Is it possible for my 4 1/2 month old Tonkinese kitten to be in heat already?!?!?

Crazy as it sounds it does actual sound like she is. Much like humans, so many things we eat can affect their harmones as well. I have heard of a 5 year old child starting her cycle, it had to be treated with medication from her physician so at this point anything is possible. It is too early definitely and if she were to become pregnant (heaven forbid) there would be a high percentage that the kittens and her would be in serious trouble. Get that spaying done as soon as possible because if she is and regardless if she is a indoor cat, they can be tricky and devious about how to get it.

Yes yourkitten is in heat. I have known kittens as young as 4 months to come on heat. The vet will not be able to desex her until she is 6 mths old. Whatever you do - don't let her out as she will mate and get pregnant. It really is too young for her to have a litter and if you choose to have a litter aborted and a desexing at the same time it will cost you 2-3 times as much as a standard desexing.

Male kittens don't tend to show any interest in mating so young.

You should never feel you have the right to kill. You should have them spayed/neutered or they will reproduce eventually. If you have dont the right thing for so long by keeping these kittens why do you not want it to continue? There are low cost spay/neuter programmes available- getting the boy done first would be best as this solves the immediate problem but of course the girls will go elsewhere for a mate sooner or later. I find it hard to understand how anybody would actually be able to feel they have more power than God and can pick & choose if an animal should live or die. It is beyond me. Please spay/neutrer them then you will have no more, and continue providing a good home to these babies.

Sounds like she's definitely in heat. I'd question that vet of yours. Cats can go into heat from 4 to 6 months of age.

She's in heat. It can happen any time around 5-6 months. Sounds like she's just an early bloomer. Might be because there's other cats around, it triggered her to start sooner.

Yes, your randy little puss is on heat. My little puss did the same thing at about 5 months, but they can do it earlier sometimes. She's just an early developer. Talk to another vet.

You may have a probem if one of your other cats is a boy, because they WILL do 'it' when he realises whats going on.

She may be a little older than you thought. She is showing signs of heat and should be spayed if that is your decision. The behaviour will get worse in the next couple of weeks. Weigh out your choices and have a purrfect year.

Maybe, but when you do get her spayed, if you do, make sure she stays confined for 5 days. We had our kitten spayed on Tuesday, and let her to her normal things because she wouldn't stay still. Well, she developed a HUGE bump so we took her to the vet today. They had to do emergency surgery and take care of it. We got her back today, but they gave us a cage to keep her in for 5 whole days. SHE IS CRYING and it is breaking my heart. I started crying, and my husband thinks i am overreating, but I can't help it. She is just a baby, (5 months) and does not understand why after all this time she is suddenly in a cage. (It is soooo sad) She keeps trying to climb the bars and get out.

She is probably in heat. My cat started going into heat when she was about 5 months old.

she might be on heat coz once when our kittens were about two months old (not old enough to be fixed) one of the male ones started trying to hump our little female