SEEING a 2000kg rhino act "a little hormonal" may sound like scary business.
But for the team at Australia Zoo, it is the most exciting news of the year.
Inyeti, a six-year-old southern white rhino, is expecting her first calf.
It is the first successful conception for the zoo's rhino breeding program and comes just one year after the birth of 600kg Savannah.
For Robert, Bindi and Terri Irwin, it was a special Mother's Day surprise.
"It is huge news for us, being the first baby for Inyeti and the first conception here at the Zoo," Terri said.
"It was very exciting news when we found out she was expecting and there is a great buzz around the zoo now."
Inyeti arrived from Western Plains Zoo in NSW in 2010.
THE plan was to breed her with first-time dad DJ - a nine-year-old white rhino stud.
Terri said the arrival would be a win for the survival of the white rhino.
Its numbers are estimated at just 20,150 in the wild, with a further 780 in captivity.
"It is vital that we keep working to save this species, not just here at the zoo but through our work in Africa and putting an end to poaching," she said.
"Our new arrival is exciting news for the species and one more step in the right direction for protecting these magnificent creatures."
The conception was caught on camera while Bindi was filming Bindi's Boot Camp at the Zoo's Africa enclosure.
"Bindi had to stop filming for 30 minutes because DJ and Inyeti were mating in the background of her shot," Terri said.
"At least we have some idea of when the baby was conceived."
It will be at least 16 months before the new rhino is born.
The expected arrival date is in April next year.
Curator Kelsey Engle said Inyeti would make a wonderful first-time mum.
"She is very good with Savannah, Caballe's little baby - although she is a little hormonal at the moment," Mrs Engle said.
"She has all the makings for a great mum when the calf finally arrives.
"Now we just have to wait."
Inyeti's baby rhino is expected to weigh about 60kg when it is born.