Spring fever in pet rabbits and what does it mean for rabbit owners?

Hormonal behaviours are still present in neutered rabbits as it does not rid them of their main hormone, testosterone for males and oestrogen for females. Not all sex hormones are produced by the ovaries and testes, so even when these are removed, the adrenal gland will continue to produce some sex hormones.
Hormonal behaviours are commonly seen in neutered rabbits, especially during the spring. Social, sexual and aggressive behaviours occur more frequently during the spring because of the hormonal drive, as spring is the peak breeding time for rabbits in the wild, so hormones are massively heightened at this time. Females may dig out new burrows or rabbits may be aggressive to other rabbits or people. This includes chasing, mounting, nipping and biting. In some cases, you may need to separate a bonded pair because of this aggression. There also may be an increase in chinning behaviour to mark their territory.
Some rabbits will show more sexual behaviour than others. This appears to be because the adrenal glands produce more testosterone in some rabbits than others. Neutered rabbits also have higher levels of sex hormones than neutered animals of other species, which suggests that the adrenal gland produces a substantial amount of sex hormones in rabbits.
Hormonal behaviours will start to increase when the days get longer, and it starts to get warmer, so it is important to keep an eye on your rabbit’s behaviour during this time, especially if they are bonded with another rabbit.