Yemenite Jews did not have sheep or goats, so they used the horn of an antelope. Most animal horns can be used, except for the cow, which is reminiscent of the golden calf.
“When they make a long blast with the ram’s horn, as soon as you hear the sound of the trumpet, then all the people shall shout with a great shout; and the wall of the city [Jericho] will fall down flat, and all the people shall charge straight ahead.”
Scripture tells us that a ram was caught in the thicket at Mount Moriah and sacrificed instead of Isaac. (Genesis 22:13) The first blowing of the shofar was when God called the people to worship at Mount Sinai. The first shofars would have been ram’s horns, which were available only after the death of the animal.
The shofar is blown in synagogues today during the high holy days of Rosh HaShana celebrating the Jewish New Year. Ten days later, the Yom Kippur (Day of Atonement) worship service ends with a mighty blast of the shofar.