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Conclusion

In conclusion, Bowheads have adapted several physiological, morphological and behavioural mechanisms to successfully inhabit this extreme cold habitat. They have developed a long-life span to accumulate sufficient growth and blubber as well as having genetic alterations to support their survival.  Bowhead thermoregulatory adaptations are key in this cold climate to maintain their body temperature at 33.8°C. The adaptations for heat conservation are large body mass, thick blubber insulation, countercurrent heat exchange system in fins, flukes and the tongue. Heat dispersal adaptations are AVAs circulatory system and corpus cavernosum maxillaris (CCM).Bowheads also adapted an ideal morphology and behaviour that allows them to break through thick ice or locate areas of open water and thin ice cover for breathing holes. Bowheads adapted thick skin bow-shaped heads (break through thick ice without sustaining any physical damage) and eyes that have a tapetum (adapted to see in the dark and detect light intensity); use acoustics for echo location which allows them to distinguish between ice thickness. Bowhead longevity ability has resulted in late sexual maturity and an adaptation in the reproduction cycle (behavioural, gestation and lactation length and timing) which increases the species survival success. With increased gestation and lactation periods new-borns have a relatively thick blubber layer and rotund body form, this and the selective growth strategies has better equipped calves to survive in the cold environment. Bowheads are efficient filter feeders and obtain high density of lipid rick zooplankton using their morphological adaptation. To detect dense population of prey they have retained the olfactory bulbs in the brain (sense of smell in air), this allows them to smell the potent odour produced by krill.  During hunting (filtering) the Bowheads oral cavity results in feeding being powered by hydraulic and hydrodynamic pressures, these forces prevent prey from escaping. Therefore, Bowheads are highly adapted and the most efficient filter feeder predictor in the Arctic Ocean (coldest northern hemisphere habitat).

 

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