If you are ever in London, the Natural History Museum (NHM) is a must see attraction. It ranks among the top natural history museums around. Schedule more than one day to see all the exhibits if you can, including their popular dinosaur exhibit that always draws large crowds. Many people have complained about the poor lighting and limited viewing space in that particular exhibit, but even with that, it is not to be missed. Accompanying the dinosaurs in the museum is an extensive online collection of fossil information, covering a wide range of dinosaurs. So given this, it should not surprise anyone that the NHM has put out a dinosaur book. The first edition of the book came out in 1993, with three more editions published since then, the latest one in 2006. We know a lot more about dinosaurs now than we did even ten years ago though, so how well does it hold up? Pretty well, for the most part, although a few Americans might be a bit perplexed by the British spelling that is occasionally different from American English. The NHM has a nice website on dinosaurs, which serves as a nice supplement to the book.
It is a long review, so if you want to skip to the summary conclusions, click here.
The Natural History Museum Book of Dinosaurs
Publication Date: 2006. 144 pg.
Carlton Books. ISBN: 1-84442-183-X, 978-1-84442-183-1
AR Book Level: Not listed
Recommended for 10-14 year olds
Angela Milner has been a well respected paleontologist for decades and has been the leading researcher for dinosaurs at the NHM since the eighties, so if anyone is going to write a book about dinosaurs for the museum, it’s Dr. Milner. Tim Gardom is primarily known for this book, but he has had extensive experience writing for museum exhibits, including the dinosaur exhibit at NHM, meaning that he has practiced the art of writing technical material in a way that can be readily understood by nontechnical and diverse audiences.
This book can be considered an extension of the exhibit at the museum, taking what is there and expanding upon it considerably, forming an extended guidebook. It is not a catalogue of dinosaurs, though, such as Brusatte and Benton’s Dinosaurs. This book places dinosaurs in context within their world, focusing more on what dinosaurs were and how they lived over listing the different types, although it does that as well. More importantly, it talks about how paleontologists came to the conclusions they have, what is the evidence for what we think.
While extensively illustrated with a wide array of photographs of real fossils, paintings and illustrations of reconstructed dinosaurs, and the people and places, it is not a picture book. The text is extensive, but easily readable and should be readily accessible by any interested kid of middle school age or beyond, while still being a good read for adults.
The book has ten chapters broken up into an introduction to dinosaurs and the Mesozoic Era, five chapters on the lifestyles of the dinosaurs, an obligatory chapter on dinosaur extinction, a chapter on the history of dinosaur research, a chapter dealing specifically with how paleontologists piece together the clues to interpret the fossils, and finally ending with the now seemingly obligatory chapter on the evolution of dinosaurs to birds.
Chapter one is noteworthy for its debunking of some popular myths about evolution in general and dinosaurs in particular. It starts immediately with dispensing with the old chestnuts of “survival of the fittest” and the idea that dinosaurs died out because they were not “fit”. They properly describe evolution as being a product of those who are more capable of surviving in a particular environment and successfully reproducing, not necessarily the biggest and strongest. They go on to discuss what types of fossils are found and how they are formed which, while in general good, neglects the important contributions of microbes to the fossilization process. But to be fair, we know much more about that now than we did then and the purely physical processes listed here are still described the same way in almost every book published today. They also do a good job describing what a dinosaur is and is not. They separate animals commonly thought to be dinosaurs, such as dimetrodons, pterosaurs, and marine reptiles, from true dinosaurs. The biggest problem with this section is that the illustrations are poor. The Tyrannosaurus would not pass muster in the first edition, much less now, and the Deinonychus is out of date. Moreover, they continue to use the term “mammal-like reptile”, rather than the more accepted term synapsid, which makes this section appear severely dated. They still use the term “thecodont” to describe the earliest archosaurs that led to dinosaurs, although they at least do say it is an informal term, not one that is formally accepted. The problem with thecodont as a term is that it throws everything with a similar jaw together, whether or not they are related. The bulk of the chapter is a good, but necessarily brief description of the Mesozoic Era, including the position of the continents, the changing climate, and the evolution of plants and animals during this time, focusing of course on the dinosaurs, but not to the exclusion of everything else, which provides the necessary context for dinosaur evolution during this time.
Chapter two is all about movement and tells the story of how dinosaurs went from a lizard-like sprawl to a fully erect posture and the advantages that gave. There is discussion of some of the evidence we have for different gaits and stances, including a lot of discussion about trackways, as well as the diversity in the ways an erect stance has been utilized. The stories of early ideas is an interesting read, although they make one serious error by saying all sauropods had their nostrils on the top of their heads, when in fact they had their noses at the end of their snouts like every other terrestrial animal. I also think they give too much time to the debate over whether or not tyrannosaurs were scavengers or hunters, even though they do eventually come down on the side of hunters, as pretty much every paleontologist does. The tyrannosaur as scavenger debate was getting a lot of press during the time of publication, but it died down pretty quickly, with no one really accepting it anymore, considering there is evidence of active hunting by tyrannosaurs. Go to the Denver Museum of Nature and Science and you will see an edmontosaur with a healed bite taken out of its back.
