鯊魚屬於脊椎動物門軟骨綱(Chondrichthyes)板鰓亞綱，海生，少數種類進入淡水，為壹群遊速快的中大型海洋魚類。
Sharks are vertebrates steel door cartilage (Chondrichthyes) elasmobranchii, Marine, a few species enter fresh water, as a group of large Marine fish speed is fast.
鯊內骨骼完全由軟骨組成，常鈣化，但無任何真骨頭組織，外骨骼不很發達或退化，身體常被皮齒(質鱗)，牙多樣化，具有硬肌，但膜骨則永不存在，腦顱無縫。
Shark endoskeleton completely composed of cartilage, often calcified, but without any true bone tissue, degraded or exoskeletons is not very rich, the body is often skin teeth (scale), tooth diversification, with hard muscle, but never exist, membrane bone temple seamless.
上額由腭方軟骨組成，下額由梅氏軟骨組成。最新研究表明，鯊體內含有多種生物活性成分，如抗癌因子、角鯊烯、黏多糖等等。
On the forehead is composed of palatal side cartilage, the forehead is composed of Mr Medvedev cartilage.Sharks, according to new research in the body contains a variety of biological active ingredients, such as anti-cancer agent, squalene, mucopolysaccharides and so on.
擴展資料
鯊魚的起源不詳，但其地質學紀錄可追溯到泥盆紀(4.08億～3.6億年前）。鯊魚化石在中泥盆世出現，在石炭紀（3.6億～2.86億年前）成為占優勢的脊椎動物。現代鯊魚出現於侏羅紀早期（2.08億～1.87億年前），到白堊紀（1.44億～6,640萬年前）已經發展成現存的各科。
總之，除覓食和遊泳機制的改進外，進化對鯊魚的形態改變甚微。無論對化石種和現存種類來說，牙齒在鯊魚種類鑒別方面均有很重要作用。
百度百科-鯊魚