A beachcomber’s guide to finding and identifying mermaid’s purses

If you have ever been beachcombing for treasures along the shoreline then you may have been lucky enough to find a mermaid’s purse. They may not look like much, but these dried-out leathery pouches are actually the used egg cases of sharks and skates, created to develop and protect their babies.

Around 43% of all Chondrichthyes species (cartilaginous fish including sharks, rays, skates and chimaeras) give birth to their offspring in these purses. Between them they produce a diverse array of different types, sizes and colours, that eventually wash up on our beaches when they’ve been emptied.

However the egg cases can still be valuable even after they’re discarded, they provide an insight into the hidden lives of sharks and are also very useful for conservation work. So here is a quick guide on how to find and identify different egg cases, as well as how you can help researchers out.

What is a mermaid’s purse?

There are two types of reproduction amongst sharks, rays and the other ‘non-bony’ fish (known as Chondrichthyes). The first is viviparity, where mothers give birth to live young known as pups like mammals such as us, the second is oviparity, where mothers lay undeveloped eggs in specialised cases like birds and reptiles.

Most large species of shark and all true rays are viviparous and give birth to live young, whereas the smaller shark species such as catsharks and a sub-family of rays known as skates are oviparous.

Instead of developing their young in-utero and giving birth to them, they produce egg cases that act as a detachable uterus to develop and protect their offspring separately.

They are often laid on the seafloor in places such as seagrass meadows or rocky crevices to hide them from predators. It is these egg cases which are commonly referred to as mermaids’ purses.

Egg case 101

As the name suggests egg cases initially contain the fertilized egg of a shark or skate, which over time develops into an embryo. They are made out of the fibrous protein collagen which forms tough leathery pouches.

Almost all egg cases contain a single egg, although big skate and mottled skate cases can contain up to seven. After the cases are released from the mother they provide the embryo with all the nutrients and energy it needs to develop, including oxygen-rich seawater which can be absorbed from its surroundings.

This process usually only takes a few months for most species, however in some species like the critically-endangered white skate it can take up to 15 months. Once the babies have reached a point where they can survive on their own without their purses they swim out of a small opening at the top of the case and leave their ‘artificial mother’ behind.

To see developing embryos inside egg cases for yourselves, check out the amazing video below.

Where can you find them?

Once the baby sharks and skates have fully developed and left their purses, the empty casings are then carried around by ocean currents and occasionally wash up on our shoreline.

The best place to find a mermaid’s purse is therefore at the high tide line on most beaches. The high tide line is easily identified by the long bands of dried seaweed that stretch across a beach.

It is actually amongst the seaweed where you are most likely to find a purse, but you have to look closely because the dried out cases look very much like the seaweed they are surrounded by.

If you have no luck at the high tide line, then the next best place to look is in rock pools, because they can often get trapped in them as the tide goes out.

You won’t always be able to find a mermaid’s purse every time you go to a beach, but don’t let that stop you searching other areas or coming back for another go at a later date.

Different types of egg cases

Whilst there is a clearly defined shape and structure to most egg cases there is also a large variety of different sizes, types and variations between species, much like how different birds lay their own unique eggs.

The general appearance of a mermaid’s purse is a black or brown leathery pouch with either tendrils or horns coming off each or either end. For catsharks the pouch will tend to be more rounded and have long spindly tendrils, which can often get wrapped around in seaweed or other egg cases. For skates the pouches tend to be more rectangular and have defined horns in place of tendrils.

A more bizarre example is chimaeras who produce bottle-shaped pouches with a pair of feathery fins down its sides or the bullhead sharks who produce spiral auger-shaped egg cases designed to get wedged into crevices between rocks. However it is unlikely you will find these more bizarre designs, especially on your first try.

Identifying what you have found

So how do you figure out which species has produce the egg case you have found? One of the big problems with identification is that purses you find on the beach are dried out and so often misshaped or decoloured.

Therefore the best way to make a successful identification is to take it home and re-hydrate it. You can do this by placing it in a bowl of water, preferably from the sea, for a couple of hours. You will notice that it will change shape, get darker and will feel more slimy if you touch it.

At this point you might also be able to find the opening the juvenile shark or skate swam out of when it was fully developed. Now you have a re-hydrate eggcase you will be able to determine more details about the shape, size, colour and any other features you need to make a successful ID. For the best results use online guides (like this awesome one by Marine Dimensions) and you will then know for sure what you have found.

Reporting your findings 

Finding and identifying mermaids’ purses can be great fun for young children on family outings or just avid shark enthusiasts, but it can also provide really important and helpful information for marine researchers. Egg cases provide clues as to where certain species of shark or skates can be found, especially the nursery grounds that are important for juveniles.

