Over half of the pregnancies are not successful. Rabbits are not particularly vocal, but if in acute danger or pain, can scream. Rabbits are not rodents, they belong to the order Lagomorpha. One of the differences from rodents is in the teeth. Lagomorphs have a second pair of upper incisors located right behind the first.
Rodents have only one pair of upper incisors.
The incisors grow throughout life so it is necessary to provide chewing material to keep the teeth properly worn down.