Michelle Olbricht assumed her cats Ash and Ellie were home bodies, with little appetite for exploring the world outside their immediate neighbourhood in Wellington's Island Bay.
That changed, however, when researchers strapped GPS trackers on to the sibling domestic short-hairs and let them roam for a week.
Tracking data revealed how both cats liked to wander well beyond the front gate in their daytime adventures - sometimes as far as several blocks away.
More surprising to their owner, the pets had no qualms risking one of their lives to cross the seaside suburb's busy thoroughfare.
"I was completely dumb-founded," said Ms Olbricht, one of nearly 100 cat owners in the capital whose pets have so far taken part in the collaborative Cat Tracker study.
"I always assumed they were really indoor-sy... I certainly didn't think they wouldn't go any further than a short distance from home."
It's prompted Ms Olbricht to buy new collars and tags for the pair.
But for Victoria University researcher Dr Heidy Kikillus, who is leading the study, the findings weren't too far out of the ordinary.
Since her project began, the total 98 cats so far fitted with harness-mounted GPS units have clocked up a combined 430ha across areas in and outside of Wellington city.
Before its launch, Dr Kikillus had attached small video cameras to the collars of 10 pet cats, providing around 80 hours of footage and a fascinating insight into felines' unseen habits and behaviours.
A $25,000 research prize from WWF helped her expand that work with Cat Tracker - a three-year collaboration between Wellington City Council and Victoria University, based on a similar study in the US.
In New Zealand, there are around 1.4 million domestic cats - that's roughly around one cat for every three Kiwis - and exactly what they get up to when they're away from home has long been a big question for researchers like Dr Kikillus.
There's also been growing debate about how cats, both domestic and stray, could be better managed to protect vulnerable bird species, with the Morgan Foundation controversially calling for pet cats to be fitted with bells, kept inside at all times and not replaced after they die.
For Dr Kikillus, who presented her preliminary findings to the New Zealand Ecological Society's annual conference in Christchurch this week, the new project was an opportunity to potentially balance cat ownership with conservation.
"In essence, cats are really popular pets and important to a lot of people," she said.
"By involving the public, we've been able to learn more about them together - and we are hoping this also means people can make more informed decisions about how they manage their own cats."
In the Cat Tracker project, cats fitted with the devices were first given a short period to get used to the harnesses - for many, these proved too burdensome and had to be removed.
After a week, Dr Kikillus recovered the trackers and reviewed the location data.
"So far, we've found that most cats cover less than 5ha, and the majority also do tend to stick pretty close to home or surrounding homes," she said.
"Probably the smallest home range I've seen so far is less than half a hectare - so that's really just their own house and maybe the neighbour's - but the biggest has been about 100ha, which was a cat that disappeared for about half the tracking period and didn't even bother coming home for several days."
Unsurprisingly, cats in wide-open rural areas typically wandered further than their urban counterparts.
Other tracking studies had suggested larger, heavier cats were the most intrepid, but Dr Kikillus said her study, still at an early stage, was still recording much variation between .individuals that had made it difficult to pick out clear trends.
"Some do nothing, some are rampant wanderers, so hopefully, as we get a larger sample size, we'll be able to find some good predictors to explain that."
Another major part of the study was an online survey, which has so far been answered by around 2500 respondents, three quarters of them cat owners.
Results have indicated plenty of support for measures like de-sexing, micro-chipping and registration.
But the responses Dr Kikillus is perhaps more curious about are those to a question which quizzed owners on how far they thought their cats travelled.
"Obviously, I'm quite keen to match up the survey responses with cats we've tracked so far, because absolutely none of them have remained on their owners' properties."
• A collaborative study between Victoria University and Wellington City Council which has used GPS units to track the travels of cats in the capital.
• Preliminary findings have shown the 98 cats tracked so far have clocked up 430ha of distance - and one cat in the country travelled around 100ha.
• It's hoped the Cat Tracker study will inform future policy around management of cats, which are being blamed for biodiversity decline, particularly in urban areas.