They don't bite, they don't make a mess on the carpet and they don't cost anything to feed. The appeal of virtual animals is clear. Both cute and attentive, they treat you as if you are the centre of their world – without any vet's fees. Video games involving animals are perfect family fun, and come in many forms. Virtual pets have been particularly popular – over 70 million Tamagotchi toys, the Japanese handheld digital pet, have been sold, while the Nintendogs series, in which the player looks after a virtual puppy on their DS, has been a major seller for Nintendo since its launch in 2005.
Other beastly adventures have involved giving players the chance to run a zoo – the Zoo Tycoon titles – or shape the lives of wild animals, such as the SimAnimals franchise. For the developers, they pose a unique challenge – given that these games live and die on the appeal of their stars, recreating nature can be a tough job.
On Friday animal fans will get the chance to play the latest in a litter of new animal-inspired titles. World of Zoo, available on the DS, PC and Wii, lets gamers get closer to the animals and more involved in their lives than is possible in real life. For the game, US developer Blue Fang – the company behind the Zoo Tycoon titles which first went on sale in 2001 – had its work cut out, creating more than 90 species across 11 animal "families", with one of the first tasks being to decide how realistic the creatures would be.
"We really wanted World of Zoo to be a fun, high-paced game," says Steve Gargolinski, who worked on the animals' AI (artificial intelligence). "However, one thing that we learned during our trips to the zoo is that real animals often do a lot of lying around."
To deal with this issue, some leaps of imagination had to be made. "We needed certain animals to do things that they never do in the wild," says Gargolinski. "Giraffes don't roll over – but we thought it would be fun for them to do it. So our animators sat down with the challenge of answering the question, 'If giraffes did roll over, what would it look like?'"
The result, Gargolinski hopes, is believable, if not realistic – something that was the aim of the game. One of the key figures in attempting this goal is Bruce Blumberg, an expert in animal learning and behaviour. Not only does Blumberg have a wealth of academic experience – he is former professor at the Massachusetts Institute of Technology (MIT) Media Lab and currently teaches at the Harvard University Extension School – he is also a keen dog owner who competes in shows with his Border Terrier, Scuppers.
Since animal games are all about keeping the creatures happy, players need to be able to tell how they are feeling – a challenge for Blumberg, who worked on how this could be communicated through the animals' animation. "One of the first things I did was take videos of me with my dog, doing things like holding up a bone or pretending I was going to throw a ball," says Blumberg. "Then we would analyse it frame-by-frame – it would get people thinking about the conversation that is going on and how we know what the animal's thinking."
Blumberg was also able to take his academic background and use it in the game's development. "One of the projects I did at MIT was a dog-training simulation," he says. "That's something that probably wouldn't make a great game, but it was a really good intellectual exercise, and it contained many of the same ideas that carried over to World of Zoo in terms of really paying attention to what the animals were telling the player."
In World of Zoo the animals are split into enclosures, so only interact with members of their own animal "family". The team behind SimAnimals, however, had a different challenge. The series of games – the second of which, SimAnimals: Africa, was released last week – are set in the wild, meaning developer Electronic Arts has had to work out how the animals would react with each other.
By studying animals' natural behaviour – what they eat, whether they hunt or are hunted – its creators came up with what Sam Player, executive producer, calls "a recipe for each animal for how they'll behave". The results, he says, are animals with their own realistic behaviour patterns.
"The game is a living, breathing eco-system," says Player. "If you want to sit back and watch it like it was a terrarium, you could, and the animals would take care of their own needs." Still, like World of Zoo, some changes to reality had to be made. "If we went with super-realism with our animals, we would basically have a game where they sleep, eat and try to kill each other," says Player. Of course, getting the virtual animals' behaviour spot-on is useless if poor animation reminds the player that they are just a bunch of pixels. Interestingly, Blue Fang did not attempt photo-realistic graphics for World of Zoo, instead using cel-shaded animation, and the resulting cartoonish look, claims Blumberg, helps to involve the player in the animals.
"I think our animals, even though they may be less realistic than some games', are more believable and have more organic credibility because the movement really works," he says. "We focused on animations that tell a story to the player. We want them to roll over in a way that is communicating whether they are sad or happy."
Of course, basic visuals did not stop the Tamagotchi becoming a craze, but now the virtual pet concept has moved on with EyePet, an innovative game that places the pet in the room with you. It works by using a webcam to produce a live video feed of you in your living room, on to which the pet is superimposed, and the player can then interact with the critter using hand gestures.
When it came to designing the pet itself, the developers had to create something that would be able to fulfil all the activities they were including in the game. "We wanted to make our pet believable and something that people would be able to relate to, but our pet also has some special things that it can do," says Russell Harding, the producer of the game. "Rather than being a mythical creature, we wanted something that was still very animalistic, so that people would know how to respond to it, but can also draw and sing, which is not totally animalistic behaviour."
As a result, they created a pet that is like a cross between a monkey, a puppy and a kitten, although with human facial expressions because, says Harding, they wanted it to be expressive and avoid "text and voice-overs popping up". All these are features that help create a relationship between the player and the animal, something developers have to be careful not to ruin – Gargolinski believes the most challenging part of creating animals for World of Zoo "was never breaking the illusion of life that we worked so hard to develop".
He adds: "Let's say that a player has created a bond and shared a story with their absolute favourite baby tiger. If this tiger walks into a wall, freezes, pops through an animation, or looks stupid in any way, it causes huge damage to the player-tiger relationship. Suddenly that tiger is just buggy software instead of the player's real friend."
Whether an animated creature in a game can inspire the same depth of feeling as a living, breathing organism is debatable, but they do offer unique experiences that just are not feasible in reality. And of course, a break from those vet's fees.
Pet projects: Games to get your paws on
Ecco the Dolphin (Sega Mega Drive, 1992)
This classic side-scroller from Sega saw players take control of the eponymous dolphin, solving puzzles and attempting to save Ecco's pod. The game had an ecological theme and also represented dolphin dehaviour in a realistic way – it seemed to work, as the most recent Ecco title was released for Xbox Live Arcade in 2007.
Nintendogs (DS, 2005)
Nintendo's virtual pet dog title was set apart from the cyber-pet competition by the way it made use of the DS's features, such as being able to give orders using the microphone, stroke the on-screen hounds using the console's touch screen and because of the different versions which offer the chance to look after a range of breeds.
Viva Pinata (Xbox 360, 2006)
While Microsoft's Viva Pinata might have seemed to be all about candy-filled papier mache animals, it also encouraged players to create a haven for their menageries, keep their creatures safe and even encourage them to procreate.
National Geographic: Panda (DS, 2008)
Last year the National Geographic Society branched out into video games, and this panda simulation aims to educate as well as entertain.
Farmville (Facebook, 2009)
This free title gives social networkers the chance to build up a functioning farm, complete with interacting animals, while they work out who to poke; there are 62.8 million smallholders.