Do actors prephere to play humans or other things (such as animals, robots, trains etc) when on stage?
— Johan The Cat (@RhaspJM) April 2, 2019 
Well, every actor prepares for a role using many different methods – but some prepare more than others. While one actor’s preparation may involve learning lines, another’s may involve years of character study – eating as the character, dressing like the character, living like the character and procreating like the character (classical actors are masters at this, dear).
All these different methods are taught at drama school, where actors have terms devoted to animal studies, tree studies, and Cameron Mackintosh studies. These important disciplines help an actor develop a toolbox of techniques they can whip out anytime David Grindrod – or another casting director – demands they impress him.
Animal Studies involves finding an animal you think resembles the character you’re playing. You then study how the character moves, eats and shits – and utilise it in your character development. For example, you may feel like your character is rather bullish – in which case you spend a week in a farmer’s field stalking a bull. Or you may think your character is a lazy, stoned hippy – in which case you take a flight to South America and hang out with a sloth.
It’s interesting that you mention robots. These are to be avoided at all costs – unless it’s a production of Terminator: The Musical. I’ve seen numerous performances where actors appeared to have studied a robot, when in fact they hadn’t – they were just stiff and wooden.
Trains and other vehicles can be excellent choices for character study – who can forget the performances in Starlight Express, National Express and the Queen Elizabeth Line Express (where the actors studied tortoises, dear).
Many companies employ movement directors, who work with actors to prepare them physically, and ‘release’ their bodies. These experts help actors recognise their own patterns of behaviour and develop new habits. Every actor will naturally move in their own way – and the key to finding a new character is through finding a different physicality. There have been many celebrated performances from actors in the past who explored their character’s physical capabilities – Antony Sher in Richard III (like a spider nimbly pulling himself around stage on sticks), Mark Rylance’s remarkable physical re-invention as Rooster in Jerusalem, and Elaine Paige’s turn as a feline (the secret to playing a cat – dress up in fur and say “meow”, dear).
Some companies such as DV8, Frantic Assembly, Temper Theatre, Gecko and Trestle Theatre specialise in physical theatre. These companies use physicality to tell a story – and are always thrilling to watch. Many performers in these companies come from a dance background – usually this means they have a better expression and understanding of their bodies. If you get the chance, I recommend seeing their work and keep an eye on their websites as they sometimes offer workshops where you can learn about these different methods of performance preparation. Then you too can prepare to play an animal, robot or