His lengthy winter stay on Otago’s coast could be a first for the enigmatic subantarctic species, the Department of Conservation (Doc) said.
University of Otago economics professor Paul Hansen said the animal’s stay at Long Beach brought together a collection of "like-minded, lovely people" who checked in on the large marine mammal regularly.
Yesterday morning when Prof Hansen arrived at the beach for his daily check on "Big Boy", fellow fans of the elephant seal told him the young male had left.
"I’m heartbroken, but I’m also overjoyed for him."
His encounters with the animal over the past 40-odd days had been "one of the most magical experiences of my life".
Doc said male elephant seals grew to be 5m and weigh 3600kg, but the juvenile - estimated to be 3 years old - was just over 2m in length.
When Big Boy arrived he would have weighed about 700kg, but because he was fasting when he was ashore, by the time he left he had dropped to about 250kg, Prof Hansen said.
He displayed great strength, pushing logs around the beach in what was understood to be simulating fighting males and herding females, to hold his harem together, or training for the years ahead when he was sexually mature and ready to join a breeding colony.
But over the past five days his weight loss and lack of energy made it apparent he would soon depart in search of food.
"In some ways he behaved a bit like a young sea lion pup, playing with smaller bits of wood.
"He was so good at rolling logs that none of us could pick up.
"He’d roll them over and get them out of the tide and he’d play with them for quite some time.
"That’s a behaviour that I have never ever seen before."
Doc biodiversity ranger Jim Fyfe said the animal was not marked so Doc had no way of knowing where he came from.
Elephant seals were known to come ashore in Otago in the summer when moulting, but this juvenile was "out of season".
"He was in good condition, and nice and fat.
"So he decided he’d go on shore and spend some time pushing logs around, hanging out on shore, sort of practising to be a beachmaster when he’s older.
"He had his favourite log, which he religiously worked out with every day - pushing it around and flipping it over."
Macquarie Island - an island in the southwestern Pacific Ocean, about halfway between New Zealand and Antarctica - was a stronghold for the species, he said.
