Why do my male hamsters look like they're mating? Is it aggression?

Hello. Unneutered male hamsters will try to mate with other males if females are not around. Also, they are more likely to fight because they are unneutered. You can try getting them neutered in order to change the behaviour. Otherwise, you may have to separate them if they start fighting. I would suggest having them seen by your vet to discuss neutering. Best of luck with your little ones!

thanks for reaching out about Coco and including a photo. this is likely bite wounds from aggression. As one is running away, they get bit on the rump. The two hamsters should be separated. Coco should probably see seen by a veterinarian as antibiotics might help the wounds heal more rapidly. Good luck.

With these pictures, I would guess she is pregnant. Gestation for a hamster is 15-18 days. On the third photo, it appears as if her mammary glands are developed. Usually hamsters start building a nest site in a corner. I would definitely separate her from the male as they can be aggressive during birthing. It is important to allow the female to have a quiet, minimally disturbed environment, especially during their first litter, to decrease the chance of rejection of babies by the mother.

There is a good chance that 2 adult male hamsters will fight and induce significant injuries. If you would like to try to introduce them to each other regardless, I would start with a completely clean cage with fresh bedding and keep them on either side of a mesh divider so that they can see and smell each other without being able to fight. I do not recommend putting one into the other’s cage as the original hamster will likely become extremely territorial. For 2 weeks or so, you can remove the mesh divider for short periods of time while you are carefully monitoring them and offering plenty of enrichment in the form of shelters, toys, food treats to keep them occupied. If you notice any aggression, I would give up and keep them separate from then on. If after several supervised periods alone (about 30 min each time) over 2 week you do not notice any signs of aggression, you may remove the mesh divider but examine them carefully each day for scabs/wounds especially on the rumps, genital area, hind legs. Good luck! They are very cute!

Thanks for using Petco Pet Education Center, formerly Petcoach! Hamsters can get aggressive, especially around their young. I recommend handling the young as little as possible to prevent Khaleesi from being aggressive towards you or from taking it out on her pups. While it is less likely at this age, hamsters can even canibalize their young when they are stressed. Hamsters can typically be weaned (start eating dry food, no longer needed milk from the mother) at about 3 weeks. I recommend separating them into different cages or homes to prevent the hamsters from reproducing. You should also separate Khaleesi from the male hamster if you wish to prevent further breeding. Once the pups are gone, Khaleesi should resume her normal behavior towards you. I hope this helps!

Thanks for reaching out about Princess and including photos. Hamsters can be touch, socially. Continued de-sensitization might help, but also by looking at the photos, your access point seems to always be from above. A large human hand coming down to grab from above can be scary. If you use a cup to scoop her up (gently) and then place her on a flat surface, is she still aggressive? Maybe she is defensive of her enclosure, and might be more timid when out. Lastly, having her spayed might decrease aggressive, but a big surgical procedure. Good luck.

It's most definitely due to fighting, they are known to be fighting when kept together, for this reason it is recommended to have only one hamster per cage. unfortunately many pet shops tend to give false information about this, they don't warn you about this issue but this the unfortunate truth. i recommend separating them into 2 different cages.