Chapter three discusses food, how different dinosaurs ate, so one can expect several pictures of skulls and teeth. This chapter gets high marks for discussing current research at the time, such as Emily Rayfield’s work using Finite Element Analysis to determine bite force in several dinosaurs. Criticisms of the chapter include too much credence given to the idea that tyrannosaurs were scavengers which they revisit in this chapter, the discussion of neck posture in sauropods, and missing an important aspect of the tyrannosaur coprolite studies. These criticisms are mostly due to advances since the book was published, not a fault of the authors. The neck posture study has the problem of not sufficiently allowing for cartilage between the vertebrae, nor the fact that living animals bend their necks farther than allowed by that study on a regular basis. The tyrannosaur coprolite study also found remnants of muscle, which indicates a short digestion time. This is a strong indicator of an endothermic animal. Either that or an animal suffering some serious diarrhea. Finally, the chewing cycle of hadrosaurs is no longer as accepted as it was then. Casey Holliday makes a good case that the bones of the skull thought to move during chewing were really much better bound together in life, the supposed joints more an accommodation of quick growth, not for chewing (sadly, the link to the pdf of the paper in the linked article is no longer valid, but the article provides a good summary of the paper).
Chapter four is attack and defense. Interestingly, this chapter discusses tyrannosaurs as hunters, ignoring the scavenger discussion of the previous chapter, providing some indication on where the authors fell in that debate. This chapter does a great job of discussing different techniques for combat and predator avoidance. High marks to this chapter for balanced discussion of current research. I particularly liked the discussion about the role of color in camouflage and display. The biggest gripe about this chapter is the presentation of theropods like Troodon as scaly when we know they were covered in feathers. It doesn’t change the discussion in the text, which is still valid and interesting, but it is a flaw in the presentation.
Chapter five is about social organization, a topic not often covered well in books like this and is possibly my favorite chapter in the book. There are some interesting discussions here that will make one think about these animals as living animals within an ecological context. I would note that there is more evidence of group behavior of tyrannosaurs than was known at the time of publication, so they may have been more gregarious than thought then. I would have liked a bit more explicit discussion of the possibility of Deinonychus as opportunistic groups rather than a cohesive pack, but the discussions do a great job of keeping facts that we know and speculation about behaviors.
Chapter six is titled “Living animals”. This chapter gets into the detailed work of anatomy and molecular studies used to figure out how the animals were put together functionally and metabolically, as well as what their anatomical details tell us about behaviors. It serves as a nice introduction to the real work of paleontologists as more than just digging up fossils. It is a nice chapter and a great read. There are a few things that are a bit off, but not much. They discuss the discovery of actual soft tissue reported from a few dinosaur bones, such as proteins, blood cells, and blood vessels. They do not mention, however, that not everyone accepts those discoveries, instead concluding that what was found were more modern bacterial traces and not dinosaur soft tissue. Nevertheless, it is a good inclusion in the chapter. Our understanding of just how many dinosaurs had feathered has also grown dramatically since the book was published. Few people took the idea of a feathered, adult tyrannosaur seriously ten years ago, but we now have evidence some large tyrannosaurs were indeed feathered. They also make determining brain size in dinosaurs sound much easier than it really is because the amount of non-brain material in the cranial cavity varies substantially in animals other than mammals and birds. The evidence of color vision in dinosaurs, on the other hand, is stronger than presented in the book and we can pretty securely state that dinosaurs had not only color vision, but better color vision than we do. The book also uses a picture of a tyrannosaur with ridiculously large olfactory lobes that we now know is wrong. Tyrannosaurs had large olfactory lobes, indicating a good sense of smell, but they weren’t as large as presented in the book. The book devotes a decent chunk of space to the question of thermoregulation, although it is still necessarily brief, which they acknowledge, as it is a complicated discussion. For what space they have, they did a good job. I would say the idea of dinosaurs being endothermic for the most part is more accepted now than at the time of publication with new evidence pushing the debate in that direction.
Chapter seven concerns the mass extinction at the end of the Cretaceous. It does a good job of discussing the extinction event, including what did NOT go extinct, which complicates the picture. The evidence of a massive impact has been firmly established even more so than when the book was published. The role it played and whether it was the sole cause or the giant nail in the coffin, adding to the volcanism and changing climate, is still debated.
