Queen Aliens are significantly larger and stronger than the normal adults, being approximately 4.5 metres (15 ft) tall. Their body structure also differs, having two pairs of arms, one large and one small. The queen's head is larger than those of other adult Aliens and is protected by a large, flat crest, like a crown, which varies from queen to queen. Unlike other aliens, the queen's external mouth is separately segmented from the rest of her head, allowing her to turn her mouth left and right.