Abu Bakr bin Abi Dawud (may Allah have mercy on him) said: I heard my father, explaining the meaning of the saying of the Prophet (peace and blessings be upon him), "On the Day of Resurrection the muezzins will have long necks," say: It does not mean that their necks will be long. Rather, it is that on the Day of Resurrection people will be thirsty, and when a person is thirsty his neck folds over, but the muezzins will not be thirsty, so their necks will remain upright.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2037