The saying "opposites attract" couldn't be truer than in the case of Casper the Samoyed dog and Romeo, the Himalayan Persian cat.
Not only do they look poles apart – Casper has a happy face while Romeo appears crabby – but they are also very different in temperament.
Their owners are Rinsa Li, 29, and Phee Wei Cheng, 27, of Christchurch, New Zealand.
"Casper is six years old, and we got him as a puppy when we were in Auckland. He moved with us to Christchurch around three years ago.
"Romeo is three years old. We got him as a kitten. He's originally from a small town called Timaru, about two hours' drive from Christchurch," says Li, a photographer who is originally from China.
Phee, an account manager, hails from Butterworth, Penang.
Growing up, Li always had pets so once she moved out of the family house, she wanted to get a dog for herself.
"I remember browsing online one day and saw a photo of a litter of Samoyed puppies for sale. I fell in love immediately and went to check it out.
"Casper was one of two puppies left from that litter. When I saw him, I felt a bond immediately and knew that he’s the one that I had been looking for," says Li.
She also always wanted to get a cat, but was unsure how Casper would react to it.
"When my best friend got a cat, I took Casper to meet them and it turned out that Casper was curious but very gentle and sweet. After this, all my doubts disappeared, and I decided to start looking for my dream cat.
"The first time I saw Romeo, he was sitting in a corner, curiously looking at us. He was the last kitten from that litter. My heart just melted."
Soon, the process of introducing the pets to each other began.
"Even before we brought Romeo home, we would go to Timaru and swap Casper and Romeo's blankets around so they would get familiar with each other's smell," Li remembers.
Then when they brought Romeo home, they separated the pets for almost a week. Romeo stayed in the bathroom and they set up a baby gate to give Romeo some space from Casper.
"Casper was very curious – he knew that we had brought home a new family member. He would always sit by the baby gate and listen to Romeo mewing.
"Romeo was nervous and scared of Casper at first because Casper's so big and fluffy. But after a week, Romeo started to get more curious about Casper but they still kept a distance from each other.
"Casper was so sweet – he would go up to Romeo and smell him. If Romeo got scared, Casper would gently move away and sit at a distance to make sure Romeo felt safe.
"Now, basically they can’t be apart from each other."
Li describes Casper as very well-behaved and sweet. But he is also "stubborn sometimes when he wants attention and wants to play".
"And he gets jealous very easily. If I have friends over and don’t give him attention, he would start to 'talk' a lot and push Romeo away to steal the spotlight."
Li says: "Romeo looks grumpy but he is the sweetest cat I have ever met. He allows everyone to hold him; he’s such a great cuddle. He’s always very playful, and enjoys chasing toys.
"Also, he enjoys taking baths more than Casper! When I call them both, Romeo is usually the one that answers me most of the time.
"It sometimes seems as if Romeo has a dog personality and Casper has a cat personality," quips Li.
Romeo adores Casper and follows him wherever he goes. Sometimes, Romeo loves to surprise Casper by springing on him when Casper passes by.
Every night before bed, Casper would "groom" Romeo, but this only lasts a few minutes before Romeo becomes too demanding. Casper would then push his little brother away. And Romeo would get angry and try to fight back. After that Romeo would retreat to a corner of the house and get ready to "attack", round two.
"It’s so entertaining to watch them play fight over and over again," says Li.
One of the family's favourite things to do is go on road trips and explore the picturesque country.
"We recently came back from a road trip with them for around two weeks in a campervan," says Li.
"We usually go to scenic places like Lake Tekapo, Queenstown, West Coast, and just anywhere with beautiful scenery. We usually bring them on trips every couple of weeks. We try to do more trips in the winter when it is much cooler.
"At home, Romeo will keep an eye on Casper. But when we are outdoors, Casper would always keep an eye on Romeo to make sure he’s OK.