaurs portrayed in the movie have often been hailed as “ahead of the times,” Steven Spielberg of course had to make some assumptions about dinosaur behavior.

Michael Crichton, the author of the original Jurassic Park book, did too, which can be clearly seen when reading both of his Jurassic Park books. In the first one, a theory was circulating that Tyrannosaurus had eyes like a frog, that would be unable to see something so long as it didn’t move. This is reflected in the way Dr. Alan Grant, one of the protagonists in the novel (as well as the subsequent movie) tells his comrades to react when they are spotted by a Tyrannosaurus: just don’t move. (Don’t blink. Don’t even blink. Blink and you’re dead.)  

However, this theory was debunked by the time that it came for Crichton to write his next dinosaur-themed book, The Lost World, a sequel to Jurassic Park.  In the sequel, Ian Malcolm, who was also a protagonist in the first novel, moves to the forefront. He explains that the Tyrannosaurus from the first novel was probably just not hungry enough to attack them, and that it was just toying with them. A clever way of seamlessly working that scientific transition into the books without disrupting the canon of the story!*

Spielberg also played a lot of things up throughout the movies to make it more cinematic and exciting: and, to be honest, I can’t really blame him, at least not as critically as some paleontologists do. (That, however, is a story for another time). Today, however, we are going to be talking about one cinematic Spielbergian leap, and the resounding effect it has had on paleo-enthusiasts the world over: the idea of raptors hunting in packs.

In the books and movie, the Jurassic Park raptors are portrayed as clever, cool, and calculating killing machines with the intelligence of a dolphin or an ape. Scientists know, however, that while animals such as Velociraptor and Troödon may have been smarter than their mammalian counterparts of the time, their intelligence nowhere near reaches that of some modern day cetaceans and primates. Most people don’t want to accept that, though: they want their dinos really smart!

Here’s my stab at psychology for the day. In my semester long psychology course that I took last year, we discussed something in a relationship and everyday life called a fiction. Essentially, when human beings have feelings for someone, they develop what we call “fictions” in their mind. Fictions  about physical appearance, fictions about intelligence, and fictions about other redeeming qualities as well. If two people are projecting these fictions onto each other, then a relationship can develop. On the other hand, sometimes these people are confronted with these fictions, and they realize that they are not all that they are cracked up to be. When these people fall short of their fictions, some emotional turmoil can result. In my opinion, the reality of the Velociraptor, as well as the reality of the rest of the dromaeosaurs, falls short of people’s expectations. I think a similar thing is occurring right now with dinosaurs and feathers: people want their T-rex scaly, not feathery! That might be why many people seem so opposed to the idea.

“All right,” people say. “So Velociraptor wasn’t a genius. It still hunted in packs, though, right?” It seems like a fairly obvious answer: “Of course they did! ….Right? I mean….if you think about it….” It’s when you start to really think about the evidence that this idea really falls apart. First, let’s look at a related animal called Deinonychus. Deinonychus is a mid-sized dromaeosaur, about thirteen feet long, and weighing about as much as a wolf. Living during the Early Cretaceous Period, between about 118 – 110 MYA, remains of Deinonychus have been found in the western United States. Deinonychus remains aren’t always found solo, however: in some cases, it looks like Deinonychus might have dined and died! At several different sites, Deinonychus remains have been found buried in close proximity to a large herbivorous ornithopod called Tenontosaurus.  Shed teeth from multiple animals seems to indicate that these animals might have been feeding together. Some paleontologists take this a step further, and propose that, not only did these animals feed together, but they lived and hunted together, too!

In this post, I am going to be using several modern-day analogues to point out flaws in some theories. (We’ve already done it with the deer!)  This time, we’re flying over to Indonesia to visit the Komodo dragon. The Komodo dragon is a very interesting animal that, like many other animals, will resort to cannibalism. The young Komodos take to the trees, hiding up in branches to light to support the weight of the adults.  The Komodos lead a generally solitary existence: that is, until it comes time to feed. At feeding time, the dragons will swarm all over the carcass, each fighting for a stake of the meal. To an outsider, unaware of how the animal had been killed, it might be interpreted that perhaps this was a family group that worked together to bring down a much larger prey.

Another comparison I like to make is a theoretical one. Imagine that a pride of lions has subdued a zebra on the plains of Africa. After they have eaten their fill, they move off into the shade to sleep off their recently acquired weight. Immediately afterwards, the vultures swoop in on the kill. Suddenly, somehow a flash flood overtakes the carcass and the vultures, leaving them buried in mud, sand, and silt. Over the next few thousand years, their remains fossilize. One million years later, paleontologists come across this find. To their eyes, it would appear, for all intents and purposes, like the vultures ganged up in a pack to subdue this one-toed creature. Maybe not the best comparison, but one that I always like to think about.

