"Until Sunday the baby elephant had managed to do his business completely unobserved," said carer Mario Hammerschmidt.
But the truth will out, and in the end the vets and zoo attendants had to admit they had missed a little something.
It's easier than one might think with elephants, as pachyderms' male member is discreetly hidden away in a pouch unless they are urinating or otherwise making use of it.
Mother elephant Kewa had a simple delivery without any help from zoo attendants or vets overnight at the New Year - in fact, the baby was a big surprise when attendants came to feed the elephants on the morning of New Year's Day.
"I actually needed two breaths to understand that the newborn was standing there," said zoo keeper Mario Klenz.
Elephant pregnancies normally last 22 months, and staff at the zoo had expected the birth to come at the end of January.
The new baby weighs around 100 kilos and is nursing regularly from her mother. Despite arriving a little early, he is standing and walking - feats that young elephants typically take just half an hour and two hours, respectively, to master after birth.
The baby elephant born on New Year's Day at Berlin's Tierpark, pictured on Monday. Photo: DPA
"What a New Year's gift," said Zoo and Tierpark director Andreas Knieriem. "New Year babies are always something special, but a healthy New Year's elephant baby is very rare and we're very happy."
With the birth of the as-yet-unnamed baby, the herd in the Tierpark now numbers six African and seven Asian elephants, after the new arrival's father, 32-year-old Ankhor, was given away to Prague zoo in August 2014.