Little Rupert, who is so small he can fit in an adult's hand, was born after vets failed in their battle to save his mother.
Orphan: Vets were unable to save his mother
At just six inches tall and weighing just over a pound, he is now in an incubator in the
intensive care unit at Tiggywinkles Wildlife Hospital in Buckinghamshire.
He has only recently opened his eyes.
Les Stocker, founder of Tiggywinkles, said: 'Rupert's mother had very severe injuries.
We brought him out and got him breathing and then he went into an incubator on oxygen.
He is now being fed by a tube.'
Tucked up: Rupert in an incubator
Dear deer: Rupert pulls a striking pose for the camera
Staff are optimistic Rupert, now five days old, will make a full recovery.
'Deer are very, very tricky but this one has spirit. He's an extremely feisty little guy and quite pushy,' Mr Stocker said.
Asleep: Rupert takes 40 winks