DETROIT (WP) - Cygnus and Arcturus are two Detroit-area cats with some very big claims to fame.

Arcturus, a spotted Savannah who measures 0.48m high, won the Guinness World Record in autumn for tallest domestic cat. His housemate Cygnus, a Maine coon with a 0.44m tail, snagged the world mark for longest tail.

Now they are missing following a fire that destroyed their home.

Their owners are offering a very big reward to whoever finds them and two other cats: US$25,000 (S$34,000) each - or US$100,000 for all four - to be paid in bitcoin.

The sum is a reflection of just how important Arcturus and Cygnus, as well as their brother Sirius and a temporary feline houseguest named Yuki, are to Will and Lauren Powers.

When he woke up on Sunday morning to find their Farmington Hills home ablaze, Will, 32, frantically searched for the cats but could not locate them.

He left several doors open in hopes the cats would escape but search parties have turned up no sign of them.

The couple did not aim to land their pets in the record books, Will said earlier this month on a television talk show.

They got the cats about two years ago, and he concocted what he deemed to be a nutritionally superior feline diet that involved slow-cooked chicken. When he noticed a year later that Cygnus' tail seemed unusually long, he posted a photo on a veterinary forum.

A Guinness team came out to Farmington Hills to measure, and when they noticed Arcturus who is a hybrid between a serval, a kind of African wildcat, and a domestic cat, they decided to measure his height.

The couple are requesting for any financial help to be donated to an animal shelter or the American Red Cross.

"If you want to do anything to help us, do that," Will wrote on Facebook. "If the death of Cygnus, Arcturus, and Sirius isn't meaningless and can help another family love their cats like we loved ours, then this tragedy can have something good come from it."