An endangered pygmy hippo has reached six months of age and is "getting quite big" and "boisterous", Bristol Zoo has said.
Hugo was born at the zoo last August, eight months after the death of his sister at the age of five weeks.
Earlier this year, the calf's father Nato also died, after suffering arthritis and suspected skin cancer.
The zoo said Hugo had a "very close relationship" with his mother and was becoming "increasingly confident".
Keeper Sarah Gedman, said: "As he grows he is choosing to spend time on the other side of the pool from [mother] Sirana.
"And he's very clever and is quickly learning behaviours such as opening his mouth on command so that keepers can monitor the development of his teeth."
There are fewer than 2,000 pygmy hippos left in the wild.
They only grow to about 2ft 7in (80cm) tall, which is half the height of a hippopotamus.
Bristol Zoo Gardens is part of an international captive breeding programme for the species which is native to west Africa.