Wild File: Shark egg cases
Also known as mermaids’ purses, egg cases come in many different shapes and colours. They range from cream and butterscotch to deep amber and black, and between 4 to 25 centimetres long. They can be smooth, have ridges, curling tendrils, or simple appearance.
Wild trivia
- In rare cases, sharks in captivity have laid eggs that hatched without a father, a phenomenon called parthenogenesis.
- Depending on the species and water temperature, incubation inside the egg can take a few months to three years!
- Not all sharks lay eggs, only about 30-40% of sharks are oviparous, meaning they lay eggs.
[Image changes to show a blue screen with a navy blue text box, and text appears: Searching for shark and skate egg cases]
[Image changes to show Helen O’Neill talking to the camera, and text appears: Helen O’Neill, Research Technician]
Helen O’Neill: Egg cases can be found on any shoreline, and they're usually up along the strand line, where if the waves push the egg cases or the wind blows them up.
[Image changes to show a rear view of Helen walking along a stony shoreline]
They're usually hidden amongst seaweed, so you can find a stick or something and you can poke through looking for egg cases.
[Image changes to show Helen talking to the camera]
They can be quite well disguised, so you have to look quite carefully.
[Image changes to show Helen walking along a stony shoreline towards the camera, and then bending down to pick up something, and then the image changes to show a shark egg beside a 50 cent coin]
Um, they can often look like seed pods or other things, and make sure you take a great photo and include a scale bar if you can, because that helps with our identification.
[Images move through to show Helen talking to the camera, Helen measuring a shark egg, and then tweezers placing a shark egg into a jar of clear liquid]
And if you submit that finding, we then can verify that egg case, what species it belongs to, and that helps us learn more about where these animals are and where they’re, more importantly where they're laying their eggs.
[Image changes to show Helen talking to the camera]
So these could be important nesting and nursery areas for these species on which they rely to survive.
[Music plays as image changes to show a blue screen with a navy blue text box, and text appears: Looking for egg cases in the ocean]
[Image changes to show Helen talking to the camera, and then the image changes to show two divers swimming underwater]
You can also find egg cases underwater if you're diving or snorkelling.
[Image changes to show Helen talking to the camera, and then the image changes to show a shark resting beneath a reef]
Um, these are really great and interesting records for us because you can see what habitat the egg case is associated with because they have different modes and methods of playing and attaching their eggs to the seafloor.
[Image changes to show Helen talking to the camera]
It's important not to touch these ones so that it's then may contain the developing embryo inside but these are great records for us. So if you're out in the water and you see one, that's great if you can get a photograph.
[Music plays as image changes to show a blue screen with a navy blue text box, and text appears: Why is citizen science important?]
[Image changes to show Helen talking to the camera]
Sharks, skate and chimaera, which are a relative of sharks, have lots of different modes of reproduction.
[Image changes to show Helen placing two shark eggs into a jar of clear liquid, as a text box appears on the left, and then the image changes to show Helen measuring shark eggs, and text appears: *Oviparous Sharks]
One of the modes that we've been researching here at CSIRO, the Australian National Fish Collection, is the oviparous sharks, which are sharks that lay eggs, um, just like a bird would.
[Image changes to show Helen talking to the camera]
Uh, we have been trying to learn more about these as for some species, we don't know what the egg case looks like.
[Image changes to show various shark egg specimens, and then the image changes to show Helen talking to the camera, and text appears: Egg collectors, By Helen O’Neill (ANFC), 19/11/2020]
So we've been researching them for the past few years, trying to piece together, um, what egg belongs to what specimen, what species, and where they may lay their eggs and at what time of year. Shark, skate and chimaera egg cases can come in a wide variety of different shapes, sizes, colours and you can see what you could find in your local beaches.
[Music plays as image changes to show a white screen with the CSIRO logo above text: Australia’s National Science Agency]
Wild File: Orange-yellow lichens
Lichen grows in a wide range of shapes and forms and can be classified under three main growth forms: crustose – flat and crusty, foliose – leafy or lobed, and fruticose – shrubby or branching. Xanthoria coomae lichen is easy to spot and has a range of visual characteristics. Its leafy, lobed structure is often bright orange or yellow in colour. It grows on tree bark and can be quite common on non-native trees in urban areas.
Wild trivia
- Orange-yellow lichen has been found across Australia EXCEPT Queensland.
- Lichens are tough and can survive in freezing temperatures, in direct sunlight and in dry conditions. Some lichen even grows in Antarctica.
- Dr Cécile Gueidan and their team are testing lichen samples to see if it can survive on the moon!
[Image changes to show a blue screen with a navy blue text box, and text appears: About yellow-orange lichens in Australia]
[Image changes to show a medium view of Dr Cecile Gueidan talking to the camera, and text appears: Dr Cecile Gueidan, Research Scientest]
Dr Cecile Gueidan: Hi, I’m Cecile Gueidan and I work at CSIRO at the Australian National Herbarium.
