Are these litter mates?
How old were they when they were weaned from their mother?
Lynn
I don't know they were adopted from Petco.
Hi,
This is usually a behavior issue that is caused by the kitten being weaned too early from its mother. No, he's not getting any milk from the female kitten. What I would do is get some bitter apple spray, and put just a little bit on the female kitten so that if he tries to nurse it will taste bad. Grannick's is a good brand that I've used before. They actually have a new bottle with a dabber top made to put on cats. Here is a link to their website:
http://bitterapple.com/
If you have further questions let me know. If this answers your question please click accept. Thank you.
Veterinary Assistant
worked at a vet clinic for 15 yrs, BA in biology, have had cats most of my life