Jurassic World: Facultative Bipedalism

In the new Jurassic World movie, the main movie monster is a critter that the movie characters called Indominus rex.  The dinosaur is a big guy, and its forearms are especially large, especially when compared to the tiny arms of Tyrannosaurus rex.  There were a few funky things going on with the Jurassic World dinosaur hands, but we can talk about that in a later post.  Today, we are going to talk about an interesting type of behavior exhibited by Indominus: facultative bipedalism.

Two baby Stegosaurus models on display at the Morrison Natural History Museum.  Stegosaurus individuals of all sizes would have been able to switch between walking on two and four legs, facultative bipedalism, which is the topic of this post.

Facultative bipedalism is an animal that can walk on both two or four legs, at least for a little bit.  For example, the gerenuk (Litocranius walleri), a type of African antelope, can rear up on their hind legs to nab plants off of some higher branches.  But they can't really walk on their hind legs, so they wouldn't really be considered facultative bipeds.  My little Djungarian hamster (Phodopus sungorus) will lean back on his hind limbs to manipulate food with his forepaws, as do many other types of rodents.  Meerkats (Suricata suricatta) often sit on their hind legs to observe their surroundings.  The extinct giant ground sloths would have reclined on their haunches to browse from the higher branches of trees.  But none of them would have moved around on their hind limbs, and therefore would not be classified as bipeds, facultative or otherwise.

Several gerenuk at Walt Disney World in Florida using their hind legs to eat some food off of the higher branches.  Photo Credit: Julie Neher

A little golden-mantled ground squirrel (Callospermophilus lateralis) using its forepaws to manipulate its meal at the Cheyenne Mountain Zoo in Colorado Springs.  Forepaw manipulation is something that many rodents can do. 

Another rodent manipulating an object with its forepaws. This North American porcupine (Erethizon dorsatum), also at the Cheyenne Mountain Zoo, is holding a primitive slingshot weapon.  Zookeepers have had a very difficult time controlling these animals.

A meerkat at the Cheyenne Mountain Zoo, using part of its termite mound as a lookout area.  It'll stand on its hind legs, but runs around on all fours. 

A Jefferson's ground sloth (Megalonyx jeffersoni) exaggerates the size of the fish it caught last summer at the Rocky Mountain Dinosaur Resource Center (RMDRC) in Woodland Park, Colorado.  Just like the gerenuk, the ground sloths would have reared up on their hind legs to consume vegetation off of a higher level.

A Glossotherium skeleton on display at the American Museum of Natural History in New York, walking quadrupedally.

The duck-billed hadrosaur dinosaurs and the iguanodonts are good examples of facultative bipeds.  They would have been capable of moving around on both two or four legs, depending on whether they were grazing lazily (quadrupedal) or moving more quickly (bipedal).

An Anatotitan skeleton on display at the American Museum of Natural History in New York.  You can see this skeleton is moving around on all fours....

....but the animal could also walk bipedally.

Stegosaurus was initially thought to be bipedal, and although most modern reconstructions show the armored dinosaur as a quadruped, fossil trackways at the Morrison Natural History Museum (MNHM) in Colorado demonstrate quite clearly that the baby Stegosaurus, tiny little six pound hatchlings, were entirely capable of moving around on their back legs!

Baby Stegosaurus model on display at the Morrison Natural History Museum, right next to the very first baby Stegosaurus track ever discovered by museum director Matthew Mossbrucker in 2007.

For stegosaur and hadrosaur dinosaurs, most of their weight was centered over their hips, and the same is true of some of the long-necked dinosaurs, such as Apatosaurus and Brontosaurus.  Fossil trackways of baby Apatosaurus at the MNHM show that the babies could run around on their hind legs, to keep up with their parents, and probably keep out of their way as well!  The little baby Apatosaurus tracks at the MNHM show the animal scooting along on its back legs, sort of like the modern basilisk lizard from South America.

