KEY POINTS:
Anna Sjardin- Killick never thought a rat could mean so much to her - but then Frederika is no ordinary rodent.
Mrs Sjardin-Killick bought Frederika almost three years ago for the paltry amount of $8 but since then has spent more than $5000 on her.
Frederika, it turned out, was one very sick rodent and was diagnosed with a condition called mycoplasmosis, which causes her lungs to fill with fluid.
Vets told Mrs Sjardin-Killick her rat would last only a few days at best.
But after hours of research and talking to the Brookfield Veterinary Centre, Mrs Sjardin-Killick has kept Frederika alive far longer than anyone thought possible.
"The vets are always surprised to see her come back for a visit," she said.
Frederika has survived two operations to remove four tumours, and has has many severe infections and too many injections to count.
She also has to have antibiotics every day. The pills have to be chopped and hidden in peanut butter.
Frederika is also kept in a special heated and dust-free room.
"The power bill in the winter is an extra $100 a month alone," Mrs Sjardin- Killick said.
Rats are misunderstood creatures, she said. Most of them are intelligent, clean animals.
"You can actually teach them how to fetch things like dogs can.
"They also have opposable thumbs so they can hold things like humans can. They are more likely to get sick from us than us from them," she said.
Frederika has helped Mrs Sjardin-Killick through some difficult times of her own.
The 27-year-old has battled chronic fatigue syndrome for 10 years and has often been too sick to get out of bed.
She has only recently become well enough to take a part-time position as a Spanish teacher at Tauranga Boys' College and said Frederika had been a huge comfort to her.
"Frederika has been one of my closest friends. She cuddles me and is always happy to see me," she said.
"I have a wonderful husband, an amazing family and very good friends and I consider Frederika one of them."
Mrs Sjardin-Killick said people often question why she would spend so much money on the rat and wondered why she didn't get Frederika put down.
She always responded that the rat was not suffering and enjoyed a nice life.
Martin Earles, a vet at Brookfield Veterinary Centre, said it was unusual for rats to live beyond two years at the best of times but especially unusual if they had a bad respiratory condition.
- BAY OF PLENTY TIMES