According to leftist fact checking sites, and the photographer himself:
Haim Zach, a press photographer for the Israeli government, took the photo. Zach told the AP in an email that Ravitz is an ultra-Orthodox Jew and when Biden reached out to shake her hand, Rivlin explained to Biden that she doesn’t shake hands with men, adding that she’s a mother of 12. Zach said Biden then knelt and told Ravitz that as a Catholic man he wanted to show his admiration to her as a mother of 12.
According to leftist fact checking sites, and the photographer himself:
I've never seen any mention of a dog before.
https://www.berkshireeagle.com/ap/factcheck/photo-shows-biden-kneeling-to-respect-israeli-president-s-aide/article_c08e0d68-e112-11eb-a645-77c62a1b22e5.html
Yes, I've heard that version of the story as well as claims Biden was tying his shoelaces and petting an invisible dog.
Catholics dogma dictates that Catholics never bow to anyone but God.
Also, if Biden was bowing to the woman, why the fuck was he facing the Israeli President?