Two trackways made by infant apatosaur dinosaurs, on display at the Morrison Natural History Museum.  The lower trackway has tracks from both the front and back feet, while the upper trackway has only hind foot tracks, and are spaced two to three times further apart than the ones in the lower trackway.  This shows that these baby dinosaurs would have been capable of running around on their hind legs!

Very few mammals are facultative bipeds, or even bipeds at all, with exceptions such as pangolins, jerboas, and kangaroo rats, as well as the regular old kangaroos.  Apparently, even cockroaches in the genus Periplaneta can run on their hind legs as well, if they get going fast enough!

A Parma wallaby at the Cheyenne Mountain Zoo, moving around on its hind limbs.

Here, you can see the same Parma wallaby, moving on all four legs.

A mounted skeleton of the Pleistocene kangaroo Simosthenurus at the American Museum of Natural History in New York.  As you can see, even though it looks like its twerking, it is on its hind legs, grabbing some vegetation.

Although Indominus was never shown really running on all four legs, and most of the time seemed like a biped, there were a few times where the beast would drop down to all four legs.  At those times, Indominus looked a bit like some of the earliest dinosaurs might have, as well as their close cousins.  Poposaurus and Postosuchus are both dinosaur cousins for whom the possibility of facultative bipedalism, or just regular bipedalism, has been suggested in the past.  Even if those specific critters weren't facultative bipeds, there were definitely cousins of theirs that were.


Works Cited:

Alexander, R. (n.d.). Bipedal animals, and their differences from humans. J Anatomy Journal of Anatomy, 321-330.

Weinbaum, J. (2013). Postcranial skeleton of Postosuchus kirkpatricki (Archosauria: Paracrocodylomorpha), from the Upper Triassic of the United States. Geological Society, London, Special Publications, 525-553.

Jurassic World: Shed Teeth

At one point in the new Jurassic World movie, the main character Owen Grady (played by popular actor Andy Dwyer) pulls a broken tooth from the main monster Indominus rex from the shell of one of the Gyrospheres.  Believe it or not, broken teeth just like this are incredibly important for paleontologists when it comes to studying many different aspects of dinosaur habits and behavior!  First, let's take a quick look at the anatomy of a dinosaur tooth.

A pair of Tyranosaurus rex tooth casts with my camera lens for scale.

In the picture above, both teeth belong to the famed tyrant lizard king Robert California Tyrannosaurus rex itself!  The tooth on the top is larger, but it wouldn't have appeared that much larger in the mouth of the animal.  The reason behind that is the darker brown part on the left of the tooth is actually the root of the tooth, and would have been inside the animals skull.  The tooth underneath, the darker brown one, is a shed tooth crown.  Dinosaurs, unlike mammals, have an infinite supply of teeth, and if they lost a tooth it simply didn't matter!  They would grow another one in its place in a few weeks.

Stan, the Tyrannosaurus rex skull on display at the Morrison Natural History Museum.  Look on the upper jaw.  See the largest tooth, just about in the middle of the tooth row?  Let's zoom in and take an inside look! 

This is a view from the inside of the Tyrannosaurus skull from above, a view that the lawyer from Jurassic Park probably didn't find quite as fascinating.  See the largest tooth in the middle of the picture?  Notice how there's another little bump at the top of the tooth row, where the teeth are emerging from the maxilla bone.  That's actually another tooth growing in underneath!  If we CT scanned the original fossil, you'd be able to see all sorts of teeth growing in underneath!

Here we have a dental battery of the famous Triceratops, on display at the Rocky Mountain Dinosaur Resource Center (RMDRC) in Woodland Park, Colorado.  Now take a look at the picture below. 

Here, we have an individual tooth of Triceratops, out of the dental battery that you can see in the picture above.  This specimen is from the Hell Creek Formation of South Dakota, and also on display at the RMDRC.

The reconstructed jaws of the enormous, sixty foot long shark Megalodon, on display at the Mace Brown Museum of Natural History at the College of Charleston in South Carolina.  Like other sharks, as well as dinosaurs, you can see the several rows of teeth in the jaws of this guy, as well as the enormous biceps on the arms of the sexy Chris Pratt look-alike on the right.  Biceps for scale are approximately 36 inches in diameter.

