June 21 is the longest day only for the northern hemisphere. The southern hemisphere would therefore celebrate giraffes on the (or about) the 21st Dec. Also,

June 21 is the longest day only for the northern hemisphere. The southern hemisphere would therefore celebrate giraffes on the (or about) the 21st Dec. Also, from a cursory search, giraffes occur both north and south of the equator in Africa. So neither northern or southern hemisphere could lay sole claim to picking a day.