Ahead of the premiere of T. rex Autopsy on the National Geographic Channel, palaeobiologist Dr. Tori Herridge spoke to us about her involvement in the documentary, along with her research topic and her thoughts on cloning.
The documentary airs at 8pm on Sunday 7th of June, and kicks off a week of dinosaur programming that includes Dino Death Match, T. rex: Ultimate Survivor, Bigger Than T. rex and a two hour special entitled Top 10 Biggest Beasts Ever.
The documentary combines biology with paleontology to explore the guts and glory of a T. Rex, re-created using state-of-the-art special effects and cutting-edge science.
Can you tell me a bit about your background and what sparked your interest in palaeobiology?
Sure, I’m primarily a paleobiologist, and a researcher at the Natural History Museum. My research focus is understanding how evolution works by looking at the dwarf elephants that evolved on islands in the Mediterranean during the Ice Age. These elephants were tiny, measuring only one metre tall, but their ancestors were even bigger than the African elephant, which still walks the Earth today. I use this to try and understand evolution better as a whole. My interest in palaeobiology goes back to when I studied human evolution and archaeology, and bit by bit I rolled further back in time, becoming fascinated with the Ice Age and everything that lived there. This eventually led me to the dwarf elephants I still study now.
What were the challenges associated with carrying out the autopsy?
Size! We were dealing with a creature measuring over 40 foot, not the mention the girth of the T. rex and the size of its legs. To make any sort of dent into it we needed very large surgical knives. When we went to take the leg off there was no way a knife could do it, so Luke Gamble, the veterinary surgeon who led the autopsy, had to get out a chainsaw! Physically cutting through such a large model was incredibly tough, the designers of the T. rex had to think in three dimensions, particularly about where we were going to make our cuts. When Luke was doing the major cutting, there was a lot of time when he was stood inside the abdomen of the T. rex , he was almost swimming in the amount of prosthetic blood inside it!
Personally, I was given the task of investigating the T. rex’s cloaca. Mammals like us that have placentas are quite unusual as they have separate openings for our urine and our faeces and quite often a separate opening for our reproductive organs. So basically there are two or three holes where things come out. In most other animals they just have a single opening called the cloaca, where all those different substances come out of the same place. When we were trying to investigate the sex of the T. rex, the only way to do that was to get right inside the cloaca. While a lot of birds today don’t have penises, those that do are thought to be the most primitive, at the bottom of the bird family tree and therefore might be the most dinosaur-like. Even their penises are often tucked inside the cloaca, so the only way to find that out was to get my arm up inside it, and I actually got stuck!
Can you tell us the major findings from the autopsy?
The whole point of the autopsy was to try and uncover the life story of the T. rex, and also how it died. The point of that was to try and allow people to think of the T. rex as a living creature in the environment rather than just a fearsome beast that’s just a skeleton in a museum collection. In that sense, the discoveries we made were personal to this individual T. rex model, which then told a broader story of what dinosaur life was like.
One of the key things that sticks in my mind that was really fascinating was when we took the heart out. Although we don’t have any fossilised T. rex hearts to look at, the inspiration for its design was taken from fossil evidence. As birds are thought to be the closest living thing to a dinosaur, they used the structure of a bird’s heart as a basis for the T. rex’s heart. Of course there are currently no birds anywhere near the size of a T. rex, so they had to scale up the heart dramatically. There’s a general rule across animals and birds that the heart is on average 1% of the animal’s mass. Using that as the guiding principal, they built the T. rex heart, but found that it was too big to fit inside skeleton. This immediately told them that it had to be smaller than the standard 1%. That’s quite interesting as it suggests that the T. rex was at the lower end of this scale, although we can never prove this without a real T. rex heart! What this does clearly show however is the importance of going beyond the fossil record.
There were also some nasty surprises that the team who built the T. rex were behind. They’d cunningly filled up the large intestines with excrement filled with worms, indicating that the T. rex had a parasitic infection. This makes a really interesting point, which is that although we are focusing on dinosaurs they weren’t alone on our planet. There was a host of much tinier animals, and even smaller organisms such as parasites. That’s a whole ecosystem that we often forget about when we think about the past.
You filmed a documentary that was broadcast last year on the autopsy of a woolly mammoth. Have there been any developments since it was filmed?
The Korean team were waiting for a while to receive their material, and so far they haven’t found a complete cell from the mammoth tissue. The DNA they’ve found has also been quite fragmented and poorly preserved, with only short sequences in tact. The other scientists are likely to be still waiting for their tissue samples due to the difficulties in importing substances such as mammoth tissue.
Could you tell me about your viewpoint on cloning? What’s the likelihood of seeing an extinct species return to our planet via this process?
It varies depending on the animal. In the case of the mammoth, you’re never going to produce one solely by cloning. The closest you might get is an elephant that has had its DNA tweaked to bring out some features that make it look more like a mammoth. But even for this to happen, it would require a lot of experimentation on living elephants, and that in itself is an ethical problem which I hope people would be stopped by. This is also a huge practical challenge, as you would need to keep an awful lot of elephants in captivity and happy enough to carry a foetus to term. All these problems are tough enough with normal elephants, let alone with a genetically different organism. Based on this, the likelihood of it happening is very low, and from a personal viewpoint I don’t think it should be done.
So the money would be spent preserving the animal species that currently populate the Earth, rather than trying to bring back an extinct species?
People make the argument that these aren’t the same pots of money. This may be true, but I would make the argument that they actually should be, why do people find bringing back the woolly mammoth more exciting than saving what we’ve already got? It would be more of a travesty for our generation to be the last to see certain species alive today than for the woolly mammoth to remain extinct, even if it were possible to bring them back.
If you want to learn more about the T. rex and all of the other dinosaurs, make sure you pick up a copy of Issue 73 of How It Works, which features 101 gigantic facts about dinosaurs! It’s available to order in print, and you can also download the digital version or subscribe today to ensure you never miss an issue!