Here and below, we have pictures of part of the dentary of the large carnivorous theropod dinosaur Torvosaurus from the Late Jurassic Morrison Formation.  You can see on the end in the picture above, the tooth is growing in, while the rest of the teeth are pretty well established.  This fossil is on display at the University of Colorado Museum of Natural History in Boulder. 

Another shot of that Torvosaurus dentary seen above, you can see another tooth growing in as well, second from the left.

Shed teeth can be quite important for paleontologists when it comes to determining behavior of these extinct creatures.  When paleontologists discover shed teeth of an animal, it can be a good indicator that the dinosaur was feeding on something nearby.  Unfortunately, shed teeth are easily recognized as fossils by most laymen, and are therefore often picked up by the public or fossil collectors looking to make a quick buck, thereby destroying any information we could potentially gain from such knowledge.  With good samples of shed teeth, like those employed by paleontologist Dr. Robert Bakker at the Late Jurassic Morrison Formation site of Como Bluff in Wyoming, scientists can learn about dinosaur diets, habits, habitats, and behavior, such as group movement, pack hunting, and even whether dinosaurs cared for their young!

A shed tooth crown of a Tyrannosaurus on display at the RMDRC.

Several shed phytosaur teeth on display at the Denver Museum of Nature and Science.  Phytosaurs were distant cousins of dinosaurs, and looked a lot like crocodilians.

A shed tooth of Nanotyrannus, a small cousin of Tyrannosaurus rex, from South Dakota.

Leidyosuchus, a type of Cretaceous crocodilian, with several shed teeth.

Brachychampsa, another Cretaceous crocodilian.

In 1877, local geologist Arthur Lakes discovered the very first bones of the dinosaurs Stegosaurus armatus and Apatosaurus ajax in Morrison, Colorado, and if you check out the Morrison Natural History Museum, you can actually see them there today!  Surrounding the genoholotype of Apatosaurus ajax, the very first specimen called YPM 1860, was reported by Lakes to have seven shed teeth belonging to an allosaur surrounding the specimen.  This indicates some that the predatory allosaurs were actually feeding on the Apatosaurus, which is very interesting information for paleontologists to have!  Below are two pictures of part of that YPM 1860 specimen, with the Director and Chief Curator of the Morrison Natural History Museum Matthew Mossbrucker pointing to the shed allosaur tooth crown.  These pictures are from the collections of the Yale Peabody Museum in Connecticut.

Shed allosaur tooth crown in the matrix of YPM 1860.  Photo Credit: Matthew Mossbrucker 

Shed allosaur tooth crown in the matrix of YPM 1860.  Photo Credit: Matthew Mossbrucker

Non mammals rarely have more than one type of tooth in their mouth, and when they do, it can often be the cause of celebration.  For example, in our previous post about the Latin and Greek root of two, we discussed two animals called Dimetrodon and Dimorphodon.  Dimetrodon is an early ancestor of modern mammals, and its name means "two measures of teeth," as it has two different types of teeth in its mouth.  Dimorphodon is a type of pterosaur (sometimes referred to as pterodactyls), a distant cousin of Pteranodon, whose name means "two morphs of teeth," again in reference to the fact that two types of teeth are in the animals mouth.  The animal below is a dinosaur called Heterodontosaurus, who belongs to the eponymously named family of dinosaurs, the Heterodontosauridae.  As you can see in the picture below, Heterodontosaurus has several larger teeth in the front of their mouth, and smaller teeth in the back.

Heterodontosaurus, a small little Early Jurassic dinosaur from South Africa.  As you can see, there are two different types of teeth in their mouth, larger ones in the front and smaller ones in the back.