Chapter eight is called “Dinosaurs and people” and is mostly a short history of dinosaur discoveries. Chapter nine discusses what it takes to go from a discovered fossil to an understanding of the life and relationships of the animal in question. Between this chapter and chapter six, the work of paleontologists is given a good accounting and should make for a useful read for any budding paleontologist. What has been added since is a huge increase in technology which has increased data sharing, allowed people to form collaborations easier, and made modeling and experiments much easier, allowing more people to make significant contributions.
The final chapter discusses the evidence that birds are dinosaurs. The book discusses several feathered dinosaurs, but our knowledge of them and the diversity of feathered dinosaurs has grown by orders of magnitude since then. We have even found evidence of melanosomes, subcellular organelles that provide the pigment, which has allowed the determination of color in a few cases. The chapter has a good section on the origin of flight, providing the classic hypotheses, but also includes newer ideas that have greatly added to our understanding of flight, making the old hypotheses incomplete, with portions of both providing a much better answer. The book does state one thing that I would cross out. They state “It seems likely that a simple insulating cover arose first and was later modified for display, signalling, and finally flight.” This is a common belief even among paleontologists, but it is simply wrong. It is highly unlikely that feathers first arose as an insulating cover as the initial stages would have done the exact opposite of providing insulation by increasing surface area without a concurrent increase in insualtion. It is far, far more likely that feathers evolved for display purposes and were then adapted for insulation.
The book ends with a section providing data on several specific dinosaurs, a glossary, suggested sources for further reading, and a useful index.
In summary, the book is a great read. It provides an excellent look at dinosaurs as more than a stamp collection of strange creatures, but as living animals within the context of a real ecosystem. The book gives a better view of the real work of paleontologists than you will find in almost any other source. There are several places in which the science has advanced, making some specifics here and there in need of updating, but the meat of the book is still solid and provides substantial benefit to interested readers. It provides commentary in a much more thoughtful manner than is found in most other books and will make the reader think about concepts in a way rarely seen. The book shows science as a dynamic, changing field where no matter how many answers you get, there are always more questions and every piece of data requires a reexamination of the answers you already have to see if the answers are still valid. Dinosaur science is not extinct, it is still evolving and you definitely get that feeling here.
Now that Labor Day has come and gone, everyone should be back to school by now. I have been absent for much of the summer and not posted nearly as much as I had hoped to. I have been working on some projects which I hoped to have up by now, but are still in process. Working two jobs right now while trying to maintain some semblence of a personal life has left me precious little energy to work on Paleoaerie. But hopefully, that should end soon and I will be back to posting on a regular basis.
In the meantime, there are some news and upcoming events I would like to share so you can put them on your calendar.
- I have received the audio for my talks at the Clinton Presidential Library. Unfortunately, the video was not successful. So as soon as I get the chance to sync the audio to the powerpoint, I will post it here.
- I have joined forces with TIES, the Teacher Institute for Evolutionary Science, sponsored by the Richard Dawkins Foundation for Reason and Science. They have a number of excellent resources on their webpage and will allow an improved opportunity to offer workshops on evolution to teachers and other interested parties. These workshops are designed by teachers for teachers and are aligned with the Next Generation Science Standards. If you are interested in a workshop, please either contact me or Bertha Vasquez, the TIES Director. You can also find them on Facebook and Twitter.
- I will be appearing at the Forest Heights STEM Academy in Little Rock on Friday, September 11, to discuss how the scientific method is really used by scientists.
- I will be appearing at the next quarterly meeting of the Arkansas STEM Coalition meeting on September 25 to talk about TIES and National Fossil Day.
Speaking of National Fossil Day, make sure to put Saturday, October 17th on your calendar. The Museum of Discovery is hosting the second annual National Fossil Day event, even bigger and better than last year. Don’t miss it. National Fossil Day is a part of Earth Science Week, sponsored by the American Geosciences Institute, designed to “help the public gain a better understanding and appreciation for the Earth Sciences and to encourage stewardship of the Earth.”
Now that all the business is out of the way, I will get on with more educational material. In honor of everyone going back to school, I thought I would start a few posts about some definitions that most people generally get wrong. Today, I am going to discuss a few of the types of scientists that study past life.
Whenever a scientist tells people they are an archaeologist or paleontologist, they tend to brace themselves for the almost invariable questions about the other field. In most people’s minds, all the different sciences seem to be interchangeable, with little understanding that just because someone studies the past, they don’t necessarily study everything in the past. I won’t even get into the difference between scientists who study past life and historians. I will leave that for any archaeologists who wish to tackle that issue. I get this question so often that I bought this Tshirt.
Even though we all study past life, there are important differences. Here is a Venn diagram I created that may help explain how they differ.
As you can see, there are two main divisions in scientists who study past life: those who study humans and those who study everything else.
