Fake rocks are helping rare Australian snakes survive in the wild after builders took their natural homesAdrian Villellas Thu, November 12, 2026 at 6:07 AM UTC
A juvenile broad-headed snake. Credit: Aussie Ark
For years, people have taken natural sandstone from the Australian bush for landscaping. This practice leaves broad-headed snakes without homes.
To address the problem, scientists released six captive-bred snakes back into the wild in May 2026, giving them human-made rocks to live under.
According to the University of Technology Sydney (UTS), this world-first release is working, with at least four of the snakes surviving their first few months.
Six animals is a tiny sample, the count is preliminary, and neither official announcement cites a published or peer-reviewed paper. Yet the scientists behind the study are encouraged.
Thirty-four years in Morton
UTS wildlife ecologist Jonathan Webb leads the program with Aussie Ark and the Traditional Owners of the Shoalhaven. His own field site is a population in Morton National Park, south of Sydney, and he has been counting snakes there for 34 years.
Webb started on the snake during his PhD at the University of Sydney. The species had once been common around Sydney. By the 1990s it was rare, while other snakes were doing fine.
He kept monitoring after the PhD and joined UTS in 2012. “It turned into a long-term study purely by accident,” he said of the 34 years. Internship students still go out with him on the surveys each year.
The snake has a flattened head and a black body with yellow bands, and it grows to about 35 inches (90 centimeters). It lives only on the rocky escarpment of the Sydney sandstone basin and the ranges around it.
Its life runs slowly. A broad-headed snake can take five years to reach adulthood. Females reproduce only every two or three years, and wild adults can reach 23.
Landscapers sell the boulders
Young snakes depend on rock outcrops for shelter and for food, because they eat only small rock-dwelling lizards such as geckos and skinks. Webb said that removing the rocks takes away both.
The state of New South Wales listed bushrock removal as a key threatening process in a final determination dated November 5, 1999. The document names Hoplocephalus bungaroides, the broad-headed snake, among the threatened animals affected.
Webb said the rules need enforcing. He wants a permit system that makes sellers prove their rocks did not come from areas with threatened species.
Landscape suppliers still sell boulders taken from the bush, he said, and a feature boulder can fetch 450 Australian dollars. He called that “really frustrating.”
Weather and fire added to the damage. His monitoring recorded a decline during the 2017-19 drought. Little breeding followed for three years after the 2020 bushfires. By 2023 the population had dropped by around 64 percent.
Captive breeding programs
Aussie Ark secured 17 wild adult snakes in October 2024 to start the captive side of the program. That group later grew to 20 and lives in terrariums at Conservation Ark in Somersby, New South Wales.
Earlier in 2026 the program recorded the first captive birth of the species, Aussie Ark said. A few weeks later, remote-sensor cameras filmed a live birth, which the group described as never documented before.
Eight juveniles have been bred so far. Two stayed in the captive group because of their genetics, and six went to the release sites. Aussie Ark project lead Dylan Wallis and Chief Conservation Officer Hayley Shute let one of them go together.
Each snake carries a unique marking on its head, so staff can identify individual animals during later checks. Captive programs are helping other Australian species too. The University of Newcastle reported a first captive breeding of Littlejohn’s tree frog.
Aussie Ark Ranger Dylan Wallis with Professor Jonathan Webb and the artificial rock habitat. Credit: Aussie Ark. Click image to enlarge.Slabs designed by Benjamin Croak
Dr. Benjamin Croak, who completed his PhD at UTS under Webb, developed the artificial rocks. UTS says they have the right crevice size and mimic the thermal properties of natural stone.
The snakes hunt at night and spend the day under rock, which gives them warmth and cover and also draws the lizards they eat, Webb said. He described the artificial versions as “critical to the survival of the juvenile snakes.”
Croak had worked on the species’ shelter needs years earlier. In a 2013 paper in PLOS ONE with Webb and Richard Shine, he reported radio-tracking nine adults in Wollemi and Yengo national parks.
The snakes spent most of winter beneath sun-warmed rocks. The authors recommended that managers keep existing surface rock in place.
The program also trains and supports Indigenous rangers to monitor the snakes on Country. Traditional Owner Frank Connolly Jr. said the snake is “important to our culture” and that young people are learning the work for the next generation.
Admittedly a tiny sample
UTS, in its note of November 6, says at least four of the six survived the first few months. That is the only survival figure in the official announcements. Aussie Ark’s release note says the six went out under artificial rocks but gives no survival count.
The figure is a minimum from a very small group, a few months after release. UTS says Webb’s team has run fortnightly surveys. Neither note gives the survey results or the date each snake was last seen.
The announcements also describe no comparison group of snakes released without artificial rocks. Webb’s view that the rocks made the difference therefore remains an expert judgment, and UTS still calls the release a pilot study.
Predators are an early risk. Webb named kookaburras and brown snakes among native hunters, along with invasive cats and foxes. In South Australia, researchers confirmed that feral cats killed 74 of 389 reintroduced animals at two sites.
Breeding in the wild is further off. Adulthood can take five years, so the released juveniles have a long wait before they can add to any population. Pressures on snakes worldwide, such as habitat loss, continue in the meantime.
Much more work ahead
Webb said the focus for the next few years will be restoring habitat and releasing more captive-bred snakes at selected sites. Aussie Ark founder Tim Faulkner said the group had spent years “navigating so much red tape” to reach the first release.
One of Webb’s first memories is sitting on his dad’s shoulder while the kid next door let him touch a green tree snake. Going out to check the young broad-headed snakes under their artificial rocks, he said, “I feel like a kid again.”
The information was obtained from the University of Technology Sydney.
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Source: Nature
