Alexandra Freeman

A big and specialised series like Walking with Beasts takes a lot of research! I worked with researcher Paul Chambers full time for nearly two years. His degree in geology and doctorate in palaeontology and mine in zoology and animal behaviour (especially my undergraduate project work on fossils, click here for details), meant that between us we had the ideal background for the job.

Our first job was to decide where and when each of the six episodes was going to be set, and which animals we could portray. There were some animals which the producers (Tim Haines and Jasper James) had already decided had to be included, such as the sabre-tooth cat Smilodon, the woolly mammoth, the largest land mammal ever: the indricothere, and the early hominids, Australopithecus. Then we started to look for fossil sites which were particularly well preserved and gave us a real insight into life at one point in time. It was a real wrench to have to limit ourselves to just six time periods - if only we could have had one more and featured the mammals of Australia, which is probably the biggest ommission of the series.

The budget allowed us to reconstruct four or five animals for each episode, and we soon started to talk to experts and read academic papers about the animals which were around, and sat down with the producers to choose which were going to be the stars and costars of each episode. Assistant producer Annie Bates also started researching the environment for each episode. She had the difficult task of finding places around the world which could pass for the world many millions of years ago! Of course grass was the biggest problem, because it hadn't really taken off and formed plains until the fourth episode of the series, and yet open spaces with no grass are very difficult to find in today's world.

As soon as we had all decided on each animal, our first task was to start working with two specialist model-makers - Jeremy Hunt and Nigel Booth - to reconstruct accurate models them. This meant collecting accurate drawings and photographs of the reconstructed skeletons of the animals, and any other evidence that might help them flesh them out. Then, at each stage of the model-building we sent digital photographs round the world to experts who could help us make the models as accurate as possible. There is a page on the process on the first half of this page on the Beasts website.

We also had to work with the producers early on to help put together a storyline for each episode. The fossils often provided clues to aspects of the animals' behaviour, such as how they mated, how they hunted etc. Putting these together helped form the basis of each episode. Then there were the inevitable gaps, and I had to use my background in animal behaviour to make the best educated guess possible to fill these in.

Once the models were completed and cast in resin, they were taken to the computer animators in a company called Framestore where they were scanned in in 3D. Framestore have an excellent website here which gives full details of the entire animation process. In the meantime, I worked with the skin designers, Daren Horley and Martin Macrae at Framestore, along with the producers, to come up with reasonable skin colours and patterns for each beast. Occasionally there was good evidence for the type or colour of the fur, but often it was a matter of using general principles to come up with something.

The skin designs and the models together went to a company in Aylesbury called Crawley Creatures which made the animatronic models - scale or lifesize 'puppets' with real hair and moving parts. These are really useful for close up shots, especially with hairy animals because hair is extremely difficult to generate convincingly in the computer. We worked closely with Crawley Creatures to make the animatronics as accurate and lifelike as possible. There is a pageon the animatronics process on the Beasts website here.

Finally, I had to work with the animators to get the movement of the animals as correct as possible. Firstly I searched the archives of the Natural History Unit to find examples of animals moving and performing behaviours which would be useful to them as reference. Once they had 'walk cycles' and 'run cycles' for the animals, then we called upon the expertise of Professor McNeill Alexander from Leeds University who is an expert in biomechanics. He helped the animators calculate stride lengths and the capabilities of each animal. Occasionally we were faced with particular challenges, such as the amphibious Ambulocetus and the bipedal Australopithecus, where we took advice from many experts, sending little video clips by e-mail around the world!

We found that extinct mammals were much less studied than dinosaurs, which meant than rather having to make a choice from a range of different opinions on one dinosaur, we often found mammals which had hardly been studied since their discovery, a hundred years before! Having pulled together the information for the series from about 450 different experts, we were very keen to make this pool of knowledge as available as possible to the public, whose interest we hoped would be stimulated by the series. Two 'Science Of' programmes had been commissioned to run on BBC1 alongside the main series,and so we worked with producer Kate Bartlett and researcher Lucy Bailey to help put those together. However,I was particularly keen to use my experience to produce an extensive website, especially incorporating fun and educational material for children. In addition, executive producer Tim Haines started investigating the possibility of using digital technology to produce an interactive television version, and I quickly became involved in this as well.