Water is considered to be the source of life. It is important for animal life because of the following reasons:
(i) Water is vital body fluid which is essential for regulating the processes such as , digestion , transport of nutrients and excretion. Water dissolves ionic and large number of polar organic compounds. Thus, it transports the products of digestion to the place of requirement of the body.
(ii) Water regulates the body temperature by the process of sweating and evaporation.
(iii) Water is a medium for all metabolic reactions in the body. All metabolic reactions in the body take place in solution phase.
(iv) Water provides habitat for various animals in the form of ponds and rivers, sea, etc.