Streaky the Super Cat is the Pet of Supergirl, AKA Linda Danvers. Streaky is not from Krypton, but is an ordinary house cat from Earth. Supergirl was trying to create a cure for Kryptonite poisoning, and accidently exposed her pet cat Streaky to one of her experiments, a derivitive of Kryptonite that she created called Kryptonite-X. This new substance gave Streaky the Supercat powers far beyond those of mere mortal cats.
Supergirl tried to dispose of the Kryptonite-X, but Streaky was too smart for her. The chunk of Kryptonite-X now resides in Streaky's yarn ball. Streaky's super powers are only temporary, so he must recharge his powers with the Kryptonite-X every so often. Supergirl does not know about the Kryptonite-X in Streaky's yarn ball, nor his need to recharge his super powers. It would seem that cats from Earth are smarter than people from Krypton.
~ Click on Streaky to read his origin ~