So does the evidence seem to allow us the conclusion that multiple Deinonychus fed together? I would say yes, the evidence does support that conclusion. Does the evidence support the conclusion that multiple Deinonychus lived together, and worked together to bring down the Tenontosaurus? In my opinion, I don’t think that that is enough evidence. Other paleontologists disagree, however, leaving the matter open for debate. Right now, what we need is a good fossil trackway.

Pyg learns about several baby Apatosaurus tracks at the Morrison Natural History Museum.  Together, these tracks create a trackway, which has revealed some very interesting behavior about these young sauropods!  To learn more, make sure to check out the museum's Facebook page HERE!

We’ve talked about trackways on the blog before. Fossil trackways are also often good evidence for group moving. We have many trackways that show groups of dinosaurs, such as sauropods, moving together in multi-age herds. We’ve talked before about the exciting conclusions that paleontologists are drawing by studying blocks of fossil footprints at the Morrison Natural History Museum. While fossil footprints aren’t always necessarily the final say, they are simply one more piece of the puzzle. And when it comes to dromaeosaur footprints, footprints that many different paleontologists agree belong to a dromaeosaur, we have none. Zilch. Zero. Nada. No dromaeosaur footprints. Not yet, anyways. So there’s one possible line of evidence down the drain.

Pyg compares her foot to the smallest baby Stegosaurus footprints in the world, also at the Morrison Natural History Museum!  These footprints us gain insights into social behavior, animal size, and locomotion.

Thus far, it doesn't seem like we have any evidence in FAVOR of Velociraptor hunting in packs. But evidence can work both ways: what about evidence AGAINST Velociraptor as a pack hunter? As a matter of fact, there is one main line of evidence that I find to be, if not conclusive, highly indicative of the truth being the pack hunting. This line of evidence comes from the environment that Velociraptor would have lived in. Velociraptor inhabited what is now the Gobi Desert of Mongolia between around 70 and 75 million years ago, during the Late Cretaceous. Back then, the Gobi looked a lot like it does today: deserty. Now, this is very important. Think about desert animals today, specifically the carnivores, but the herbivores as well. Although the desert is certainly not a lifeless place, it is by no means a party like the African Serengeti, or the great plains of North America (before the railroads came through and people killed almost all of the bison). There simply isn't enough food for large animals to get by, especially not large groups of them.

Now think about a standard predator/prey ratio seen in environments today. Let's talk about my home-state of Colorado. There are lots of places to hike in Colorado, and in almost any part of the state you can see some sort of deer, be it mule deer, white-tailed deer, elk, or moose: you name it, you can probably see at least one of these cervids at almost any place in Colorado. Now, consider this: how often do you see bears in Colorado? Or mountain lions? Not terribly often, and especially not very often when you consider how often one sees deer. That's because of the predator/prey ratio. Essentially, if the balance between predator and prey is not kept in check, then populations will crash. Therefore, it is imperative that the prey species outnumber the predator species by what is usually a significant margin, otherwise the predators will overhunt, and they will starve to death. (For a more complete discussion of the predator/prey ration, this time in the context of the lynx/hare cycle of Canada, click HERE).

Some predators can get away with hunting in groups or packs because the prey species are relatively abundant. For example, the African Serengeti. The prey density is just so incredibly high that many different types of predators, such as lions, hyenas, and African wild dogs, can all hunt in packs. It works for them, because there are just so many prey species there!

Now let us bring our attentions back to the deserts. You can walk for miles, you can drive for even more, and see hardly a sign of any vertebrate life. Most likely, all you will see is a vulture or a hawk soaring the thermals high above you, watching for its next meal. If you're lucky, you might see a deer, or possibly even a javelina (a pig-like creature native to the south western United States, as well as Central and South America). You aren't going to see a lot of them, though. And if the prey isn't plentiful, then the predators sure aren't going to be, either!

Although dinosaurian-dominated ecosystems were undoubtedly different in some aspects from the mammalian-dominated ones of today, the fundamentals of the predator/prey ration would still stand true. There just wouldn't have been enough food to go around for these animals to have been pack hunters!

So, the final question: did Velociraptor hunt in packs? Or didn't it? If I had to hazard an answer, I would say no, no they did not. Due to the extreme lack of evidence in favor of this social behavior, as well as some evidence that seems to indicate that they wouldn't have, I would say that they did not hunt in packs. Obviously, with future discoveries, my ideas may change, which is one of the great things about science: we are always learning new things! And who knows: maybe one day, it will be one of YOU who discovers that crucial bit of evidence that shows that Velociraptor did, indeed hunt in packs!

