An ‘odd-eyed’ cat with a genetic condition that makes her eyes different colours is stealing the internet’s heart

Niu Nai has different-coloured eyes. 牛奶小奶牛 / Weibo

A black cat with one blue and one yellow eye is warming hearts all around the world.

Niu Nai, whose name means “milk” in Mandarin, has become an Instagram star in China and beyond.

Her owner Clare Zheng, who lives in China, spoke exclusively to INSIDER about social media’s new favourite feline.

Niu Nai is “odd-eyed,” which means she has heterochromia, a genetic condition responsible for her mismatched eyes.

Niu Nai striking a pose for the camera. 牛奶小奶牛 / Weibo

All kittens are born with blue eyes. Heterochromia occurs when a specific gene prevents melanin from reaching one of the eyes during development, causing one of the eyes to change to green, yellow, or brown, according to

Thankfully, heterochromia does not affect vision and isn’t considered a medical problem.

One of Niu Nai’s eyes sometimes looks red in photos.

Niu Nai with a red eye. 牛奶小奶牛 / Weibo

It is common for an odd-eyed cat’s blue eye to appear red in photographs. This is due to the layer of melanin over the blue eye, which can remove some colours of light, according to

Zheng told INSIDER that Niu Nai is aged 3 and a half.

Niu Nai with wings. 牛奶小奶牛 / Weibo

A friend gave Niu Nai to Zheng.

Zheng said Niu Nai “loves to eat and sleep all day.”

Niu Nai has different-coloured eyes. 牛奶小奶牛 / Weibo

“She’s not interested in normal cat toys,” Zheng told INSIDER.

Niu Nai’s Instagram is full of pictures of her taking baths and wearing costumes — and users are loving it.

Niu Nai in a panda outfit. 牛奶小奶牛 / Weibo

Niu Nai’s Instagram account, @milkyblvck, has 34.5k followers.

Niu Nai taking a bath with a rubber duck. 牛奶小奶牛 / Weibo

The Instagram account, which was started in March, has quickly amassed followers thanks to Niu Nai’s stunning eyes.

Zheng says Niu Nai isn’t afraid of strangers and feels great about all the attention she has been receiving.

Niu Nai’s beautiful eyes. 牛奶小奶牛 / Weibo

“This little guy has brought me so much joy since I found about about him, thank you!! ✨,” Instagram user crashandbang1993commented.

“Such a round beautiful kitty,” Instagram user sleepersvoid commented.