Why does a killer whales fin bend over in captivity?
Most male captive Orcas, and some females, have collapsed (droopy) dorsal fins. Several theories exist as to why this happens. A dorsal fin is held erect by collagen, or compressed lipid cells. The collagen normally hardens in late adolescence. One theory is that in deep ocean waters, the pressure the water exerts on the fin allows it to remain supported while the collagen hardens. In captivity, however, shallow tanks lack sufficient water pressure to produce this effect, and the fin collapses before the collagen solidifies. According to another theory, the Orca is almost always in a state of turning in a tank, since it is not large enough to allow swimming in one direction for any normal duration. The constant turning exerts pressure on the dorsal fin, which in turn causes it to collapse. Other possible explanations include alterations in water balance caused by the stresses of captivity or dietary changes, lowered blood pressure due to reduced activity patterns, or overheating of the
