The rabbit may also be very aggressive and lunge at people who enter their territory to try to get any intruders to go away. Often times with rabbits, lunging is a warning. They don't want to hurt you, but they are letting you know they could if you don't back off. This behavior is almost always accompanied by a growl.
Hormones. Rabbits can display aggressive behaviour towards their owners or perhaps companions during the spring – the rabbits' natural breeding season. This aggression is hormonal and indicates a normal desire to defend their territory and ward off any rivals.
Rabbit aggression towards humans usually means they're scared. These fears can result in biting. A rabbit could also bite because they're poorly, or because their hormones are raging. Happy rabbits aren't generally aggressive but even the happiest bunnies may lunge, bite or give a sharp nip if they feel threatened.
The lunge. If your rabbit makes a sudden movement towards you with head and tail up and ears back, they are clearly telling you: 'I don't like that, back off'.
Hormones: Like moody human teenagers, a rabbit's bad attitude is often hormonally driven. Rabbits tend to be quite territorial by nature, and if your rabbit is still intact (not spayed or neutered), an intense desire to procreate makes aggressive behavior much more common and difficult to deal with.
Make sure they have a hiding spot or a different area they can move to, to be away from you. If you are cleaning and trying to remove their litter pan and your rabbit lunges at your hands, you can try to direct their attention to another area. Try presenting a snack or a toy on the opposite side of their space.
If they are sitting upright and their front paws are 'boxing' at you, they are likely very unhappy. Vocalising. Rabbits don't tend to make much noise and when they do it's a sign they're feeling very threatened. You may hear them grunting or growling and in extreme cases, they can scream.
Unspayed/unneutered rabbits tend to be much more aggressive. Unspayed females are particularly territorial, if they are going through a real or false pregnancy. Territorial behavior may include lunging, grunting, boxing, scratching, kicking and biting.
Signs of stress may include: appearing nervous (freezing, hunched up with ears flat against the body) being excessively jumpy and watchful (bulging eyes) being aggressive to people or other rabbits, particularly if the behaviour is unusual.
Acting Territorial
They may bite if they become worried you (or other bunnies) are about to take something away from them. This could be anything within your rabbit's territory including their cage, food bowl, litter box, water bottle or chew toys. Female rabbits will be very protective of their babies.
Lack of an interesting environment, opportunities to exercise, appropriate company and mental stimulation can lead rabbits to display abnormal behaviours including depression, fur plucking (self harming), aggression, chewing cage bars, altered feeding, drinking or toileting habits, sitting hunched, excessive hiding, ...
Their ears will lay back at a 45º angle and their tail will go up. Their nose will also usually be going very fast. If your rabbit is getting aggressive because they are scared, they might be leaning away from you, but if they are territorial, they may be leaning toward you.
In general, rabbits establish dominance using elaborate behavioral cues that include mounting, chasing, bowing, and grooming.
Petting a rabbit may be a great method to soothe them and help them relax. If your rabbit is defensive, scratch him behind the ears and forehead. Keep an eye on your rabbit's body language to see if he's still on the lookout for danger.
When your rabbit lays their head down flat on the ground, they are enjoying being pet and are laying still so that you continue. They might even close their eyes or nudge your hand if you stop petting them.
Growling/hissing/grunting
Your rabbit is angry, feels threatened and is showing disapproval. Your rabbit may, for example, be saying 'Leave me alone' if he doesn't want to be handled, or if he wants to protect his territory – such as his cage or food – from a human hand or another rabbit.
Usually this behavior is a result of past experiences that scared the rabbit. Your rabbit may have felt trapped or overwhelmed around people in the past, causing them to develop a phobia. As a result, your rabbit always runs away when you approach and is hesitant to spend time with you or bond with you.
Some bunnies are fine with being held, but never assume that your bunny likes being picked up just because they don't struggle in any way. Many rabbits hate being held and will actually freeze with fear. Our advise would be that it is always better to get down to your bunnies level and have a cuddle.
Boxing and lunging are aggressive behaviors. A rabbit will stand on their hind legs and punch with their front legs as if to “box” you or lunge at you. A rabbit may exhibit this behavior if they are frightened or uncomfortable with you entering their territory and touching their belongings.
In the wild, rabbits would spend their time digging, running, jumping, rearing up, hiding, eating, socialising with other rabbits (and being alone sometimes too). To allow your pet rabbits to carry out their natural behaviours they need to be given plenty to do.
Warning signs that something isn't right
Eating less and/or refusing certain foods. A change in thirst levels. Producing less stool or producing stool that looks different to normal. Discharge from the eyes or saliva around the mouth/chin.