[Image changes to show a close view of Cecile talking to the camera as she’s pointing to a lichen on a tree trunk]
So this lichen is quite common on the urban trees across Australia and especially in the south east.
[Image changes to show a medium view of Cecile talking to the camera as she’s pointing to a lichen on a tree trunk]
So the colouring is quite striking, this sort of yellow orange colour which is different to these other species that go around that is more yellowish green.
[Camera zooms in on Cecile’s finger pointing at the lichen on the tree trunk, and then the camera zooms out as she continues talking to the camera while pointing at the lichen]
Um, also what's quite striking are the little uh, cup shape structure that you find, uh, in the centre of, of the lichen.
[Music plays as image changes to show a blue screen with a navy blue text box, and text appears: Where can you look for orange-yellow lichen?]
[Image changes to show a close view of Cecile’s hand pointing at a tree trunk covered in lichen, and then the camera zooms in on the lichen]
So you can look for this yellow orange lichen in urban trees in the town where you live, in the countryside.
[Image shows Cecile’s hand appearing again pointing at the lichen]
It will be present if you are in the southeast of Australia on, on various trees.
[Music plays as image changes to show a blue screen with a navy blue text box, and text appears: Is orange-yellow lichen found in Queensland?]
[Image changes to show Cecile’s hand pointing to lichen on a tree trunk]
It might be there.
[Image changes to show Cecile looking through a microscope]
It is found in the northern part of New South Wales, so it is possible that it's also present in the southern part of Queensland.
[Music plays as image changes to show a blue screen with a navy blue text box, and text appears: How do citizen scientist observations help?]
[Image changes to show Cecile walking along a storage hallway towards the camera before going through a doorway on the right]
People’s sighting on iNaturalist are very useful to us.
[Image changes to show Cecile’s hand’s getting small specimen sample jars out of a box, and then the camera zooms in on a specimen sample jars her hands pick up]
They allow us to understand better where those species occur across Australia.
[Image changes to show a rear view of Cecile looking through a microscope, and then the image changes to show a white screen with the CSIRO logo above text: Australia’s National Science Agency]
They are only very few people working on lichens in Australia, so having citizen scientists look around for us where the species occur is really useful.
[Music plays]
Wild File: Wattle
What to look for
Wattles come in all shapes and sizes and have an enormous diversity of floral, leaf and plant forms. Their diverse characteristics have made classifying them difficult. All wattle seedlings start out with fern-like leaves. Some wattles, such as the Black Wattle (Acacia mearnsii) retain these feathery fern-like leaves for their lifetime, but a large group of wattles ditch leaves in favour of what are called phyllodes.
Though they do the photosynthetic work of a true leaf, phyllodes are instead flattened leaf stalks which look like leaves. Phyllodes are thought to be an adaptation to dry conditions. They lose less water than true leaves, enabling wattles to spread to the drier parts of the Australian continent.
Wild trivia
- Golden Wattle seeds went to the International Space Station in 2020 for seven months to see how microgravity affects plant growth.
- Each denomination of the new Australian bank notes features a different species of native Australian wattle.
[Image changes to show a blue screen with a navy blue text box, and text appears: Where can you find wattle in Australia?]
[Image changes to show a blossoming yellow wattle tree, and text appears: Tasha James, Australian Tree Seed Centre]
Tasha James: People can look for wattle all over Australia.
[Image changes to show a close view of yellow wattle flowers]
It's very easy to spot with its bright yellow flowers and can be found in most vegetation areas.
[Music plays as image changes to show a blue screen with a navy blue text box, and text appears: Why do we store wattle seeds in the collection?]
[Images move through to show Tasha James’ hands using tweezers moving wattle seeds in a petri dish, Tasha getting a tin off a shelf, and the camera zooms in as Tasha opens the tin to place bags in]
The seeds that we have at the Australian Tree Centre is used for a number of reasons and these can include for plantations, research and conservation purposes and they can get sold or used with a number of different partners all over the world.
[Music plays as image changes to show a blue screen with a navy blue text box, and text appears: What tests do you do with the seeds?]
[Images move through to show Tasha working in a lab, tea strainers in a beaker on a hot plate, gloved hands removing the strainers, and then Tasha’s hands emptying the strainers into a petri dish]
The tea strainers that we use for the germination tests of the wattle seed help contain the seed while we boil it, which can break the dormancy and be a bit of a heat treatment for the wattle so that it can get through it’s hard seed coat.
[Music plays as image changes to show a blue screen with a navy blue text box, and text appears: How are you planting the seeds?]
