Dr Andrew Cuff (Associate Lecturer in Anatomy at Hull York Medical School) gives us a whirlwind insight into the evolution and life of dinosaurs, what they looked like, and how we dig for their fossilised remains, as well as his work on ancient felids (cats). Please note, unless otherwise stated, pictures are from pixabay.com or unsplash.com, and are purely for illustrative purposes. Subscribe to my blog here.
Do you have a favourite dinosaur period?
Broadly speaking the Mesozoic Era (spanning the Triassic period: 250-200 million years ago, Jurassic period: 200-145 million years ago, Cretaceous period: 145-66 million years ago) was a hugely important time.
During the Triassic, the world is recovering from the largest mass extinction of all time and has a wide diversity of weird and wonderful species that evolve and try to fill some of the roles that were previously filled by the then extinct species.
The Jurassic is when dinosaurs really take over the world, and their marine reptile cousins dominate the seas. However, the Cretaceous is the specific time within that range I’d want to see most.
I’ve loved dinosaurs since I was young and somewhat boringly T. rex is my favourite dinosaur, so of course I want to go see it. And if I could safely watch the end of the non-avian dinosaurs with the impact at the end of the Cretaceous about 66 million years ago, who wouldn’t want to go?
So avian dinosaurs survived the end of the Cretaceous?
Birds are dinosaurs. They didn’t all die at the mass extinction at the end of the Cretaceous. We know this because we find a huge diversity of feathered dinosaurs, particularly from China that help show this. Although it is a surprise to many, we’ve known it since the discovery of Archaeopteryx, around 1861, which was during Charles Darwin’s lifetime.
What did dinosaurs look like?
We can tell the colour of some dinosaurs from their feathers and skin. In really well preserved specimens, the melanosomes (the pigment giving organelles in our cells) are still visible. Round ones give browns/oranges, and sausage shaped ones give blacks.
So, we know that some dinosaurs (Sinosauropteryx) were stripy from alternating regions with and without the melanosomes.
We know that Microraptor was nearly completely black, but also likely iridesced (produced different colours depending on the light shining on it). Think pigeon necks which show purples and greens even though there is no actual colour there.
An ankylosaur (the armoured dinosaurs with the big hammer-like tail), Borealopelta, is incredible. It’s a multi-tonne dinosaur fabulously well preserved so that we can tell it is counter-shaded i.e. the skin on top is dark and on the belly is light – think a lot of antelope in Africa. Counter-shading is used to help camouflage, so it suggests these massive dinosaurs were still very much in the food chain even at that size.
The Velociraptors in Jurassic Park should be covered in feathers too! Also they should be the size of the Dilophosaurus, and the Dilophosaurus should have been the size of the Velociraptor.
Speaking of ‘Jurassic Park’, can we use computer wizardry to analyse how dinosaurs might have moved?
Yes. Let’s use a study we published last year as an example.
We looked at a dinosaur called Mussaurus. It belongs to the group called the sauropodomorpha. Most people know the later sauropods, the massive, long-necked, long-tailed dinosaurs like Diplodocus, Brontosaurus etc. Mussaurus was an earlier member which hadn’t yet reached great sizes.
We have a growth series from hatchlings all the way up to adults, and can reconstruct their skeletons, and then put flesh back on them. Using some clever maths, we then calculated their centre of mass.
This was then used to show that the hatchlings walked on all 4 limbs, whilst the adults shifted to walking on just their hindlimbs. It’s a fascinating transition, and today we think only humans do something similar.
Why are there more fossils of immature than fully mature dinosaurs?
Dinosaurs are much like all other animals. They produce a huge number of young because so few get to adulthood. This is due to predation, disease, and nutritional requirements.
It is possible dinosaurs had even higher mortality rates for their young due to their extreme growth rates and the food that must have been required, particularly for the largest species.
Did they really have tiny brains? And does that equate to stupidity?
It is true that many dinosaurs had relatively small brains particularly for their body size. This is true even for most of the assumed “intelligent” species such as the raptors.
This does not mean they are stupid, but may have implications for group hunting, and a recent paper suggests that it is highly unlikely they hunted in groups.
