A newborn fennec fox has emerged from its nesting box at Sydney's Taronga Zoo and the energetic kit has been keeping its parents busy.

The kit was born in December and is the first born at the zoo since 2013.

Taronga Zoo's carnivore unit supervisor Louise Ginman said the fennec fox was the smallest fox species in the world, despite its enormous, bat-like ears.

"They weigh in anywhere from about 800 grams up to 1.4 kilograms," she said.

The kit weighs just 640 grams and has begun to sample foods that its wild cousins enjoy — crickets, mealworms and small reptiles.

Louise Ginman said the kit was "a bundle of cuteness" and was in excellent health, having undergone vaccinations and microchipping.

Keepers remain unsure of the kit's sex, but they suspect it may be a female.

Ms Ginman said the fox's parents, Kebili and Zinder, had been doting on their new arrival.

"Fennec foxes work very closely together to protect their territory, to protect the kit and bring food to it," she said.

Fennec foxes' ears help them keep cool. ( Supplied: Taronga Zoo )

Cheers, big ears

Sydneysiders might have been complaining about the sweltering heat over the past month, but the fennec foxes at Taronga have not been too concerned.

The species thrive in desert environments thanks to the small size of their bodies and their enormous ears.

"Those ears are great for ... thermo-regulation, for allowing heat to pass out of the ears so they don't overheat," Ms Ginman said.

"These little guys tend to be very active at night time.

"As soon as it starts to get dark, that's when the fennec fox really comes alive."

And the fennec fox kit is particularly playful, seizing any opportunity for a bit of fun.

"They're so playful at this young age, everything is just fun and games to them," Ms Ginman said.

"A moving piece of grass is something to pounce on and tug-o-war with and play with.

"The parents' tails … are sources of play and entertainment."