The Javan chevrotain mouse deer is one of the smallest hoofed animals in the world.
It was born at Marwell Zoo, near Winchester, weighing approximately 13oz (370g).
Keepers say the calf, born to parents Gus and Gwen in the zoo’s Energy For Life: Tropical House, is doing well.
The arrival is the latest newborn at the zoo which has lost more than £4 million in revenue because of the Covid-19 pandemic.
Tim Rowlands, Marwell Zoo’s hoofstock team leader, said: “We separated the male and female two weeks before she gave birth so she would not be disturbed, even by him, mimicking the natural behaviour of the female taking herself away to find a quiet and secure spot to give birth in the wild.
“All deer species will hide their young until they are older so they will only really come out to feed, then hide again.
“There are very few zoos who care for any of the mouse deer species as they are so small in size, very secretive, and nocturnal, so any youngster born is great news for the conservation breeding programme.
“It’s vitally important that we work to ensure these wonderful animals do not disappear for good.”
The species is found on Java in Indonesia and is hunted and traded for wild meat and as pets.
When born, the young are the size of a rat and can run and jump soon after birth. They suckle only occasionally, and only at night.
