The Presentation of Our Lord & the Purification of Mary

Introit: We have thought of Thy lovingkindness, O God: in the midst of Thy temple.
according to Thy Name, O God, so is Thy praise unto the ends of the earth: Thy right hand is full of righteousness.
Ps: Great is the Lord, and greatly to be praised: in the city of our God, in the mountain of His holiness. Glory be to the Father,...

Gradual: We have thought of Thy lovingkindness, O God: in the midst of Thy temple.
according to Thy Name, O God, so is Thy praise unto the ends of the earth. As we have heard, so have we seen in the city of our God, in the mountain of His holiness. Halleluia. I will worship toward Thy holy Temple: and will praise Thy Name. Halleluia.

Offertory: Grace is poured into thy lips: therefore God hath blessed thee forever, and for ages of ages.

Question: How, then, did a groundhog come to have top billing on February 2?