False pregnancy

Intact unspayed female rabbits (does) can undergo periodic false pregnancies, also known as pseudopregnancies. Pseudopregnancies mimic true pregnancies. However, they last only 16-18 days rather than 31-32 days of true pregnancy.

Symptoms
Below are symptoms of false pregnancies in rabbits.
 * Pulling fur from abdomen and chest.
 * Making a nest.
 * Developing mammary glands.
 * Aggressively defending nesting site.

Causes
Because rabbits ovulate in response to sexual stimulation by another rabbit, proximity of a male or mating behaviour between two females housed together can stimulate ovulation and result in pseudopregnancy.