One of the things that make mammals special is our teeth.  One of the most classic features of us mammals is our varied teeth.  In us humans, we have our incisors and canines in front, and our chewing molars in the back.  Since most mammals were only about the size of a shrew back during the Mesozoic Era, the time of the dinosaurs, in many places such as Como Bluff in Wyoming, paleontologists rely almost exclusively on the teeth of the tiny little mammals, since the teeth are much harder and more durable than the rest of the skeleton.  Below, we have a trio of elephantid molars on display at the Mace Brown Museum of Natural History at the College of Charleston in South Carolina.  Look at how varied the teeth are!  The first two belong to animals whose teeth were better adapted for crushing and grinding tougher vegetation, while the last molar would have been better for mashing up grasses.

Cuvieronius tropicus, a Pliocene-aged elephantid from South Carolina.  Large, high-cusped molars for crushing and grinding tougher vegetation.

Stegomastodon mirificus, a Pliocene and Pleistocene-aged elephantid, discovered in the Ashepoo River of South Carolina.  Like Cuvieronius, Stegomastodon also has those large, high-cusped molars that are great for demolishing tough plant matter.

The Imperial mammoth (Mammuthus imperator) from the Pleistocene of Florida.  These guys have a similar design of tooth to the dental battery of the ceratopsian dinosaurs mentioned above.  The duck-billed dinosaurs, or hadrosaurs, also had a similar design.  These teeth are broad and flat and good for mashing up grasses.

Shed teeth can be pretty important when paleontologists study fossils and extinct animals.  They are good at establishing behavior, and can be pretty important for long-term studies of paleoenvironments.  So when Owen uses the shed Indominus tooth in Jurassic World, believe it or not, that's actually something that paleontologists do from time to time!

Jurassic World Premiere at the Alamo Drafthouse

Currently, the crews of the Morrison Natural History Museum and the Best Western Denver Southwest are manning a large booth in the lobby of the Alamo Drafthouse of Littleton, Colorado, taking part of the hype that has accompanied the release of the new Jurassic World movie.  People have been clawing to get in and see the movie, and are pretty excited to see some awesome fossils and fossil casts right there in the lobby!

The Acrocanthosaurus arm clawing its way towards the Alamo Drafthouse building.

We brought over several of the awesome casts that are (usually) on display in the lobby of the Best Western Denver Southwest Dino Hotel, including a Uintatherium skull, one of the Brachiosaurus femora, a Camarasaurus skull, and the prize of the exhibition, the Acrocanthosaurus skull and arm!

Fran, the most complete skull of Acrocanthosaurus ever discovered.  A giant cousin of Allosaurus, this skull was discovered in Oklahoma, and would have lived during the Early Cretaceous Period, around 110 million years ago.  The dinosaur was first described in 1950 by paleontologists J. Willis Stovall and Wann Langston Jr.

A skull of the long-necked sauropod dinosaur Camarasaurus, statistically the most common dinosaur discovered in the Late Jurassic Morrison Formation.  This Camarasaurus specimen, nicknamed "E.T.," was discovered at the Howe Stephens Quarry in Wyoming.  Check out his page on the Black Hills Institute Website by clicking HERE.

A Tyrannosaurus rex arm picks the nose of the Acrocanthosaurus.  Now that's something you don't see every day.

Matt Mossbrucker, the entire Tally family clan, Justin Sewell from TheOneRing.net, and myself have been here since Thursday, talking with folks before and after their movie experience.  Part of what makes the Alamo Drafthouse experience particularly interesting is they do a half hour preshow, where they pull awesome old footage and fun videos that relate to the feature presentation, so you get to enjoy a half hour of awesome old dinosaur footage as well!  So definitely come on by and say hello, and enjoy the movie while you're here!

From left to right: Joe Tally, Greg Tally, and Caroline Tally doing very important science.

Matthew Mossbrucker, Director and Chief Curator of the Morrison Natural History Museum, poses next to the gigantic femur of the Brachiosaurus, with the Acrocanthosaurus skull slung over one shoulder and the Camarasaurus skull in the other.  Imagine how cool you would look carrying that Brachiosaurus femur around in a hotel parking lot. 

Merlin Barnes, Outreach Specialist at Dinosaur Ridge, our neighbors both at the Drafthouse and in real life.