That being said, birds are living dinosaurs, and some of them are amongst the most intelligent of living species. Corvids (the family that includes crows), are known to be able to fashion tools and solve complex problems. Underestimate their intelligence at your own risk!
Have you been baffled by any fossils you’ve come across?
Spinosaurus will forever be an enigma and an annoyance to me. It was the first species I published on so will always have a place in my heart.
For those who aren’t aware of what Spinosaurus is, it was a giant dinosaur from North Africa, with a sail on its back, a thick tail, and a very strange skull. It featured in Jurassic Park 3, although that reconstruction has changed several times in the years since.
The original fossil was found in Egypt, but was destroyed during WW2 in a bombing raid on Munich. Several more specimens have been found, but because we cannot compare it to the original, it is tough to say if they are the same thing and exactly how the relate.
All I can say is that the more we find of it, the stranger it seems to become!
How did dinosaur lifespans compare to today’s animals?
We honestly don’t have great estimates for the oldest a dinosaur could reach.
Dinosaur bones, like trees, develop rings which can be used to count their age. However, when they get to adulthood some of their earliest rings start getting destroyed as marrow cavities develop, so we can only estimate the age of those oldest individuals.
For example, the oldest known Tyrannosaurus rex is about 28, but they may have been able to get older. Some suggest the sauropods may get much older, possibly 100 years or more, but there is no evidence to support this yet.
Are there any ‘living fossils’? Crocodiles?
The assumption that some species are “living fossils” unchanged over tens or hundreds of millions of years is a misunderstanding of evolution. No species has survived exactly as it was millions of years ago.
Every generation has some change due to how the genes are mixed during sexual reproduction. We do not look exactly like either of our parents, but we share similarities to both.
If we were to go back a dozen generations these similarities would be much harder to see, but we would still all be humans. If we went further back, you would also find it impossible to find the exact generation where we were no longer Homo sapiens and instead one of our earlier relatives.
Slow and subtle changes are still happening in all living species, even if some of them look similar to fossils from millions and hundreds of millions of years ago.
Can you give us some examples of more recent human evolution?
In the last tens of thousands of years humans have evolved the ability to consume milk (lactose tolerance, although only certain populations), and various genetic conditions that reduce the impact of malaria (such as sickle cell traits).
These characteristics provided selective advantages to those who had them. For example, we now find sickle cell traits widespread in regions with malaria, where it provides immunity, but the trait’s prevalence rapidly declines outside of malarial regions.
Modern medicine, and our cultures have meant many more people survive and reproduce than used to, and it is arguable that our culture is what is now primarily evolving. However, these cultural changes do have physical implications.
For example, modern generations are amongst the tallest ever, our jaws are increasingly gracile and we have more problems with impacted wisdom teeth (and some people not even having them anymore).
Who knows what our species will look like in thousands of years!
I understand you’ve 3D-printed a crocodile. What’s next on the printing menu?
The 3D-printed crocodile was a personal challenge. I tried to make it into a museum style mount and was fairly pleased with the results. The files are all available online if anyone wants to have a go, or even improve upon my design.
As for what I would like to print next, I would like to print my own skull. I have often wanted to do outreach events showing how we can reconstruct the soft tissues on skeletal remains. I would love to have the public attempt to reconstruct a face from a known skull, and then they can compare their results to the actual face. In this case, mine.
You also study and research felids (cats). When did they evolve?
The first cats evolved around 25 million years ago, and the first big cats several million years after that.
You’ve looked at how the style of felid mobility doesn’t change much with size. Why is this?
Because of how muscles scale with increasing size, large animals are usually relatively weaker than small ones. To compensate, animals tend to change their posture becoming more upright (straight legged) as they get bigger.
If you look at a mouse you will see it moves and stands with its legs bent, whilst elephants have almost completely straight legs under their bodies.
Cats don’t follow this change with all felids having the same crouched posture from the smallest cat to the largest tigers and lions. With big cats being relatively weaker and not changing their posture, they are actually worse at walking and standing efficiently.
Why then would they keep the crouched posture? The crouched posture helps with rapid acceleration as is needed in all cat ambush hunts. Being inefficient at other behaviours may explain their “laziness” and why big cats sleep up to 20hrs a day.
Could you give us a brief overview of a typical day on a dig?
