The zoo says an 11-year-old Indian rhinoceros called Ashakiran gave birth to a male calf on Wednesday night.
It says the birth is very important for the conservation of the species, which is currently listed as "vulnerable" with only about 2,000 left in the wild.
The zoo says Ashakiran went through a pregnancy of about 16 months and was moved from public viewing into a maternity area in mid-January.
It says her baby calf appears to be healthy and feeding well, but its first thirty days will be critical.
This is the first surviving calf for the mother rhino. She gave birth to a stillborn calf in 2011 and then had trouble maintaining pregnancy.
The zoo says it gave oral progesterone — a steroid hormone — to Ashakiran to help her maintain this latest pregnancy.
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