Assuming we are discussing the process of drinking and swallowing water rather than food, it takes quite a length of time for a giraffe to drink water due to its highly unusual drinking mechanism. Using its jaw as a plunger pump, with each pumping action taking about 1.5 seconds, the giraffe fills its esophagus after about 17 pumps (25 seconds) for a total volume of 5 litres (bit.ly/giraffe_drinking). After this drinking episode, the water is still estimated to be in the giraffe’s esophagus (about 1m down) when it lifts its head; hence additional time is needed to travel down the second metre of the giraffe’s throat by peristalsis (4cm/s) aided by gravity, perhaps less than another 25 seconds. I would estimate between 35-45 seconds in total, for filling its mouth and half its throat and then transporting the water to its stomach, completing the full action of drinking and swallowing water.
