Abandoned rabbits and guinea pigs roaming free in some of Perth's suburbs have been "breeding like rabbits" with the burden falling on volunteers to round them up before numbers get out of control.
For several months, residents in the northern suburb of Carine have raised concerns about escaped pet rabbits living free in the streets and breeding.
The extent of the problem has since become clearer after volunteer group Romeo's Rabbit Rescue caught and removed six mini lop rabbits from the area, including babies and a heavily pregnant female, which has since had four babies.
Group founder Andrea White said there were likely more out there.
"We think the owners just moved out and left them behind," she said.
"They don't usually do well fending for themselves but with all the vegetation to hide in and eat they've survived."
The rescue came just weeks after the group removed a mother and six baby rabbits from underneath a home in Thornlie, south-east of Perth.
Ms White said the situation was not unusual.
"Sadly, it's quite common. The term breeding like rabbits is not a myth. They can have a litter and then a month later have another one," she said.
"It really can get out of hand quickly."
The trapped rabbits are desexed, vaccinated, microchipped, and rehomed.
WA rescue group Guinea Pig Haven has also been fielding more and more calls about abandoned guinea pigs in recent months.
Founder Claudia Lyons said the group had gone from receiving one call every six months to more than 20 calls in the past three months.
"I would definitely say the increased living costs and the rental crisis has very much led to pocket pets getting dumped," she said.
"People can't be picky and don't have the time to wait [to surrender them], so sometimes they're just very desperate and unfortunately need to dump their animal.
"It has been hard the past six months."
The group has been working to rescue a herd of stray guinea pigs found by a local foster carer in Parkerville in the Perth Hills.
Ms Lyons said the animals had taken refuge near a local restaurant and started breeding.
"At the moment, I think we have rescued 10 but I believe there are still others out there."
"[The foster carer] has found babies, females and males, so we are thinking that they have been breeding there. So we are just working on trying to find them all."
Fast-breeding animals like rabbits and guinea pigs have long caused issues for Perth pet owners.
In 2020 RSPCA WA was called out to deal with more than 100 rabbits at a Perth property, and in April this year welfare officers removed 56 guinea pigs from a Wanneroo home.
The RSPCA's executive manager of animal and enforcement operations, Hannah Dreaver, said it was "very common" for people to end up with unwanted litters because it was difficult to tell the difference between male and female rabbits and guinea pigs.
"One of the biggest reasons that we have for these types of animals being surrendered is because they've ended up with two of the opposite sex and ended up with unwanted litters," she said.
Ms Dreaver said pet owners should let a professional determine the sex of their animals or get them sterilised.
She warned people not to release any unwanted animals onto the streets and said it was "worrying" to hear about situations where fast-breeding animals were living on the street.
"Please don't release them into the wild," Ms Dreaver said.
"Once they end up out on the streets, they're even more uncontrolled."
The RSPCA will intervene in situations where there are concerns about animal welfare but urged people to report stray rabbits or guinea pigs to the local council.