Orca dorsal fins collapse primarily due to their composition of fibrous connective tissue made of collagen, not bone, which requires the support of water pressure to remain upright. In the wild, orcas swim quickly in deep water, which keeps their dorsal fins healthy and straight. However, in captivity, orcas spend much more time at the surface and swim in confined spaces, which leads to a lack of water pressure to support the fin. This loss of support, combined with factors like reduced swimming activity, stress, diet changes, and exposure to warmer air temperatures, causes the dorsal fin to partially or completely collapse. Collapsed dorsal fins are far more common in captive male orcas (100% of adult males in captivity) than in wild populations, where less than 1% of males typically have collapsed fins. In the wild, collapse is usually caused by injury or environmental stress but is rare overall. The fin collapse in captivity is considered a structural, irreversible change in the collagen due to altered conditions like less activity and more surface time. Thus, the main reasons for orca dorsal fin collapse are lack of water pressure support and physiological changes in the collagen structure due to captivity conditions such as confinement, inactivity, and thermal effects.