These are Wellington Zoo's resident giraffes and a mother and daughter pair. They are a hybrid breed.
They can be distinguished by markings on their necks. Zahara has a butterfly half way down her neck (the rear giraffe in the above photo) and Tisa has a heart, as shown below.
Tisa is the mother and the largest animal found at the zoo. She is known for being very slobbery.
Zahara is one of 3 giraffes to be born at the zoo and often the first to arrive at the observation deck for grub.
In 2012 Wellington Zoo became famous for performing the second successful caesarean in the world. This was performed on Zahara, unfortunately the calve didn't survive. At the time there were only two published reports of surgeries of this kind and only one, published in 2007, that stated the mother survived the surgery. If you look carefully at Zahara's stomach you can see an extra fold which is the c-section scar.
The giraffes are feed daily at 12.30, with the public being provided with browse to feed them. The browse is usually tree lucerne, silage or another type of foliage. These giraffes seem to love pohutukawa, which is a native to New Zealand and often referred to as the New Zealand Christmas tree.