the cheetah shows several specialized adaptations for prolonged chases to catch prey at some of the fastest speeds reached by land animals. Its light, streamlined body makes it well-suited to short, explosive bursts of speed, rapid acceleration, and an ability to execute extreme changes in direction while moving at high speed. The large nasal passages, accommodated well due to the smaller size of the canine teeth, ensure fast flow of sufficient air, and the enlarged heart and lungs allow the enrichment of blood with oxygen in a short time. This allows cheetahs to rapidly regain their stamina after a chase. During a typical chase, their respiratory rate increases from 60 to 150 breaths per minute. Moreover, the reduced viscosity of the blood at higher temperatures (common in frequently moving muscles) could ease blood flow and increase oxygen transport. While running, in addition to having good traction due to their semi-retractable claws, cheetahs use their tail as a rudder-like means of steering that enables them to make sharp turns, necessary to outflank antelopes which often change direction to escape during a chase. The protracted claws increase grip over the ground, while rough paw pads make the sprint more convenient over tough ground. The limbs of the cheetah are longer than what is typical for other cats its size; the thigh muscles are large, and the tibia and fibula are held close together making the lower legs less likely to rotate. This reduces the risk of losing balance during runs, but compromises the cat's ability to climb trees. The highly reduced clavicle is connected through ligaments to the scapula, whose pendulum-like motion increases the stride length and assists in shock absorption. The extension of the vertebral column can add as much as to the stride length. The cheetah resembles the smaller cats in cranial features, and in having a long and flexible spine, as opposed to the stiff and short one in other large felids. The roughly triangular skull has light, narrow bones and the sagittal crest is poorly developed, possibly to reduce weight and enhance speed. The mouth can not be opened as widely as in other cats given the shorter length of muscles between the jaw and the skull. A study suggested that the limited retraction of the cheetah's claws may result from the earlier truncation of the development of the middle phalanx bone in cheetahs. The cheetah has a