OK, that was WAY too cheesy to leave like that. I felt uncomfortable even writing it. Let's end on a joke, instead. Why couldn't T-rex clap its hands? Huh? Give up? Because he was dead. Thank you ladies and gentlemen, I will be here all week.

A special thanks to Matthew Mossbrucker and Robert Bakker for their helpful information in making this post!

*To be honest, the whole concept of the theory doesn’t make a lot of sense: think about modern-day deer as an analogue for extinct prey species. If they see a predator, they are going to freeze, as it is much more difficult to pick out a still animal from the surrounding landscape than it would be a moving animal.  So predators would have to be able to pick out the prey, otherwise it would never capture one.  This freezing behavior on the part of deer when they are startled also explains why deer often freeze in front of car headlights: deer in the headlights!

The Dino Hotel Nears Completion! Part 2

As I mentioned IN THE LAST POST, the Best Western Denver Southwest is nearing its completion!  Soon, it will be the most powerful natural history hotel/museum in the entire galaxy!  In this post, we are going to see more of what makes this dinosaur hotel so freaking awesome!  Let's check out some of the skulls and bones that are going to go in the hotel!  First off, an awesome skull of an Acrocanthosaurus!

A bunch of other awesome bones for the hotel were delivered a few months ago to the Morrison Natural History Museum since the lobby at the hotel wasn't finished yet!  Any guesses as to what is inside of the crate?

I hate to say it, but your guesses were probably wrong.  Here is what was inside, with Pyg modeling for scale!  First off, a pair of Brachiosaurus femora!

A Pachycephalosaurus skull!

One day when the Pachycephalosaurus skull was at the museum, Dr. Bob came in one day with a few other pachycephalosaur skulls belonging to Stygimoloch and Dracorex, and had us paint them!  

You can see that all three skulls are approximately the same size: there's NO way that they are all the same animal, as some paleontologists believe!

Another great picture of the Pachycephalosaurus skull!

Here's another dinosaur skull, this one is Edmontosaurus!

And the third and final awesome skull, a Camarasaurus!

The hotel has many other cool specimens, such as this Allosaurus skull, which was in the lobby!

Not only are there some FANTASTIC skulls, the hotel has some casts of fossil skeletons, as well!  Here is the plan for Wadsworth the Stegosaurus, hanging above the front desk!

First, here is Good Sir Wadsworth before being brought inside!

Wadsworth being hung up!

And finally, the lobby, complete in all of its glory!  Notice the Brachiosaurus femora off to the left, and the Edmontosaurus skull in the cabinet around the middle of the picture!

Here are some more great pictures from the lobby!  Here are the curiosity cabinets under construction:

And the final product, with the Allosaurus skull above the fireplace!

If you travel to the dining hall, right off the lobby, you can enjoy lots of fun food, just as an enormous Tylosaurus (now named Sophie) would have done 70 million years ago!  First, some pictures of Sophie!

The flipper of the specimen!

As we mentioned before, this Tylosaurus wasn't hungry when it died!  In the stomach of this beatsie are the remains of a small creature called Dolichorhynchops!  To learn more about both Tylosaurus and Dolichorhynchops, click the link HERE!

Some days, you can also check out a fun-filled and exciting fossil table, crammed full of awesome goodies!  Here are several shots of that!

They also have an awesome donation box for the Morrison Museum!  This mosasaur skull, belonging to another Western Interior Seaway critter called Clidastes, will sit inside of it!

Indeed, this hotel is full of prehistoric from top to bottom!  Actually, literally to the top, as the hotel will have a Pteranodon weathervane!  Here are the plans, and the actual weathervane itself!

Want to hear more about the hotel, but just won't be in the area anytime soon?  Not a problem!  Like their Facebook page by clicking HERE!  Not only do they share lots of awesome pictures and fun facts, they also create lots of fun Dino Memes!  Here is one of my favorites (partly because they included a link to our Xiphactinus: The Inception Fossil post when they uploaded the picture to Facebook!), but partly because it's an awesome meme!

And here is the first in a series of "Fun Fact" memes that I am working on with the Tally's!

Hope to see you all at the hotel!

Other Things at the Quarry: Dinosaur Road Trip With Grace Part 5

PREVIOUSLY, ON BATTLESTAR GALACTICA:

-Grace Albers and I are taking a trip down to Dinosaur National Monument in Utah and Colorado.
-We checked out some cool petroglyphs and then camped the night.
-We arrived at the quarry and checked out all of the awesome bones on the quarry face.
-And now....

In the last post, we looked at a bunch of pictures that we took from the second floor viewing platform of the quarry face.  In this post, we have traveled below the viewing platform to the first floor to check out some of the awesome fossils that they had below!  Below is a diagram of the quarry wall that shows where the original discovery of the site was made!