Anthropologists study humans, so don’t ask them about dinosaurs or mammoths or giant sharks. Don’t bring them a fossil you found. If you find a pottery shard or an arrow head, find an anthropologist. If you found a book, you might also try a historian. Ok, I said I wouldn’t get into this, but maybe just a little bit. Historians deal with written human history. So one might say that historians are a subset of anthropologists, in that they only deal with relatively recent anthropology. Many would also argue that they should not be included at all because they do not approach the endeavor with a scientific approach. While I can see the point, I can also see the point that this would also include many anthropologists, so comes across as sounding like the argument about can bloggers be considered journalists. The correct answer is that it is not as simple as that. But it’s not my field and my view of the topic is strictly as an outsider.
Paleontologists study everything that does not include humans. So please feel free to ask us about extinct organisms, as long as they don’t make pottery or arrow heads.This doesn’t mean to say that every paleontologist studies all extinct organisms. There are innumerable specialities within the field. If you ask a paleoclimatologist to identify a bone, he won’t have a clue what you are talking about. They study past climates, not bones. Just like one wouldn’t ask a podiatrist (foot doctor) to do brain surgery, don’t expect an expert in Pleistocene pollen to help you identify which type of trilobite you have, although I expect they could tell you that you do indeed have a trilobite.
But what do you do if you find a fossil of a hominid, something not quite human, but not quite an ape? That is where paleoanthropologists come in. They deal with that intersection between paleontology and anthropology, where the lines blur into shades of grey. In point of fact, all these terms are arbitrary boundaries and only serve to help us break up the studies into something manageable. Like everything else in nature, we have taken a continuous spectrum and cut it into defined sections to satisfy our need to categorize everything.
Even though there is far more life that is not human than there is that counts as human, for obvious reasons. The study of humans is more discussed than anything else. So while it is not my field, i will attempt to separate the major divisions within anthropology. Anthropologists, as mentioned study anything to do with humans. This can be broken down into two main categories. Physical anthropologists study the biology and evolution of humans. If you have human bones, they are the ones to talk to. Cultural anthropologists study human culture, their behaviors, what they make, how they interact with others. If it’s not a bone, but related to humans, ask a cultural anthropologist.
But what then are archaeologists? Do they not do the same thing as anthropologists? Yes, because they are anthropologists. They are just a subset that happens to be so well known that many people lump archaeologists and anthropologists together as if they are the same thing. But they aren’t, not quite. All archaeologists are anthropologists, but not all anthropologists are archaeologists.
Archaeologists study past human life through physical remains. Thus, they include some of both physical and cultural anthropology. They are the ones to talk to about pottery shards, arrow heads, and the like. Any physical evidence of a preexisting culture could be brought to the attention of an archaeologist. However, anthropologists cover a lot more ground, so to speak. There are cultural anthropologists that study current, existing culture. This is in fact a large field within cultural anthropology. There are even physical anthropologists that study evolutionary changes taking place within humans right now. Neither of these would count as archaeologists though.
Just as in anthropology, as I mentioned earlier, there are several different subspecialties within paleontology. Here is how the University of California Museum of Paleontology breaks it down.
Paleontology is traditionally divided into various subdisciplines:
- Study of generally microscopic fossils, regardless of the group to which they belong.
Paleobotany: Study of fossil plants; traditionally includes the study of fossil algae and fungi in addition to land plants.
Palynology: Study of pollen and spores, both living and fossil, produced by land plants and protists.
Invertebrate Paleontology: Study of invertebrate animal fossils, such as mollusks, echinoderms, and others.
Vertebrate Paleontology: Study of vertebrate fossils, from primitive fishes to mammals.
Human Paleontology (Paleoanthropology): The study of prehistoric human and proto-human fossils.
Taphonomy: Study of the processes of decay, preservation, and the formation of fossils in general.
Ichnology: Study of fossil tracks, trails, and footprints.
Paleoecology: Study of the ecology and climate of the past, as revealed both by fossils and by other methods.
Each one of these can be broken down into even more specific specialties. Paleoecologists can specialize in biogeography, limnology, pedology, tempestology, schlerochronology,and many others. Vertebrate (and invertebrate) paleontologists can specialize in taxonomy, systematics, functional morphology, etc., but I think you get the point. There is far more that can be studied by any individual. paleontology, like any other science, is a team sport.
There are no hard and fast boundaries between these of course. Vertebrate and invertebrate paleontologists can and do study taxonomy, biogeochemistry, paleoecology, and taphonomy, and others all at the same time. Paleontology is highly interdiscplinary and requires knowledge in a lot of different fields. But many scientists tend to spend most of their time in a specific area.
So if you have a question, you will get the most detailed answers from someone in the right specialty. Choose wisely and you will get your questions answered. If you don’t, go to grad school, discover them for yourself and let everyone else know about it.
