For over 30 years, a South Australian farmer has conducted surveys of the unique wildlife that lives on her family's 5,000-hectare property in the Coorong, south of Adelaide.
Then, on the weekend, Sally Grundy witnessed an incredible animal behaviour that experts believe has never been captured on camera before - a tiger snake hunting for fish in saltwater.
Grundy was walking along the edge of a barrage off Ewe Island, which is part of Mundoo Island Station, a cattle property with vast reserves set aside for critically endangered migratory birds, including the far-eastern curlew, curlew sandpiper and orange-bellied parrot. She's used to seeing the rare and unusual, but she describes the snake encounter as completely "extraordinary".
Initially, it appeared as if the snake was caught in the rocks. "It was doing a lot of tumble-turning and flipping, but we could not see its head, only its body and tail", Grundy said.
"I thought maybe it was wedged between rocks and stuck there, but then it went out into deeper water and disappeared."
Together with a small group of bird survey volunteers, they waited for five minutes for the snake to reappear, confused by the strange behaviour, and hoping it wasn't injured.
"It suddenly popped up out of the water with the fish in its mouth," she said.
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The vision is some of the most exciting snake experts have seen since a python was filmed eating a platypus in a Queensland creek last year.
The Australian Herpetological Society confirmed its common knowledge that tiger snakes eat fish, but it was remarkable to witness one in the water hunting for prey. Although other species, like red-bellied black snakes, have been observed on occasion hunting in freshwater for carp.
The group's president, Chris Williams, said it was a "real coup" for Grundy to capture the behaviour, particularly in saltwater, and her images have created "a stir" in the reptile community.
"We're aware that these things happen, but it's exceedingly rare to capture so many great images," he told Yahoo, noting he's unaware of anyone photographing it before.
Mundoo Island Station is home to at least three types of snake, red-bellies, browns and tigers. The latter two can vary a lot in colour, and so Grundy was initially unsure which species she was watching.
She began snapping photos the moment the snake emerged from the water, with its neck upright, and a small fish in its mouth.
"It's extraordinary. I've watched snakes for so many years, but I've never seen anything like that," she said. "I've seen snakes eating frogs, but never seen one actively fishing."
The snake then carried the fish in its mouth to some rocks in the shallows, where it swallowed its prey. It then vanished under the water again, and Grundy and her team continued on with their bird survey.