A seven-month-old baby girl survived three days alone with a bullet in her chest beside the bodies of her parents and toddler brother.
Argentines Francisco Lotero, 56, and Miriam Coletti, 23, shot their children before killing themselves after making an apparent suicide pact over fears about global warming.
Their son Francisco, two, died instantly after being hit in the back.
But their unnamed daughter cheated death after the bullet from her dad's handgun missed her vital organs.
Paramedics rushed her to hospital covered in blood when police alerted by worried neighbours discovered the massacre three days later.
The youngster is recovering in hospital in the town of Goya in the northern Argentine province of Corrientes, where doctors say she is out of danger.
Her parents said they feared the effects of global warming in a suicide note discovered by police.