I got to watch Jurassic World this afternoon, and I was very pleased with the movie, I thought it was very entertaining and a great movie overall!  For the next few days, I'm going to spend as much time as I can talking about different aspects of the movie, both accurate and inaccurate aspects of it, for all of your reading and viewing pleasure!  Some topics I plan to talk about include:

• Pterygoid teeth
• Shed teeth
• Feathers
• Faculative bipedalism
• Herding and group behavior
• Defensive tails
• Head butting
• Dinosaur hands and rabbit paws
• Venomous and poisonous dinosaurs
• Threat displays
• Paleo art
• Opposable thumbs
• Pterosaur diets
• Dinos in the snow
• Maybe even a little cuttlefish talk too

I had a lot of fun watching the movie, and I'm still having fun talking with the crowds of people entering and exiting the theater, hyped up and excited to learn more about dinosaurs and their prehistoric contemporaries!  I'm also looking forward to using the movie as an opportunity to engage people about dinosaurs, and hopefully you who are still reading this post will, too.

Matthew Mossbrucker (left) and Greg Tally, co-owner of the Best Western Denver Southwest Dino Hotel, walk the Brachiosaurus femur out of the lobby of the hotel, on its way to the Alamo Drafthouse.  We thought it could use a nice explosion in the background, so....

....this was born.

Night Changes: Why Color Blind People Aren't So Strange (But Really Are at the Same Time)

"Why does your Tyrannosaurus skull have rings on its eyes?"  "Why are reptiles and amphibians, animals often brushed aside as "less superior" to mammals, frequently very colorful?"  "By contrast, why are so many mammals so drab?"  "Does it ever drive you crazy just how fast the night changes?"  All of these questions and more are ones that I've either received or asked over the last few months, and surprisingly, they are all (sort of) tied together.

A selection of the stars of this post.  In the top row from left to right, we have a Prestosuchus skull, Micronesian kingfisher, Opthalmosaurus skull, African elephant, and a white-necked raven.  Second row, we have a male peafowl, Microraptor specimen, myself pulling a "District 9" with a T-rex arm and Stan the T-rex next to me at the Morrison Natural History Museum (now you finally know what I look like [irresistible], you can cross that off your bucket list), a Mandarin Goby, and the hand of Zach Evens descending upon a brightly colored newt.  Finally, in the bottom row, we see a pair of tiger salamanders, a coyote that ran amok on the University of Colorado campus last winter, and several bees swarming a hummingbird feeder at the MNHM.  Did I forget anything?  Oh, right, the album cover of One Direction's new album "Four."  A further bonus for all you "Natural Worlders" out there: can you find the names of twenty-one One Direction songs scattered throughout the blog post?  Try not to stay up all night searching for them, one way or another I have no doubt you can figure it out.  Just shoot me and email, and I can get back for to you about where they are.  Just one of those little things that makes reading my blog so worthwhile.

When people first walk into the Morrison Natural History Museum near Denver, Colorado, you might see a rock hammer-toting, cowboy-hat wearing, beard-wielding paleontologist talking about lizard pseudo-placentas, the anatomy of the dinos in Jurassic park, or whether said dinosaurs would taste like chicken.*  You might notice the bathroom first, which is more or less right across the room from the front entrance.  Or, like most people, you might notice our cast of Stan, one of the most complete specimens of Tyrannosaurus rex known to mankind.  We tend to get a lot of questions about this bad boy (T-rex consistently being the favorite dinosaur of pretty much everybody), and one question that we get a lot pertains to his eyes.  You might have missed it if you were looking at the fantastic picture above, but take a look at the pictures below and you should see it: it looks like we've put little rings where the eyes should be.  The question is: Why does our Tyrannosaurus skull have rings on its eyes?

