As if the aquatic mammals weren’t already cute enough, the Mandurah Estuary now has the addition of four new baby dolphins: Splash, Nikaila, Breeze and one who is yet to be named.
Murdoch University researcher Krista Nicholson said although dolphins can give birth throughout the year, March and April were peak months for calves.
“We had a couple born in January February, but then Autumn is definitely the peak time,” she said.
Though Ms Nicholson is yet to see a dolphin birth in the estuary, she said pregnant dolphins could be identified by their size.
“They become quite enormous… so mainly it’s educated guesses of the size of the dolphin that they might be pregnant. and also if their previous calf is about weaning age – three years old – we’re expecting them to have another calf,” she said.
“Gestation lasts approximately twelve months, so usually the mating and the calving happens at the same time... there’s definitely variability between the females, but generally they have the calves back to back throughout their lifetime.”
Needless to say, it’s a pretty busy time in the estuary for female dolphins.
“They’re roughly a meter in size when they’re born, and you can see, the newborn calfs, you can really see their foetal folds, because the dolphin in the womb has been kind of scrunched up, so when they give birth you can still see the lines on their sides,” Ms Nicholson said.
She said the lines stayed visible until the calf was about six months old.
Dolphin calves are cared for by their mothers until they are completely weaned off milk, which is secreted from the mammary glands found on either side of their mother’s genital slit.
Ms Nicholson said she had noticed that some other mothers will “babysit” calves that are not their own, though there is no formal research into this behaviour yet.
She said that because the calves are still newborn, they are not very skilled or used to boats.
Ms Nicholson suggests people out on the water should slow down if they spot dolphins nearby – not only to ensure the youngster’s safety, but to catch a glimpse of these cute new additions to the local waterways.
