Hairy Marron Breeding Program
This rare and critically endangered freshwater crayfish is only found in a small pocket of Western Australia.
Hairy Marron (Cherax tenuimanus) are large freshwater crayfish that are endemic to the Margaret River.
Due to competition and hybridisation with the Smooth Marron (Cherax cainii), wild populations have declined dramatically. In fact, up until the late 1980s the Hairy Marron and Smooth Marron were considered a single species.
With wild populations dwindling, this species is at serious risk of becoming extinct and is listed as critically endangered on the IUCN’s Red List of Threatened Species.
Breeding program
In 2022, a breeding program was established at Perth Zoo in collaboration with the Department of Biodiversity, Conservation and Attractions (DBCA) and the Department of Primary Industries and Regional Development (DPIRD).
A population of Hairy Marron is cared for behind-the-scenes within Perth Zoo’s Native Species Breeding Program.
Since the breeding program commenced, Perth Zoo has taken a leading role to support marron through all stages of life; from courting and breeding, to egg-laying, hatching and maturing.
The first successful cycle of breeding was achieved in 2022, with a total of 94 craylings hatched.
In the years since, countless new discoveries have been made about this previously under-researched species to refine the husbandry approach with the aim of increasing breeding successes.
Currently, more than 286 craylings have hatched through the program (as at March 2026) and it’s hoped that number will continue to grow.
New behaviours discovered
Maternal instincts
During breeding cycles, Zoo scientists have found the Hairy Marron is more maternal than was previously known.
Marron eggs are held under the mother’s tail for months while they mature.
The mothers were observed gently swishing the eggs to aerate them, stroking them, and flicking off sand and dirt to keep them clean.
These observations revealed a nurturing side to Hairy Marron that hasn’t been recorded before.
Expressions
Over the past couple of years we've learned that Hairy Marron are far more expressive than previously thought.
This video shows a crayling touching sand for the first time and flicking its eyes together to indicate feeling stimulated and intrigued.
Hairy Marron courting
Across breeding cycles, an intricate courtship and mating process for the elusive species has been discovered.
Step 1: Match-making
The Hairy Marron species coordinator considers the genetics of each marron and matches males to females.
Some pairs have been matched for consecutive seasons – like Margo and Jarrah who bred successfully two years in a row.
Step 2: Next door neighbours
A matched pair will be moved into the same tank, but with a barrier down the centre to take things slowly.
Keepers watch closely to see signs of compatibility like antennae touching through the barrier, or gentle touching and holding of each other’s chelipeds (the limb with the claw).
But! If there’s any intentional grabbing or stabbing motions, this pair is deemed incompatible and they are separated.
Step 3: Sleepovers
Once the positive signs have been observed, the barrier is removed and the courtship continues.
The male will become laser-focused on the female, he’ll sleep in the same shelter as her, rush at her and retreat backwards and hold his tail high while facing her.
Meanwhile, the female will be busy cleaning her abdomen and pleopods (the small paddle shaped appendage on the underside of her tail).
This phase can last a week or longer.
Step 4: Mating
When it’s time, the male will start to posture and show he’s ready. He’ll face her, while lifting and flicking his tail, and if she stays close by, he’ll carefully slide underneath her.
The reproductive organs will meet – interestingly, the male organs are found in line with the fifth walking legs, while the female organs are in line with her third walking legs.
According to our records, a mating can last anywhere from one minute up to eight minutes!
Step 5: Egg-laying
Within 24 hours of a successful mating, the female will lay her eggs into her tail and hold it tight like a clam shell - this is called berrying. For the next week, she’ll hold her eggs tight and won’t eat.
If the breeding is successful, the female will hold eggs under her tail for a few months while they mature.
Mothers have been documented gently swishing their eggs to aerate them, stroking them and even carefully flicking off bits of sand to keep them clean.
Partners and supporters
The Hairy Marron breeding program is run by Perth Zoo in partnership with DBCA and DPIRD.