why animals living in colder climates tend to have more poly

why animals living in colder climates tend to have more polyunsaturated fatty acids in their fats than animals living in warmer climates

Solution

Lower transition temperature (melting temperature) of polyunsaturated fatty acids prevents the fat from solidifying in colder climates.The longer the chain length the higher the melting point.The degree of unsaturation lowers the melting point as a result of reduced van der Waals interactions (more double bonds the lower the melting point).Prevention of solidification helps them to use the fat for insulation purpose.