Or woman’s best friend...
The day my husband died, my Yorkie sat in my chair with me and would not leave me. That Yorkie lived 16 years.
Today, if I cry, the Yorkie I have now insists on licking the tears so that tends to make me quit crying. She is a guard dog, goes nuts barking if someone comes to the door.
The expression “man’s best friend” means “human’s best friend”, so it applies to both male and female.