A homeless cat in Russia is being hailed a hero after helping to save a baby's life. 

An infant was abandoned on the streets of Obninsk this week, but a long-haired red tabby kept him warm and alerted passersby to his presence. 

The cat, called Masha by area residents, lives on the streets but is fed and cared for by neighbours. Irina Lavrova said she heard Masha meowing and knew something was wrong. 

"She is very placid and friendly, so when I heard her meowing, I thought that perhaps she had injured herself," the Obninsk resident recounted. "Normally she would have come and said hello to me. You can imagine my shock when I saw her lying in a box next to a baby.

"Clearly her mothering instincts had taken over and she wanted to protect the child," Lavrova told Central European News. "He was well-dressed with a little hat, and whoever left him here had even left a few nappies and some baby food."

The baby was taken to the hospital, where he was determined to be healthy. 

"The baby had only been outside for a few hours and thanks to Masha … he was not damaged by the experience," a hospital spokesman confirmed. 

Obninsk residents said they are immensely proud of their hero cat, and showered her with goodies. 

"Everyone in the block is very proud of her," Lavrova said. "We have all spoiled her rotten by giving her her favorite food."