This information can then be used to help inform conservation measures to help protect sharks and rays across the world. Citizen science projects involving egg cases can be found across the world online. However if you  in the UK, where we have a lot of catshark and skate species, then you can report your findings to the Shark Trust’s Great Eggcase Hunt.

Just remember to record where and when you found your case in the first place. Once you have made your contribution to science then why not keep your specimen or even start your own collection. If you leave your case in a warm dry place for a few days it will dry out properly and will stay intact for years.

Archaeologists Unearth 2500-Year-Old Settlement in North Macedonia

Recent archaeological excavations at Gradishte, near the village of Crnobuki in North Macedonia, have unveiled a significant ancient settlement that challenges previous assumptions about the site’s historical importance.

Initially thought to be a mere military outpost established to fend off Roman incursions, the findings suggest that Gradishte was, in fact, a thriving city with a rich cultural and economic life, predating the Roman Empire by centuries.

The research, conducted by a collaborative team from Cal Poly Humboldt and Macedonia’s Institute and Museum–Bitola, has revealed that the acropolis of Gradishte spans at least seven acres.

This expansive area has yielded a wealth of artifacts, including stone axes, coins, a clay theater ticket, pottery, game pieces, and textile tools, all of which provide concrete evidence of a prosperous settlement dating back to at least 360 B.C.

Archaeologist Nick Angeloff has even posited that this site may represent the lost capital of the Kingdom of Lyncestis, an ancient polity established in the seventh century B.C. “This discovery is significant,” Angeloff stated.

“It highlights the complex networks and power structures of ancient Macedonia, especially given the city’s strategic location along trade routes to Constantinople.

Historical figures such as Octavian and Agrippa may have traversed this area en route to confront Cleopatra and Mark Antony at the Battle of Actium.” The site, first mentioned in literature in 1966, remained largely unexplored until recent years.

Modern archaeological techniques, including ground-penetrating radar and drone-deployed LIDAR, have facilitated a deeper understanding of the settlement’s size and influence. The discovery of a coin minted during the lifetime of Alexander the Great (325-323 B.C.) has pushed back the timeline of the city’s establishment, suggesting human occupation may date back to the Bronze Age (3,300-1,200 B.C.).

Engin Nasuh, curator-advisor archaeologist at the National Institute and Museum–Bitola, emphasized the importance of these findings: “We’re only beginning to scratch the surface of what we can learn about this period. The discoveries not only illuminate North Macedonia’s past but also contribute to a broader understanding of ancient Western civilization.”

The artifacts unearthed at Gradishte, including charcoal and bone samples, have been dated between 360 B.C. and 670 A.D., indicating a long period of habitation and cultural development.

This ancient Macedonian state, one of the earliest modern states in Europe, played a crucial role in shaping the political and cultural landscape of the region.

As the excavation continues, students, faculty, and researchers from both institutions are dedicated to uncovering the full story of this ancient city. Nasuh likened their efforts to assembling a large mosaic, where each new discovery adds a piece to the overall picture of early European civilizations.

“This ongoing work promises to reveal more about the intricate networks and vibrant culture of ancient Macedonia,” he concluded. “With each subsequent study, we are one step closer to understanding the complexities of our shared history.”

The findings at Gradishte not only reshape our understanding of North Macedonia’s historical narrative but also highlight the interconnectedness of ancient civilizations, offering valuable insights into the development of early European states and their lasting influence on the world.

The World’s Smallest Elephants Led Unusually Long Lives

Ancient elephants that would have been born the size of a puppy lived for decades more than previously thought. Researchers studying an ancient miniature elephant that lived on Mediterranean islands found it could have lived for over 68 years, which is unusually long for a mammal of its size. The smallest-ever elephant took a leisurely approach to growing up, with a drawn-out development lasting up to 15 years.

Though it was barely a meter tall, a team of European scientists found that Palaeoloxodon Falconeri grew much more slowly than its modern relatives, with modern African bush elephants entering adulthood four years earlier than their extinct relatives despite being much bigger.

Their findings contradict previous studies which suggest P. Falconeri would only have lived for 26 years, suggesting that the species would have lived for at least seven decades, and perhaps even longer.

Professor Meike Köhler, the paper’s lead author, says, ‘Traditionally this species had been considered to have a rapid development, reaching sexual maturity early and having a short life. Our work reveals that the life history of this elephant was much slower.

‘Organisms that grow at slower rates have fewer errors in biosynthesis which leads to an extended lifespan.’