A typical dig day depends heavily on what you are doing.
It will always begin early at the crack of dawn so that you can get breakfast and make sure you are fully hydrated. Then you are on the way to either your dig site or where you are going prospecting as soon as you can to make the most of the sunlight.
If you are digging you are usually excavating, initially with big tools (pickaxes/shovels) and then down to knives/dental tools when you are close to the bones. You then wrap them with wet paper towel before covering that with burlap and plaster. This hasn’t changed much from the 1800s.
There is usually an hour or so in the middle of the day to relax during the peak of the heat, and then it’s working until 5 or 6 in the evening. Then, it’s back to the camp/accommodation for food, often a beer, and then to bed.
If you are prospecting the only real difference is usually less digging and a lot more walking as you search the area for either whole bones, or more usually the little exploded fragments of bone that have eroded out from the hills. You follow the bits back up the hill to find the source and hopefully a lot more bone!
What propelled you into palaeontology?
I, like many other kids, got into dinosaurs when I was young. I can vaguely remember getting a book from my uncle about dinosaurs aged about 4. It may not have been the first one, but it’s the first one I remember. Don’t ask which one as I can’t remember the title anymore.
Around that time, or within a few years, an aunt took me fossil hunting on the Jurassic Coast in England, at a place called Charmouth, and I found my first fossils. The rest is sort of history, but definitely not without a lot of support from my parents who encouraged my passion and didn’t try to turn me to banking/law.
What is your favourite book?
I don’t have a single favourite, and read a weird collection of pop-sci books.
I really enjoyed I Contain Multitudes by Ed Yong. I’d also recommend A Brief History of Everyone Who Ever Lived by Adam Rutherford, Tamed by Alice Roberts, The Dinosaur Hunters by Deborah Cadbury, Bad Science by Ben Goldacre and the Invention of Nature by Andrea Wulf.
What is the question that keep you awake at night?
At the minute there are many. I am in my first teaching role, and concerns about students during Covid-19 lockdowns are weighing heavily. Are they okay, how can we support them more to complete their theses etc.?
My job uncertainty is another. Academia is an unpleasantly unstable career choice. I am not trying to put people off their passions, just trying to be honest. I did a PhD, 6 years after it in research, and am unable to find a permanent post. My current contract is 2 years teaching, so where will I be next? Will this job become permanent? Covid-19 hasn’t helped allay those concerns as most universities are warning of dire financial circumstances.
Academically, I think beaks are incredibly interesting. All birds today possess a beak. Layers of keratin (like your fingernails) sitting on skin and bone. Such a simple structure, yet birds have modified it in a huge diversity of ways, from hummingbirds, to toucans, parrots and ducks. They are vital for procuring their food and manipulating their environment, so are touch sensitive, and in toucans the beak also helps thermoregulate (control temperature).
But it’s not just birds. The platypus and echidna both have beaks, and the platypus beak even has electroreception too. If we look in the fossil record, there are extinct bird lineages that evolve beaks, many non-avian theropods (the meat eating dinosaurs), all the ornithischian dinosaurs (everything from duckbilled dinosaurs, to the horned ceratopsians), maybe a sauropod, some pterosaurs, some crocodyliforms, and some extinct mammal-like reptiles.
Why do all these groups evolve beaks? Why is a beak better than teeth? How does evolving a beak affect your skull function?
If you could know any one thing from the past for certain, what would it be?
Why did the non-bird dinosaurs die out at the end of the Cretaceous whilst many other reptiles survived.
Can you give us a brief overview of your current work?
My primary job is teaching anatomy to medical students as well as MSc students.
My research at present is a combination of projects including the evolution and locomotion of dinosaurs, feeding in dinosaurs, and felid/cat locomotion.
My MSc students are working on projects about hunting in Neanderthals, craniofacial reconstructions, and looking at shape variation and sexual differences in pelves of humans and chimps.
This is a periodical blog, probably monthly, featuring articles and interviews on topics I find interesting, and which inspire my writing.
Enjoy space opera?
The quest to unlock the secrets of interstellar travel leads a Roranian crew on an epic journey across space. Saved by a dying machine-lect, stranded in a failing ship, faced with an ultimate choice. Were they too eager in their attempts to reach the stars?