Chase, from Odyssey of Time (nice blog, check it out), guessed the answer for this puzzle. See below for what amazing animal this picture represents.
If one thinks about cliff-diving geese, nothing fits the bill better than barnacle geese, also known as Branta leucopsis. They live in the North Atlantic and can be found along the coasts and islands around Greenland, the United Kingdom, and most recently in the Baltic Sea around some of the Nordic countries.
The day they are born they face a daunting task. To protect the eggs from predators, the adults make their nest high up on cliff faces, oftentimes 400 feet (150m) above the base of the cliff. Unfortunately, the food is at the bottom of the cliff and the parents do not bring food to the chicks. So what is a hungry newborn to do? They jump.
It’s a rough life. Between the dangers of the fall, the predatory birds above, and the foxes below. they are fortunate is half of the chicks survive their first day. Personally, I don’t see how any of them survive. The fall is just brutal. Listen carefully to the video and you can hear the chick squeak as it hits the rocks repeatedly on the way down. Amazingly, the chick just brushes itself off and carries on, a little dazed, but seemingly no worse for wear.
Sir John Mandeville, in the 14th century, had an interesting view of them. According to Sir Mandeville, “in our country were trees that bear a fruit that become birds flying, and those that fell in the water live, and they that fall on the earth die anon, and they be right good to man’s meat. And hereof had they as great marvel, that some of them trowed it were an impossible thing to be.”
it is truly amazing how easy it is to completely fall out of a routine if you break it for any stretch of time. Fortunately, or unfortunately, it is also often just as easy to fall back into it. in this case, I am hoping it will be easy to get back into writing for Paleoaerie after my unexpected extended break. There is much that will be coming as soon as I can. most notably the recordings of talks I gave at the Clinton Presidential Library in Little Rock, AR in the past month or so. One is on engineering a dinosaur, given just in time for the opening of Jurassic World. Speaking of Jurassic World, it is a great monster movie, as long as one is not looking for accuracy in its dinosaurs. But as the geneticist in the movie states, the real dinosaurs would have looked considerably different, but they wanted bigger, scarier, with more teeth. The other talk is on Arkansas fossils and why we need a natural history museum in Arkansas.
For now, I will just leave you with this puzzle. The pictures represent one of my favorite extant animals, simply because their young are so incredibly amazing. Leave your guesses in the comments section and stay tuned for the answer.
Last week I posed this challenge. What real animal combines traits from the kiwi, anteater, and hedgehog. Chase and Herman Diaz came up with the correct answer.
The animal that has the traits of these three animals is the echidna, also known as the spiny anteater. Named for the “mother of all monsters” in Greek mythology, the real echidna looks like a combination of other animals, much like the mythical Echidna herself, who was part woman, part snake.
When people think of weird mammals, echidnas are very often at the top of people’s lists. It has several traits that are commonly mentioned. First, it is a monotreme, a group of mammals that lay eggs. Today, monotremes consist only of echidnas and platypuses, but in there were several others in the distant past. Platypuses are so strange that people at first thought it was a fraud. Who would believe an egg-laying mammal with the face of a duck?
Second is their fur, which has numerous sharp spines, similar to that of a hedgehog. Because these spines are modified hairs, they have limited control of them. Just like other mammals can make their hair stand up (humans know this chiefly as “goosebumps”), the echidna can make its spines stand up, although they can’t shoot their spines like some people would have you believe.
That fact the echidnas lay eggs makes their reproductive system rather different from almost all other mammals. Internet sites always want more people to click on their site, so echidna reproduction gets a lot of discussion. An internet search will immediately turn up comments and pictures of the four-headed penis of the males and the fact that the females have no nipples, instead feeding their young (called puggles) through glands in their pouches (yes, they have pouches like marsupials) which secrete the milk that the young lap up. You can even find talk of the mating trains echidnas can form during mating season, in which the males form a line behind the female and follow her around for upwards of six weeks until she finally decides to mate. Then they dig a trench around her, jump in and try to push each other out like some sort of bizarre sumo contest. The last male still in the trench wins the right to breed first.
Much like many reptiles, which have what is termed a hemipenis (a two-headed penis), the male echidna only uses half of its penis at a time. In the echidna’s case, that means that they use two out of the four heads at any one time, which is good, because the female echidna has two uteruses. We’re still not done with the weirdness. Because the female may mate with several males, the sperm joins into one large mass, a super-sperm if you will, that together, can swim faster and stronger than any of them separately.
There are several traits that the echidna shares with the platypus, in addition to laying eggs. The echidna is edentulous, meaning it has no teeth. It does, however, have an incredibly fast tongue; able to slurp up the ants, termites, and other insects at the rate of 100 licks/minute; thus its name Tachyglossus, which means “swift tongue”. It also has a very sensitive beak that is electroreceptive, meaning it can detect the tiny bioelectrical signals given off by the insects for which it forages. Additionally, echidnas have a spur on its hind legs, although unlike the platypus, it is not venomous.
So what does it mean to be a monotreme? The Tree of Life web project has an excellent and clear summary of what a monotreme is scientifically. Evolutionarily, the monotremes are the oldest true mammalian lineage, splitting off the line that led to placental mammals sometime around 200 million years ago (as a point of reference, the oldest known dinosaur was found in rocks dating to 230 million years ago). Much of what we consider to be mammalian had yet to evolve by this point, so there were still several traits monotremes shared with reptiles that were derived from the common ancestor of both the reptiles and mammals. This split was so early in fact, that the middle ear bones developed independently from other mammals.
My personal favorite of all the strange things about the echidna is its thermoregulation. When people think of mammals, besides for milk glands and fur, they think of “warm-bloodedness”. Thermoregulation is far more complex than most people realize. There is much more than “warm- or “cold-bloodedness”. Better descriptions of thermoregulation are endothermy (temperature controlled internally)/homeothermy (maintains constant temperature) and ectothermic (temperature strongly influenced by environment)/poikilothermic (temperature fluctuates). But these are just endpoints on a spectrum. Perhaps no other animal illustrates the variation better than the echidna.
The echidna does it all. At various times, the echidna displays endothermy, ectothermy, homeothermy, and poikilothermy. It hibernates, it goes into torpor on a regular basis. The echidna is also a eurytherm, meaning that it can operate just fine at a variety of temperatures without loss of function or activity levels. Whereas most mammals would lose function and coordination if their bodies cooled even a couple of degrees and would completely shut down if they cooled ten or more degrees, the echidna gets along just find even when its body cools to 20 C (that is 68 F for those in the US, a temperature at which we would be long dead).
Needless to say, it is a heterothermic animal. Heterothermy is when an animal lets its body temperatures fluctuate. While it is a broad term that includes poikilothermy, it is typically distinguished from poikilotherms by being under the control of the animal and/or by being regional, meaning that different parts of its body have different temperatures. The classic example of this is the deer, in which the legs are allowed to get cold while the body stays warm. African elephants do this somewhat in reverse, shunting blood to their ears allowing them to heat up, thereby dumping heat from their core body to their ears, which can then cool off more readily due to their large surface area. Of course, few mammals can beat the camel, allowing their temperatures to vary as much as 7 C throughout the course of a day.
Anyway, back to the echidna. Check out this graph. In this study, the researchers measured the body temperatures of a female echidna for 13 years. The graph shows temperature ranges for one year. Another study found that the echidna typically maintained temperatures when active at around 32-33 C (as compared to our 37 C) and dropped to 27-28 at night when it was inactive, although it could drop to as low as 4.7 C and still get up and have normal activity during the day. This variability not only allows it to use less energy, but it also allows it to tolerate temperatures as high as 42 C. Starting the day cold allows it to absorb more heat during the day without overheating. And it is not just its temperature that it allows to vary. The echidna can vary its metabolic rate while still maintaining its normal activity levels. Of course, when it needs a stable body temperature, like for instance, when it is incubating an egg, it can do that too.
All told, the echidna is a pretty amazing animal. It is also about as close as we are going to get in a living animal to see what our mammalian forebears were like in the early years of mammalian existence.
The natural world can be a very strange place. WTF evolution?! is a great site that takes a humorous look at some of nature’s weird turns. Today I am going to celebrate some of nature’s curiosities by playing a game. Some animals are so weird they look like combinations of other animals. For instance, the platypus is often said to look like a cross between a duck and a beaver. I will provide a fictional cross between a set of animals. See if you can guess what real animal it might be. Then come back later to see what animal it is and description of what makes it such a curious animal.
For today’s cross, what might you get if you cross a kiwi (the bird, not the fruit) with an anteater and a hedgehog? I will give you a hint. It is an extant animal, so you can rule out any fossil animals.
Last week we posted a new fossil. Were you able to figure it out?
This particular picture is of the ant, Nylanderia vetula, caught in Dominican amber. Dominican amber is from the Miocene, currently thought to be about 25 million years old. The fossil ants from Arkansas are a bit different.
In 1974, ants were found in amber collected near Malvern, Arkansas, from the Claiborne formation, which is listed as being from the Eocene, roughly 45 million years ago (give or take 3 million years). According to the Arkansas Geological Survey, the Claiborne is a series of fine sand to silty clay layers, with interspersed layers of lignite. The lignite and amber are clearly indicative of terrestrial environments, although there are some marine sediments within the formation. A number of fossils have been found in the formation, including fish and reptile bones and teeth, leaf impressions, trace fossils, and of course, wood and amber.
The specific ants that have been found were identified as Protrechina carpenteri. These ants are in the group Formicinae, one of the more common ant groups. Interestingly, the Eocene ants were anything but common. Ants during this time shifted from the earlier ants to a more modern collection of species. They were quite diverse, with Phillip Ward reporting that David Archibald claimed some of them were the “size of small hummingbirds”.
Images of our Arkansas fossil ant are hard to find, as in, I couldn’t find a single image. However, if you want to see the real thing, go to the Harvard Museum of Comparative Zoology, where Antweb.org reports it is being held. Yet another Arkansas fossil in the hands of another state.
For those of you who are new to the website, under the Arkansas Fossils tab is a list of fossils that have been reported in Arkansas. For those of you returning to the site, you will find a new addition to the page. Using the Arkansas Geological Survey regions map, I have marked where in the state fossils have been found. Want to know where to find conodonts? Looking for dinosaurs? Check the map to get a general location.
At some point, I would like to make the map interactive, so that visitors can click on the map and be taken to information about that fossil. Unfortunately, I do not yet have the technical ability to do that for this WordPress template. Should someone find such task within their abilities and has an interest in contributing to the site, please contact me.
Here is the map you can find on the fossils page.
Time for a new Mystery Monday fossil. The fossil on display here was found in Dominican amber, as well as Russia. But it has also been found in Arkansas and played a role in our understanding of the evolution of this group of animals. Leave your identifications in the comments section and come back Friday for the answer.
I have been going to Mid-America Museum in Hot Springs, AR for many years now. I even got married there. Nevertheless, there were a few things that always frustrated me. They had a mastodon skeleton in the entry way, which was great, but there was no real signage with it. It was just there, with no context at all. But more than anything else, I despised the sign they had next to a sauropod track next to the mastodon. Two incredible dinosaur trackways have been found in Arkansas and Mid-America is one of the few places you can see anything of the trackways. But the footprint, again, had no context and the sign had the sauropods wading around in swamps, straight out of a 1950s drawing. I repeatedly told them about the sign, I even offered to make them a new one, but to no avail.
So when I heard about the museum shutting down for several months to be completely renovated, I hoped they would fix some of these things. Mid-America Museum is now open again and I got the chance to visit it recently. My verdict? They did a great job, better than I even dared hope. Like anything else, there are still a few things they could do to improve it, but the earth science exhibits are well worth taking some time to go see them. It’s a completely new museum. You should definitely check it out.
To go along with the radical renovations, it is now the Mid-America Science Museum and Donald W. Reynolds Center. The Reynolds Foundation donated $7.9 million (most places say 7.8 million, but that is because most people don’t know how to properly round, most people just truncate, 7.88 does not round to 7.8), without which the renovations could not have been done. Many of the old exhibits the museum was known for are still there, such as the Tesla coil and moving art structures, but I am going to focus on the earth science exhibits here. There are many other places you can read about the other exhibits, such as this one.
The main exhibit focusing on earth science is called Arkansas Underfoot. It is located, appropriately enough, next to the Arkansas Underground tunnels. With this placement, the tunnel construction is thematically tied to the rest of the museum in a much better way than previously. The tunnels have been cleaned and fixed up. The frayed and broken sections of the rope bridges have been replaced with all new rope. I was disappointed to see that the skeleton of the miner has been removed, but the many appreciative comments from the kids indicates this was a good change. Apparently many kids found it frightening and disliked it. I am still not convinced the stated purpose of this exhibit to allow kids to explore and learn about life underground and what lies beneath our feet is at all effective. I enjoyed a small display of fossils embedded in the wall at one spot, but other than that, there is nothing educational inside and I seriously doubt many of the kids see it because it is situated in a spot that does not lend itself to stopping and looking. Nevertheless, kids really enjoy it and it brings people into the museum where they see other things that are truly educational, and it provides parents a bit of a respite as the kids zoom through it again and again, so it succeeds on that front. I do wish there was a bit more within it that might serve an educational purpose, particularly for the space it takes. I don’t advocate its removal, quite the opposite in fact. It should be added to in ways that enhance its educational value.
The mastodon and sauropod track are here, with the mastodon freshly painted to look more like the real bones from which the casts were made. It looks good and has more of a context with all the other exhibits nearby. The sauropod track has a new sign, which is a vast improvement over the old one. The swamp-dwelling sauropods are gone, replaced by a discussion of the Arkansas dinosaur trackways, including pictures. The trackways really are impressive, much more than they show here (in all fairness, to truly appreciate them would take an exhibit all its own, so what they accomplished here is perfectly reasonable given space constraints and exhibit balance considerations, it is quite sufficient for the intended audience without going overboard), but at least now visitors get a feel for the trackways as being more than an isolated footprint and the incorrect information from the old sign has been replaced with good information. The footprint now has that all important context. Outside still has the dinosaur dig that is popular with the kids, along with the adjacent track site, making a nice continuation of the interior exhibits.
There are several new exhibits to see which are well worth spending time to see. The exhibit that draws the most attention is an interactive 3D topographic map. Using a projector and an Xbox Kinect, they turn a simple sandbox into an endlessly changing map. As people move the sand around, they can see the colors change to match the topography, with snow-capped hills and rivers and lakes that respond to the changes in the landscape. Its draw and fascination is evident by the length of time people spend there manipulating the topography. It is a wonderful interactive display, but there are a couple of ways it could be improved. The actual topographic lines are very dim and go unnoticed by almost everyone, decreasing that educational aspect of the display. Despite a number of maps on display in the exhibit, there are no topographic maps for comparison other than the large map behind the mastodon. I discount that one because it is displayed as monotone wall art without reference to it being topographic in nature, so it runs under the radar for visitors. There is an empty wall right next to the sandbox. I think the exhibit could be improved by putting up a topographic map on that wall, along with a description of how to read it, using text that relates it back to the sandbox, thereby tying it all together.
Speaking of maps, there are several on display. A large geologic map of Arkansas adorns one wall, with explanations of how to read it, much like I suggested above for the topographic map. On the map are listed several places where mineralogical resources have been found and mined. Next to the map is a display showing some of the rocks and minerals that have been mined in the state that are shown on the map, as well as a display showing the major types of rock in the state. In addition, there is a table with several maps of various kinds. My favorite is the color map of the Mississippi river showing how it has meandered all over the area.
On the adjoining wall to the one displaying the geologic map is a series of display cases embedded into the wall showing different soil types, showing how soil changes with depth and region. One is called a Stuttgart soil, which is listed as the state soil of Arkansas. Who knew we even had an official state soil?
At the fossil station, you can look at real microfossils. There is a microscope which lets you see a variety of identified fossils such as shell fragments and echinoderm spines. The signs are good, informative without overloading visitors. The exhibit lets people see fossils that you don’t normally see in a museum and get a feel for the work involved. While I was there, several people examined the fossils and tried their hand at identifying them.
Next to the fossil station is a slice of soil that looks something like a giant ant colony display. Instead of ants and there tunnels, there is bacteria which turn the soil different colors depending on the type of bacteria and their type of metabolism. The signage is great and very informative. I have not seen a display like this before and thought it a great addition. The only criticism I would make is that the lighting is not the best. The lights shine up from the base of the display, so the lights are too bright to get a good look at the lower portion of the soil. You wind up trying to look almost directly at the bulbs between you and the bottom of the display.
Continuing on, there is a rock smasher, where people can drop a heavy weight onto rocks to see pieces break off and fall into a short series of grates separating the pieces into different sizes. I am not sure people were getting the point of the exhibit, which was explained on the adjacent sign, which talked rocks breaking up to form sand, clay, and soil. People seemed to like trying to smash the rocks, though, so hopefully some people looked over at the sign while they were doing so or waiting their turn. Curiously, the sign never actually mentions the word “erosion”, which is what the exhibit is all about.
Between the rock smasher and the dinosaur footprint is a large display of Arkansas quartz. Arkansas is famous throughout the world for its quartz, so it is fitting to see it on display here.
If I were to pick the one display that most surprised me, I would probably choose the taphonomy display. As someone professionally interested in how things decay and form fossils, I particularly loved this display. It is not something you see in museums very often. Taphonomy is the study of everything that happens to an organism between the time it dies and the time it is collected and studied. This display of course, only covers the first part of the process, showing five weeks of the decay of a freshly dead rat. I should warn people that it might be disturbing for some viewers. It is understandable they only go this far in the process, as it is the easiest to show and most relevant to active, biological processes that affect us. The touch panel next to the display allows people to go further into how the decay process fits into the function of a healthy ecosystem. Definitely worth a look. If maggots bother you, you can still learn a lot from the touch screen.
The final piece of the exhibit is a touch screen which allows you to take a virtual field trip through eight different areas of Arkansas, learning about the geology making each area unique and how the underlying rocks affect the landscape. It is well done and you can spend a lot of time going through the different trips. I didn’t have time to go through all of them, but I will definitely be spending more time at this panel the next time I go.
In conclusion, I think they did a great job on the renovation, filling in part of a huge, gaping hole in Arkansas museum coverage. There are still a few places that can be improved, like any exhibit, but what they have done is worlds better than before, providing exhibits you won’t find elsewhere in the state. Take a day out of your weekend and go see for yourself. It really is a new museum, carrying over the best of what was there before and adding in much that will fill your day.