Filey Bird Garden and Animal Park had a surprise last week as their female Zebu went into labour.
The arrival of the male calf was a surprise to the park as Rolo, the male Zebu, is castrated and they didn't know Millie was pregnant.
A spokesperson from Filey Bird Garden and Animal Park said: "Millie arrived in the park in November last year so she must have been pregnant the whole time!
"We noticed her gaining weight but so do most of our animals with lush grass in summer.
"She did everything right and we just kept an eye on her to make sure the little Male calf was OK.
"He was up and walking within two hours (be it very wobbly) and was suckling from his mother happily."
A barrier has been placed around the paddock in order to give Rolo, Millie and the new arrival time to bond and keep visitors safe.
"Millie is doing a great job and hiding him away safely between feeds. Rolo is none the wiser that the calf isn’t his and is very protective," the park added.