Complete Passuk
וַיֹּ֩אמֶר֩ יְהֹוָ֨ה אֱלֹהִ֥ים ׀ אֶֽל־הַנָּחָשׁ֮ כִּ֣י עָשִׂ֣יתָ זֹּאת֒ אָר֤וּר אַתָּה֙ מִכָּל־הַבְּהֵמָ֔ה וּמִכֹּ֖ל חַיַּ֣ת הַשָּׂדֶ֑ה עַל־גְּחֹנְךָ֣ תֵלֵ֔ךְ וְעָפָ֥ר תֹּאכַ֖ל כָּל־יְמֵ֥י חַיֶּֽיךָ׃
Chabad / Judaica Press
Chazal
Chazalתַּנְיָא, מִפְּנֵי מָה הַנָּחָשׁ מְשַׁמֵּשׁ פָּנִים כְּנֶגֶד פָּנִים? מִפְּנֵי שֶׁדִּבְּרָה שְׁכִינָה עִמּוֹ, דִּכְתִיב וַיֹּאמֶר ה׳ אֱלֹהִים אֶל הַנָּחָשׁ.
It was taught: Why does the serpent mate face to face? Because the Shechinah spoke with it, as it is written “And the Lord God said to the serpent.”
On the daf / in context: The direct address of the Shechinah to the serpent is given as the reason for its unique mating posture among animals.
Type of Learning: Custom (reason for serpent’s mating posture)
What Is Learned: Because God spoke directly to the serpent, it mates face to face.