Believe it or not, this was not a once in a lifetime phenomena, and it is not a trick (excuse me, an illusion) we created to make the placement of the oculars more apparent for the casual observer.  It's real, and it's called the sclerotic ring.  Without getting too technical, the sclerotic ring is a ring of several bones that actually is inside of the eye of the animal, and is usually thought to help support the eye.  What I find really interesting about the ring is that the default condition in vertebrate animals is possession of this bony ring.  Even though you might not see it in a lot of museum specimens due to display difficulties or preservation issues, a sclerotic ring is present in most/all fish, lizards, birds, and dinosaurs.**  You won't see it in modern crocodilians, though, and it seems like at least some snakes don't have them either.  What's another group that doesn't have the ring?  You guessed it: mammals.

One with the ring, one without.  My bro Masaki Kleinkopf poses next to the mounted skeleton of the pterosaur Pteranodon at the Rocky Mountain Dinosaur Resource Center (RMDRC) in Woodland Park, Colorado.  Check out dat ring doe.

A mounted skeleton of the emperor penguin (Aptenodytes forsteri) at the American Museum of Natural History (AMNH) in New York. If you liked it, you should have put a ring on it. 

Skull of the therizinosaur dinosaur Falcarius on display at the Wyoming Dinosaur Center in Wyoming.  One ring to rule them all.

At this point you might be expecting some profound, fascinating statement that explains why some animals have the ring and some animals don't.  Believe me, very few things would please me more than to be able to explain this to you.  Unfortunately, I don't know.  Even more unfortunately, nobody really knows!  Although various explanations have been put forth over the years, I can't really find a fool('s gold fire)proof, satisfactory interpretation that broadly explains this phenomenon, and in this post I don't really wish to wade any further into this debate than we have already.  We have a few more questions to answer tonight.

The small feathered dinosaur Microraptor on display at the Wyoming Dinosaur Center in Wyoming.  You can see both the impressions of feathers off the wings and legs (making this Velociraptor-cousin comparable to the Sopwith Camel British biplane active during World War I), as well as the sclerotic ring nestled within the orbital.  My preciousssss.....

The name of this ichthyosaur, Opthalmosaurus, actually means "eye lizard," the name of which refers to the big @$$ eyes and sclerotic rings of this particular genus.  Better not put it on your finger, Dumbledore, it might be a Horcrux.

The pseudosuchian Prestosuchus, on display at the AMNH in New York.  This ring just exudes fellowship, don't you think?

Why is Nagini usually more brightly colored than Crookshanks or Scabbers?  Why are Polly's pigments predominantly prettier than Pongo's or Perdita's?  Although undeniably more handsome after true love's first kiss, there's no denying than many frogs and toads out there are much more exciting to look at than Prince Charming.  There's got to be a reason why the characters in "Finding Nemo" were so much brighter (sorry Dory, but I mean in terms of color) than Remy from "Ratatouille," or why Kevin is much more conspicuous than Dug in "Up." But what is the reason?  The answer seems to be fairly simple: with few exceptions, most mammals are colorblind. Primates are one of these exceptions, which is why we humans are able to differentiate between cherry and grape Jolly Ranchers and an elephant might fail, and why the Green lantern comic books and Bionicles absolutely tanked in the feline and canine demographics.  Mammals are good at a lot of things, but one thing that they're not very good at is seeing in color.  A picture is better than words in many cases, so check out some pics below of animals that can most definitely see in color.

Here we have a white-necked raven (Corvus albicollis) correctly putting four different colored game pieces into the correct slots at a special Teen Career Day event at the Denver Zoo that I attended with my sister. He did all eight tiles in the correct category, and it didn't take him very long, either! Some of my friends wouldn't be able to do it with such speed and accuracy....

Male peafowl (Pavo cristatus), often referred to as peacocks, are just one of many species of bird that use brightly colored feather to attract their mate.  Maybe that's why Sauron was so angry: he knew that, no matter what he did, the giant eagles would always be able to naturally two-up him.

A Micronesian kingfisher (Todiramphus cinnamominus) sittin' purty at the Denver Zoo.  Return of the King(fisher), am I right?

A clown fish (subfamily: Amphiprioninae) taking refuge amongst the stinging tentacles of a sea anemone at the Denver Zoo. 

