Its skin can typically range from a blue or green hue to light with a white or light yellow underbelly. The distinguishing dark spots and stripes are most outstanding in young sharks and fade as the shark matures. Specimens regularly weigh 385 to 635 kg (850 to 1400 lbs). It is usually 3 metres (10 ft) to 6 metres (20 ft) long. The heaviest specimen recorded to date, a shark caught in Newcastle, NSW, Australia in 1954 and measuring a mere 5.5 metres (18 ft), scaled 1,524 kg (3,360 lb). Sexual maturity is reached at different stages for each of the sexes; males at 2.26 metres (7 ft) to 2.9 metres (10 ft) whereas females mature at 2.5 metres (8 ft) to 3.25 metres (11 ft). It has been estimated that the tiger shark can swim at a maximum speed of around 32 kilometres per hour (20 mi/h), with short bursts of higher speeds that last only a few seconds. Tiger shark swimming below tubing visitors in acrylic tunnel at Atlantis.The tiger shark`s head is somewhat wedge-shaped, which makes it easy for the shark to turn quickly to one side. Tiger sharks, as with other sharks, have small pits on the side of their upper bodies which hold electrical sensors called the ampullae of lorenzini, enabling them to detect small muscle movements of other creatures, allowing them to hunt in darkness. In addition, the tiger shark, like many other sharks, has a mirror-like covering behind their retina called the tapidum lucidum that is exposed in darkness to reflect light that has already been seen by the retina back at it as to allow the shark to see better. The tapidum lucidum is covered in bright light, however, as so the shark is not blinded by an excess of light. A tiger shark generally has long fins and a long upper tail; the long fins act like wings and provide lift as the shark maneuvers through water, whereas the long tail provides bursts of speed. A tiger shark normally swims using lithe movements of its body. Its high back and dorsal fin act as a pivot, allowing it to spin quickly on its alliance. Its teeth are flat, triangular, notched and serrated. Like most sharks, when a tiger shark loses or breaks one of its teeth, it grows a replacement tooth. The distinctive teeth are able to cut through turtle shells, and an adult tiger shark can easily bite through bone.