Trauma is one of the leading causes of death in cats — with road traffic accident being responsible for 60% of those deaths — and is responsible for nearly half of deaths of cats under the age of 5 years (O'Neill et al, 2015). For this reason, or for the protection of local wildlife, or for other reasons, owners may choose to keep their cat indoors.
It is the responsibility of the owner or keeper to make sure that the indoor cat has the opportunity to fulfil normal behaviours, including access to appropriate sensory stimulations, such as interesting sounds and smells, and the opportunity to exhibit natural behaviours, including appropriate social interaction, choice of resting and hiding places, and the opportunity to engage in hunting behaviours. Owners should be educated about environmental enrichment to achieve these.
Cats should be provided with a range of resting and hiding places, including high-up sites from which they can survey their surroundings. Cardboard boxes make good cat hides.
For some cats, social interaction with humans appears to be sufficient, while others prefer another cat, particularly a littermate or other cat familiar since early kittenhood. Care must be taken if introducing another cat to one already resident, as this may be stressful.
Sound enrichment can be provided by opening windows so that the cat can hear outdoor sounds such as birds nearby. If few natural sounds are available locally, recorded natural sounds can be played for the cat.
Some scent enrichment can be provided simply by bringing clothes, shoes, bags etc. into the cat's home. Scent enrichment can also be provided deliberately, for example in the form of herbs. The most well-known is of course catnip, to which many cats will react ecstatically. Less well known is silver vine, which can provoke a similar reaction even in cats that fail to respond to catnip.
The natural behaviours associated with hunting — stalking, chasing and pouncing — can be encouraged in several ways. Small toys such as catnip-filled mice or scrunched up paper can be pounced on, thrown and caught by the cat. A similar toy or bunch of feathers, dangling from a string at the end of a pole and moved by a human, can be stalked, chased and pounced. Laser pointers can be chased, but never caught, making them less than ideal. Larger toys scented with catnip or silver vine mimic larger prey, encouraging holding, biting and raking with the hind feet.
Food-based enrichment is often overlooked but should be central. Rather than providing food in a bowl either constantly or a few times a day, the cat can be encouraged to hunt and work for its food. This may include placing food above ground level (e.g. on windowsills or tops of bookcases) so the cat has to jump up to reach the food; placing food in a variety of sites, so the cat has to walk around its territory to check for and find its food — some of which may be hidden; and using puzzle feeders.
Several puzzle feeders are commercially available, such as balls with holes in, which the cat has to roll around to make the food fall out; tubes with food at the bottom, so the cat has to fish the food out; feeders with pieces to be moved to access food; and systems where the cat has to knock food down from one level to another before eating the food at the bottom. The ‘NoBowl’ feeding system takes the hunting theme further: pieces of food are placed in several ‘mice’ (that can then be hidden); food falls out of the ‘mice’ when the cat plays with them, batting them around and catching them and throwing them as it would with live prey.
Enrichment devices can be made quite cheaply from items readily available in the home: 500 ml plastic drink bottles with holes cut in; boxes of various sizes with holes in the sides (and in the top, for larger boxes) for the cat to ‘fish’ pieces of food out; kitchen roll or toilet roll centres attached together giving a honeycomb structure so the cat has to look into the tubes, find which ones have food in and fish the pieces of food out. See http://foodpuzzlesforcats.com/forideas.
If they are to be used successfully, feeding devices should be introduced slowly, first using items from which the cat can get the food easily, and baiting them with treats initially to encourage their use, but eventually the cat can enjoy more challenging food retrieval and ‘hunting’ for most or all of its regular diet.
If all these strategies are used, in a manner appropriate to the individual cat, then the indoor life can be not only safe but also interesting for the cat.