Here we have the skull of a species of Allosaurus called Allosaurus jimmadseni!  I believe that this species has not been officially described, but to be honest, the genus Allosaurus is a bit of a mess, so I'm not really sure what exactly is going on!

The arm of Allosaurus.

The foot bones that were discovered of Allosaurus jimmadseni inside a reconstructed footprint!

The skull of Allosaurus jimmadseni in situ (which means that it still is in the rock).

The skull of Allosaurus!

The reconstructed skeleton of Allosaurus!

This nearly complete juvenile skeleton of Camarasaurus is apparently the most complete sauropod skeleton ever found!

One of the signs at the quarry said that a new species of sauropod, called Abydosaurus, has been discovered in the monument in a different geologic formation called the Cedar Mountain Formation!

Here is the skull of Apatosaurus louisae.

A Camarasaurus tooth on the left and several Diplodocus teeth on the right!

Skin impressions of another sauropod dinosaur called Barosaurus!

One of the tail spikes of Stegosaurus!

One of the plates of Stegosaurus!

Some of the baby Stegosaurus bones discovered in the quarry!

The skull of the small ornithopod Dryosaurus!

Unidentified lizard legs and feet.

A small crocodilian called Hoplosuchus.

A fossil conifer cone.

A fossil conifer branch with shoots!

The fossilized remains of an extinct salamander called Iridotriton!

The fossilized remains of the extinct frog Rhadinosteus!

A fossilized shell belonging to a juvenile Glyptops, a type of turtle!

A lungfish tooth plate from a fish called Ceratodus!

The shell of another extinct turtle called Dinochelys.

A fossil clam.

The fossilized belly scales of the extinct crocodilian Goniopholis.

The fossilized jaw bone of the same extinct crocodile, Goniopholis!

Next time: a few more petroglyphs and the Harper's Corner Drive!

The Quarry: Dinosaur Road Trip With Grace Part 4

PREVIOUSLY, ON BATTLESTAR GALACTICA:

-Grace Albers and I are taking a trip down to Dinosaur National Monument in Utah and Colorado.
-We checked out some cool petroglyphs and then camped the night.
-We arrived at the quarry.
-And now....

Before we begin, I am going to upload two pictures of dinosaur skeletons that may be useful throughout this post.  The first is the sauropod dinosaur Camarasaurus, and the second is the stegosaur Stegosaurus.  When you see the labeled bones of two other sauropods called Diplodocus and Apatosaurus, you can refer to the Camarasaurus skeleton diagram below.  

A sidelong shot of the quarry face!

Pyg takes a look at the quarry face!

The vast jumble of bones from all sorts of different animals and dinosaurs is thought to be the result of the death of various animals upstream, and then their bones being washed together!  This explains why most of the bones at the quarry are disarticulated (or not fossilized next to each other like they would look like in real life), and are miscellaneous bones from such a wide assortment of creatures!

Bones aren't the only things that are found at the quarry, however!  Here are two pictures of fossil wood!

Pyg takes another look at the quarry face!  You can see the first fossilized log right above her head in the picture.

Remember before, when we mentioned most bones at the quarry are disarticulated?  Well, there are some bones that are articulated, most of which are part of the vertebral columns of various animals.  This looks like the tail vertebrae of something!

An articulated leg, possibly of a Stegosaurus.

A pair of femora belonging to something!

Looks like a rib bone to me!

An assortment of more bones.

Most of what would be considered the "cool fossils" (like skulls and claws) have been removed from the quarry.  According to Dinosaur National Monuments website, the only two skulls that remain belong to Camarasaurus: here is one of those skulls!

I can't identify most of the bones that I see in these pictures, but fortunately the monument sells a guide for a dollar which we bought.  Although the guide doesn't have all of the bones in it (not by a long shot!), it did have a fairly wide selection.  Here are a few of the bones that they identified!

One of the only claws that I saw (not to say that there weren't any others out there) is in the picture below.

Possibly a sauropod ilium.

Several bones identified.

What looks to me like a sauropod vertebrae.

Several articulated vertebrae.

More bony jumbles!

You can also see the top of the quarry wall in this bony jumble shot!

A Stegosaurus plate lies just about in the middle of this shot!

Here is a brief guide to some of the Camarasaurus bones found in the quarry!

A Stegosaurus sacrum (the center, or "body," of the big butterfly-shaped bone) and the left and right ilium (the outer parts, or "wings," of the big butterfly-shaped bone).

More of the quarry face.

A few more shots of various articulated vertebral columns!

A close up of another vertebrae, possibly a sauropod!

A few more shots of Stegosaurus plates!

The plate from the last picture is in the top right hand corner of this picture of what I think might be a sauropod coracoid.

Next time: other things at the quarry!