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, and infertile mating, or mating behavior between two females housed together can stimulate ovulation and result in pseudopregnancy. However, it can also be observed in female rabbits with no contact with other rabbits.