The Mandarin goby (Synchiropus splendidus), a particularly beautiful fish, and very brightly colored as well. 

One of my two betta fish (Betta splendens), Juan Priestly.  Bright bodies with frilly fins?  Glad I'm not a betta fish, this one would steal my girl right out from under me.

Just like the default condition for vertebrates is to possess a sclerotic ring, so too does it seem that the default condition for vision is color.  So if mammals are supposedly so superior, why do so many of us lack this colorful condition?  Many paleontologists have been looking back to the Mesozoic Era, the age of the dinosaurs, to try and solve this colorful conundrum.  Just as mammals have been the dominant terrestrial vertebrates for the last 65 million years, so too did the dinosaurs rule the land during the Mesozoic, suppressing all other forms of life and filling most of the major terrestrial niches.  One of those life forms that was consistently suppressed from the Triassic through the Cretaceous was mammals.  Mostly small, shrew-like animals, Mesozoic mammals are usually thought to have been small, nocturnal creatures, pittering and pattering around the bodies of the sleeping dinos, ready to run at a moments notice.  Key word in that last sentence: nocturnal.

Can you see the little mouse-looking animal hiding underneath the box in the middle of the photograph?  That's Hufflepuff (Huffle to his friends), a small meadow vole (Microtus pennsylvanicus) that tried to hide underneath my legs when a red fox (Vulpes vulpes) happily tried to make a meal out of him last year on CU campus!  Knowing he probably had had the vole equivalent of a heart attack and taking pity on him, I said "I'll save you tonight!" and let him recover for a few days in my room before letting him go to let him live while he was young (which isn't long, I don't think most voles live longer than a year or so, but I could be wrong).  A nocturnal critter, he would have very little use for color vision, and has relatively drab coloration.

More wildlife from CU campus!  This coyote (Canis latrans) caused a bit of a stir last winter when it decided to crash on Farrand Field for a few hours, right in the middle of CU campus.  Although not exclusively nocturnal, coyotes are often active at night, but are quite adaptable, as was evidenced by this particular coyote's behavior, alive and well in the middle of campus!  Note the relatively drab coloration.

I have a friend who is partially colorblind, about as colorblind as an elephant according to some recent studies.  If you see him outside, he's going to be wearing sunglasses (unless he's done something to piss off Poseidon).***  Is he doing it just to look cool?  Well, yes, I suppose that's at least partially the case.  But for him, and for many other people who suffer from color blindness, it seems like they make up for it with above average night vision.  Essentially, an imbalance of rods (a photoreceptor that is not sensitive to color but is sensitive to light and dark conditions and aids in night vision) and cones (a photoreceptor that is sensitive to color and less sensitive to light/dark conditions) leads to many who are color blind reporting better than average ability to see what's going on in low-lighting conditions.

An African elephant drinking some water at the Cheyenne Mountain Zoo in Colorado Springs.  Drab colors?  You betcha!

When all of these seemingly disparate ideas are regarded holistically, it seems to make sense.  By default, most vertebrates enjoy a wide range of color vision (sometimes even a wider range than humans!).  However, during the Mesozoic dinosaurian domination, some groups of vertebrates such as the mammals were forced to take up residence during the night.  For millions of years, these little creatures lived a nocturnal existence, and it seems like being able to see in color no longer proved to be a competitive advantage for them.  Following the extinction of the dinosaurs and the subsequent radiation of mammals, it appears that the possession of color vision was unnecessary for them to survive and thrive.  Many mammals are still largely nocturnal today (think of your kitty at home and all of her midnight memories), which might have something to do with this disparity between their rods and cones.  All in all, it would appear that changes of the night can have some pretty profound effects on your ability to see across the color spectrum.


*You will probably come across them doing some serious work as well, but dinosaur taste-testing can be pretty important.
**I thought that Dr. Bakker, who I talked to a lot about this, mentioned that most or all frogs had the sclerotic ring, but I have been unable to confirm or deny this with a quick search through the resources I have at my disposal.
***Twice.

Works Cited: