Meat-eating Dinosaur Review

T. rex from Wallpaper Abyss

As much as sleeping in on a Saturday is a highlight to the week, there are some things worth waking up early for.  For me, a dinosaur lecture from a local paleontologist is just such an event.

Dr. Richard Kissel, from Ithaca NY's Museum of the Earth came to the MOST today to give a lecture titled "From Raptors to Rex: Meat Eating Dinosaurs."  This was part of the TACNY sponsored Junior Cafe Scientifique lecture series.  I've only been to a couple of these, as our Education Department doesn't help organize them, but I think they are one of the best things we have going on at the museum.  The idea is to bring in interesting topics that will connect with people of all ages, and to offer this for FREE and include FREE admission to the museum as well.  This winning recipe keeps the attendance growing, and today's lecture packed our IMAX theater with around 200 people attending.  I want to stress that these weren't just professorly types, but all kinds of members of the Syracuse community turned out.  If nothing else, this convinces me that Junior Cafe Scientifique is a success.

A lecture is only as good as the lecturer who gives it, and Dr. Kissel did a great job.  He introduced himself as a dinosaur loving kid who, though now grown up, never forgot to keep asking the question, "Why?"  The lecture was a chronological survey of carnivorous dinosaurs through the mesozoic era.  He talked about a lot of interesting things, and I want to mention five.

Herrarasaurus in the backround, mammals in the foreground.
Image Source: National Geographic, Artist: John Gurche

1.  Dinosaurs ruled this world for a long time - over 150 million years of dominance.  The Age of Dinosaurs was from about 230 million years ago to 65 million years ago.  That means that we, as humans, are living closer in time to the late Cretaceous  T. rex than the T. rex lived to the Late Jurassic dinosaur Stegosaurus.  And the early carnivore Herrerasaurus lived around 80 million years before Stegosaurus!

2.  Dinosaurs and mammals appear at the same time on Earth.  During the Triassic period, around 230 million years ago, the first dinosaurs and mammals evolved.  This is pretty interesting, because often people assume that mammals came only at the end of the Age of Dinosaurs.  They lived together for a very long time.  It is true, however, that the mammals during this time were all pretty small; the larger ones usually being about the size of an opposum.  

3.  Carnivorous dinosaurs grew new teeth throughout their lives.  If you ever get to look at a carnivorous dinosaur skull you may notice that the teeth are different lengths.  This is because some were just growing in while others were established.  I think part of me is always rooting for the carnivores, and I was glad to know that if they lost any teeth trying to hunt an uncooperative triceratops, they could just grow them back.

The Swing N Slide See Saw

4.  Large Carnivores are a balancing act - big head means small arms.  I remember that when I first learned about this idea it was an aha moment.  If you look at a bipedal (walks on two legs) dinosaur, their legs are like the fulcrum on a see saw.  Dinosaurs like the T. rex have such huge heads, that they risk becoming front heavy, and face-planting. Having smaller arms kept some weight off the front end.  As this trait developed over time, we can assume that hunting and feeding strategies must have changed as well.

5.  Birds are dinosaurs - or at least their ancestors were.  If you've ever taken any time to learn about dinosaurs in the last decade or so, you have probably heard this before.  I thought Dr. Kissel did a good job of explaining the development of feathers (T. rex probably had some) and flight in dinosaurs, and their evolutionary relationship to birds.  This topic could have easily taken the entire lecture, so I wasn't sure if he would cover it.  I'm glad he did, because his pictures and explanations helped me to understand this better.  The short of it is that dinosaurs and birds share some unique bone structures as well as a timeline that makes sense for their evolutionary relationship, but the new understanding of feathers has really been the clincher in this debate.

Sinosauropteryx and its striped tail.

In some ways, a bird is defined by its feathers (see here).  Until dinosaurs were discovered to have feathers too, birds held this feature alone.  Feathers are complicated enough that the idea of convergent evolution (both evolving independently in birds and dinos) seems unlikely.  But the real victory here is that we are now starting to piece together how and why feathers first appeared on dinosaurs and how they led to flight.  Having feathers and using them to fly seems like such a remarkable thing, that figuring out were they came from is rather difficult.  Features like feathers, eyes, or just about anything else an animal has must be assumed to have evolved naturally from random genetic changes (such as mutations) and natural selection (if your being scientific about it).  This means that these things don't come fully formed and that animals can't start working on developing feathers because they hope their descendants will learn how to fly.

So what have we found?  We see that the role of the first feathers appears to be for display and insulation.  Some were found as long feathers on the ends of dinosaur tails, while another example of early feathers even shows that dinosaurs had stripes.  One fossilized oviraptor specimen shows it using its feathers to keep its eggs warm (link here). 

We have examples of dinosaurs who are using feathers for gliding, and fossils of the mesozoic bird archeopteryx that look so remarkably like other dinosaur species it is easy to get them confused. Archeopteryx is so closely related to dinosaurs that is is still debatable if it could use its feathers for flight.  So it appears that as feathers developed for display and insulation, they eventually led to gliding, and finally to full flapping flight in birds.

I am not a paleontologist, but that is the story as best as I can make of it from Dr. Kissel's lecture as well as a number of other resources.

So if birds evolved directly from dinosaurs, does that make them dinosaurs.  According to paleontologists, the answer is yes.  When asked by the crowd to explain this further, Dr. Kissel even said that birds, according to modern classification rules, could be considered reptiles.  If you are interested in learning more about this topic, check out this site from Berkely.

Dinosaurs are such an interesting topic.  I sure am glad I didn't sleep in today.

P.S.  I couldn't resist posting an anti-feathered dino propaganda sticker.  I'm not sure how serious this is supposed to be, but I thought it was too funny not to post.  If you refuse to believe dinosaurs had feathers, you can even join the Facebook group.