Dr Victoria Herridge, who researches fossil elephants at the Museum and co-wrote the paper, says, ‘It’s hard to know why these elephants grew so slowly. There is an idea that the islands had limited resources and predators, so on the one hand food is scarce, but on the other, there is very low mortality.

‘This would allow for a slower investment in growth over a longer period, but without paying the price that smaller individuals pay on the mainland, such as a death in the jaws of a predator. However, the reasoning behind that is still debated.

‘There’s a lot we don’t know about this species, but its slower growth shifts our thinking a little bit on how these elephants evolved.’

Bigger is better

It’s been known for some time that when it comes to mammals and birds, larger animals live longer. While some shrews live for little more than a year, mammals at the other end of the weight spectrum can live for centuries.

The bowhead whale, which can grow up to 18 meters long or about the length of a bowling alley, has been estimated to have been over for over 200 years. Some bowheads have lived so long that they still contain Victorian harpoons used to try and kill them over a century ago.

While the relationship between size and lifespan generally holds across mammals and birds, lifestyle can have an impact. For instance, flying animals generally live longer than their ground-dwelling relatives, with small bats living for much longer than rats and shrews of a similar size.

However, there are a few notable exceptions. Naked mole rats can live for around 30 years, while humans have used technological innovations and medicine to allow us to live for longer too. Previously, it had been thought that the miniature elephants fitted well with the overall pattern.

After diverging from the largest elephant to ever live, the straight-tusked elephant, it was thought that P. Falconeri would have shortened its lifespan as it dwarfed over the millennia it was isolated on what is now the island of Sicily.

‘Palaeoloxodon Falconeri is the smallest elephant ever to have existed, living on both Malta and Sicily,’ says Victoria. ‘At the time, we didn’t know if the area was one large island or an archipelago in the Mediterranean.

‘They are remarkable animals. They were around a meter tall, which is about the same size as a newborn African elephant but they were adults. As babies, they would only have been the size of a puppy.’

While little is known about the species’ life, it is assumed to have grown smaller through a process of miniaturization which is common to many island species due to a lack of resources, predators and competitor species. Looking at the overall trend in life history for mammals, it was estimated that an elephant of this size would live for at least 26 years.

The new study analyzed the growth of teeth, bones and tusks from Spingallo Cave, near Siracusa in southeast Sicily, to provide a more accurate estimate, which shows the species is an exception to the rule.

Professor Antonietta Rossa, from the University of Catania, Sicily, where the fossils are housed and coauthor of the study, says, ‘Spinagallo Cave is outstanding for the number of remains. This abundance of bones provides enough material for analyzing specimens of different ages and growth stages.’

Good things come to those who wait

The researchers found that across the different types of remains studied, P. Falconeri grew very slowly. Though elephants are generally already slow-growing, this species was even more so. While most species grow rapidly as an infant before slowing down after reaching adulthood, the Sicilian elephants grew at a fairly constant rate throughout their entire lives.

Even the oldest specimens grew only two millimeters a year more slowly than the youngest, while the difference for African bush elephants is around a centimeter a year.

However, this slow growth was compensated for by a much longer developmental period, with some bones not showing signs of adulthood even by the age of 22. The age of sexual maturity was similarly delayed, with all evidence pointing towards 15 years in P. Falconeri, compared with 12 years in living African elephants.

‘Given the later age of sexual maturity, their gestation period may also have been longer or similar to large African elephants,’ says Victoria. ‘And of course, those newborns would also take a long time to grow up, leading to long generation times.’

Researchers have suggested that this long period of development could have resulted from a lack of predators in Sicily. This would allow the elephant to grow more slowly as there was little danger of infants being hunted.

As it was less likely to die, this meant that there was less evolutionary pressure for P. Falconeri to grow up fast and reproduce. As a result, selection pressures instead drove it to grow slowly, allowing more time for learning and development over decades rather than years.

However, this slow development would have put it at a disadvantage when it came to sudden changes. Longer development means that evolution acts more slowly, requiring many generations to make significant changes.

‘By taking the inferred age of sexual maturity we can see their gestation period may have been similar to large African elephants,’ Victoria says. 

‘Even though it’s a lot smaller than a full-sized elephant, it’s behaving like a very large animal in terms of its generation time which makes it more vulnerable to extinction. 

‘Island populations are already vulnerable to extinction because they are often unique and not very numerous so it all adds up.’

The period in which P. Falconeri lived was one of dramatic environmental and climatic change, with Sicily changing tectonic activity and sea level. This could have put even more pressure on the elephant’s limited resources and may have led to its extinction around 400,000 years ago.