According on the dimensions of a giraffe esophagus,

Southern giraffe drinking water

the researchers estimated that a full one can contain about 1.3 gallons. Additional computations revealed that each pump delivers around 10 ounces of water into the throat, and that a lengthy drinking session with 25-second intervals might require up to 17 pumping cycles. According to Binder and Taylor’s study, published in December in the journal The Physics Teacher, a parched giraffe would nearly fill its esophagus to the top.

“It’s a fantastic observation,” agreed Sunghwan Jung, a biophysicist at Virginia Tech who was not involved in the study. “But to determine for sure whether giraffes drink this way, they’ll need to employ X-rays to look inside their mouths.”