There is a bit of a mystery surrounding the birth of eagle ray pups at Auckland's SEA LIFE Kelly Tarlton's Aquarium after no males have been in with the female eagle rays for over two years.
According to the aquarium the pups were born on New Year's Eve to two mothers who both reside in the fish tunnel display, which does not currently house a male eagle ray.
In a statement the Kelly Tarlton's team explained there are two ways the female eagle rays, named Nibble and Spot, could have conceived the pups.
“Whilst we were surprised to see Nibble and Spot give birth to pups because they haven’t been with a male in two years, it’s not completely unheard of," says Andrew Christie, Curator at SEA LIFE Kelly Tarlton’s.
"It could have occurred through a process called parthenogenesis, which is a rare reproductive strategy where an embryo develops without fertilisation. Alternatively, Nibble and Spot could have stored sperm inside their bodies for the last two years. Sperm storage has been recorded in several shark and ray species, so we think this is the more likely scenario."
The team was also amazed that Nibble and Spot gave birth at the same time as each other on New Year’s Eve.
Kelly Tarlton's says eagle rays are a type of cartilaginous fish with skeletons made of cartilage instead of bone as well as wide, flat snouts like a duck’s bill.
They are found in New Zealand waters and are easy to identify thanks to their pointed wings and the flapping motion they make when they swim.
The new eagle ray pups will go on display at the aquarium's Turtle Bay exhibit in the near future.