Socialisation in dogs and cats
Socialisation is a term usually used to describe a period of learning (up to 14- 16 weeks old) that puppies go through. During this period they learn how to properly interact with other animals and humans as well as experiencing different situations, objects and environments. Dogs that have not been properly socialised during this period can grow up to be fearful, anxious and potentially aggressive. During this socialisation period there is also a fear imprint period (also known as a sensitive period) and any negative or scary experiences during this time can have a lasting effect on the puppy. Interestingly, the age of onset of this period is different between breeds, with Labradors not starting the fear imprint period until 72 days old compared to German Shepherds at 39 days old. This could explain differences between breeds and their ability to deal with new situations or environments when older.
A socialisation period has also been discovered in kittens but is thought to be between 2-7 weeks old. This means that the breeder or rescue centre will have the sole responsibility of ensuring the kitten is exposed to as many new stimuli as possible during this period to ensure they make friendly, confident pets before they go to their new home.
Socialisation in rabbits
What about rabbits? There is a wealth of information about puppies and socialisation, a little about cats and even less about rabbits, however if we are to try and prevent the large number of rabbits being given up to rescue centres this is something that we should be focusing on. A properly socialised baby rabbit, that is used to humans handling them is much more likely to go on to become a more relaxed and friendly pet. According to Dr. Dyles (2006) the socialisation period in rabbits is between 10-21 days old and to ensure baby bunnies grow into tame, friendly and confident adults they must be handled before they are 21 days old (but it is also important for handling to continue regularly after this age). This means that breeders (and rescue centre staff) have the responsibility of making sure the rabbits they sell or put up for adoption are accustomed to being picked up and handled. If you are considering getting a rabbit from a breeder this is something you should ask – how much handling have they had? Along with what are the temperaments of the parents? Are they placid, friendly parents? Ask to meet them to see for yourself.
Baby bunnies that have not been handled when young are more likely to fear humans and may grow into timid, frightened adults. This fear can escalate into aggression, especially if they learn that biting or lunging makes the scary thing (perhaps a human hand) go away. Behaviours like this are just one reason rabbits become neglected or given to a rescue centre. Preventing this scenario from happening in the first place is the best option.

Photo credit – Thanks to Jayne Bethan Townsend; Friends of Animals Wales.
Habituation in rabbits
If, however you already have an adult rabbit that is fearful or aggressive (which is usually due to fear) it is still possible that they may be taught to become less anxious. This is usually through the process habituation. Habituation occurs when the rabbit is exposed to the stimulus enough times that it eventually gets used to it and stops reacting. For example, with enough time and patience, a rabbit that shrinks away every time you put your hand towards may start to realise that nothing bad is going to happen and instead of shrinking away they may stay still, eventually they may even let you stroke them and finally may offer their head for stroking. For this to work, an owner must be patient and move slowly so as not to startle the rabbit. This process may take weeks, months or longer and all interactions should be made as positive as possible, using a tasty treat may help or you may find that speaking to them calmly and quietly helps. If you proceed too fast it could scare the rabbit and make matters worse.
If you have an aggressive rabbit the Rabbit Welfare Association and Fund have a great leaflet called Biting the Hand that Feeds. However, if more people are made aware that rabbits, like dogs, also have a socialisation ‘window’ this may help to prevent behavioural problems later in life – resulting in happier rabbits and owners.

Photo credit – Thanks to Jayne Bethan Townsend; Friends of Animals Wales.
References:
Breeding pet rabbits health & welfare considerations: / Dr. L. Dyles. .
Different dog breeds, different sensitive period: 2015
COAPE: Critical Periods (Sensitive Periods) in Puppies – Revisited 2015
Nicky Trevorrow (2012) Kitten Socialisation: The Cat, Summer 2012. p46-47