[Images move through to show Tasha’s hands writing on a petri dish, Tasha’s hands using tweezers to move wattle seeds in a petri dish, and then Tasha pulling out a tray of petri dishes and checking them]
I'm planting the wattle seeds onto the vermiculite substrate so that they can germinate in our cabinets, and I can count how many are successful and establish the viability of each seedling.
[Music plays as image changes to show a blue screen with a navy blue text box, and text appears: How long have these seeds been growing?]
[Images move through to show Tash opening a fridge, Tasha’s hands pulling out a tray of petri dishes, and then a close view of the wattle seedlings in the petri dishes as the camera pans right]
These ones have been going for about a week. They're doing pretty well and they get pretty big by this point.
[Image changes to show Tasha’s hand counting seedlings on a tray of petri dishes]
And then I'll count them out and then see how many further grow from now.
[Music plays as image changes to show a white screen with the CSIRO logo above text: Australia’s National Science Agency]
Register for CSIRO Wild Watch to support Australian research
By observing and recording local flora and fauna as part of CSIRO Wild Watch, you contribute valuable data directly to Australian researchers via the Atlas of Living Australia—our national biodiversity database, hosted by CSIRO. Each week, Australian observations uploaded to the iNaturalist app are integrated into the Atlas of Living Australia. This means your contributions go straight to the researchers who need them.
[Image changes to show Dr Stephanie Chen talking to the camera, and text appears: Dr Stephanie Chen, CSIRO Postdoctoral Fellow Digital transformation of biological control research for invasive plants]
Dr Stephanie Chen: I'm Stephanie, I'm a plant scientist at the National Research Collections Australia at CSIRO.
[Image changes to show Andera Wild talking to the camera, and text appears: Communications Advisor, National Research Collections Australia]
Andrea Wild: I'm Andrea Wild, author of three CSIRO books - AmAZed, Wild Collections and The Very Stinky Fly Hunt.
[Images move through to show Stephanie talking to the camera, Andera and a female listening to Chen talking, and then Stephanie talking to the camera again]
Dr Stephanie Chen: Thank you for taking part in CSIRO's Wild Watch. Recording your sighting will help scientists like me understand Australia's biodiversity and help protect our environment.
[Music plays as image changes to show a blue screen with a navy blue text box, and text appears: About CSIRO’s National Research Collections Australia vaults]
[Image changes to show Andera Wild talking to the camera]
Andrea Wild: I'm standing here in the vault where we store our insects.
[Image changes to show three colleagues walking towards the camera inside the storage vault, and then the image changes to show on person turning a vault’s handle]
Our collections are a record of the biodiversity of Australia and our region.
[Image changes to show a male pulling out a draw container from the vault as a male is watching and talking to him]
Stored safely, protected from insect attack, our specimens can last hundreds of years.
[Image changes to show a women slowly and carefully pulling out a draw container with various insects]
They're like a library of life on Earth.
[Image changes to show hands pulling out a tray of petri dishes with numbered specimens from a fridge, and then the image changes to show Andera talking to the camera]
Our collections contribute to science by allowing scientists to study and understand Australia's biodiversity and help protect and care for our beautiful natural environment.
[Music plays as image changes to show a blue screen with a navy blue text box, and text appears: About our 15 million specimens]
[Image changes to show Andera talking to the camera]
Every specimen in our collections has an amazing story to tell.
[Image changes to show a hand placing a pinned insect box in a display box, a female closing the lid on the pinned collection, a female looking at monitor screens of microscopic specimens]
Some are really beautiful, like our butterflies, but some of the most interesting are tiny things that you might overlook.
[Image changes to show hands placing a microscope slide of insects with other insect slides, and then the image changes to show Andrea talking to the camera]
We have tiny wasps in the collection that look like tea leaves, and they are actually parasites of other insects and they can be used for bio control. So if a pest moth is attacking agricultural plants, we can find a tiny wasp that will attack the eggs or larvae of that moth.
[Music plays as image changes to show a blue screen with a navy blue text box, and text appears: Real-world impact from citizen science]
[Images move through to show Andera talking, Helen O’Neill outside collecting a sample, Helen measuring an egg, Tasha James checking seeds, and Dr Cecile Gueidan using a microscope]
By recording Australia's plants, animals, fungi and algae, you'll be helping scientists here and around the world preserve biodiversity into the future.
[Music plays as image changes to show a white screen with the CSIRO logo above text: Australia’s National Science Agency]
What is CSIRO Wild Watch?
Go wild with CSIRO in National Science Week (9-17 August 2025) when you join CSIRO Wild Watch, our very first national science experiment made for young explorers!
CSIRO Wild Watch calls curious minds— young and young-at-heart— to connect with nature and form a nationwide team of citizen scientists. Together we can understand and protect Australia's unique and beautiful biodiversity.