The Black Rock Scorpion, as its common name implies, is a dark-coloured species that is often found living under rocks, although it is just as much at home under logs. It is one of three species of scorpions that can be found in the greater Melbourne region. It is a widespread species and can be found in other parts of Victoria, South Australia, New South Wales, the ACT and Queensland.
Black Rock ScorpionPhotographer: Alan Henderson. Source: Museum Victoria
The body length of the Black Rock Scorpion can be up to 55 mm and is normally dark brown, often appearing to be black. It lives in a cleared area beneath rocks or logs, and has a burrow that leads from this area to the outside. This is a relatively long-lived species; females may take over two years to reach maturity and survive for a further eight years.
The Black Rock Scorpion survives on a diet of other invertebrates, such as cockroaches, beetles, millipedes, centipedes, spiders and occasionally earthworms. Cannibalism has been observed amongst scorpions. Like most scorpions, the Black Rock Scorpion is a ‘sit and wait’ predator – it sits near the mouth of its burrow and detects passing prey by monitoring the substrate vibrations caused by the movement of the prey.
The sting of the Black Rock Scorpion can cause inflammation and pain for several hours, and medical advice should be sought.
Koch, LE 1977. The taxonomy, geographic distribution and evolutionary radiation of Australo-Papuan scorpions. Records of the Western Australian Museum 5(2):83–367.
Walker, K. L., Yen, A. L. and Milledge, G. A. 2003. Spiders and Scorpions commonly found in Victoria. Royal Society of Victoria: Melbourne.
That’s a very interesting question. The gestation period of scorpions varies widely between the different species, from 6 weeks to 18 months. To further confuse the issue as to whether your other scorpion is male, and putative father-to-be, some scorpion species can reproduce through parthenogenesis. Parthenogenesis is asexual reproduction. You can learn about reproduction in scorpions in this scientific paper.
This is a general guide - the best method is to turn the scorpion over with tweezers and look underneath. There is a v-shaped organ underneath called pectines, lined with comb-like teeth. At the centre of this v is an operculum. In males, the operculum is split and in females it is not.
In males, the pectines are large and the comb-like teeth long. In females, the pectines are much smaller and the teeth smaller as well. If you search YouTube for 'sexing black rock scorpions', there is footage showing exactly how to find the pectines and operculum.
Hi Rick - we ran this past our Live Exhibits team, who have supllied the follwing reply for your query:
Urodacus take about four years to reach adulthood, during which time an individual will moult five times. They are able to mate not long after maturing and the gestation period is about 18 months. The growth and development time is highly variable depending on temperature and food availability – in the wild scorpions may go without food for weeks or even months and their development slows correspondingly.
The book you refer to is available at http://thedailylink.com/thespiralburrow/index.html
Hi Lupe,We recommend that you contact the San Diego Natural History Museum for information about the scorpion you have found: http://www.sdnhm.org/
It is unusual for a scorpion to lie on its side. This behaviour is probably temporary but if it continues there may be something wrong with the scorpion. Check that the temperature and humidity is suitable for that species, and that it's not being overfed or fed contaminated prey.
Hi Rick, Black Rock Scorpions (Urodacus manicatus) do not particularly require light, but it is useful to give them an indication of the daily rhythm of night and day. A light can be also good as a heat source, as a heat mat or other subsurface heat source can negate the fact that scorpions burrow downwards to keep cool. The light should be a low wattage bulb, available from any lighting store. If you require more heat, a higher wattage red bulb will produce a higher temperature without producing any light visible to the scorpions.
Because the mother often doesn’t feed whilst carrying her babies around, she is hungry by the time they depart and will readily eat them if she comes across them in their enclosure. Even if there is lots of food available, the mother will eat them as readily as she would eat a passing cricket. So the best time to separate them is when they’ve darkened slightly after their moult.
Hi Beverley, the scorpion is most likely to be a Marbled Scorpion (Lychas marmoreus), which is pale to mid-brown, speckled with darker and lighter browns. They grow up to 3cm. The Black Rock Scorpion (Urodacus manicatus) is larger and darker. It grows up to 5.5cm and is a very dark brown with paler nippers. The Marbled Scorpion is very common on the Mornington Peninsula and frequently comes into houses, but they quickly desiccate and die in the dry environment inside a house. Both species can sting humans and animals, producing at most inflammation and pain for several hours. There are records of cats and dogs being stung, and the symptoms are similar to stings in humans. Because the scorpions live outside the house more than inside, pets are most likely to encounter them (particularly the curious ones) and stings are not uncommon. As a general rule, these scorpions are not a serious threat to cats, but if you have any doubts, please consult a veterinarian.
Hi everyone, to answer some of those questions that you all have! If you can keep them at a temperature of approximately 18-24 degrees that would be ideal. I’m not sure if you can easily alter the temperature in your air conditioned room i.e can you keep it around the 18-20 degree mark that would be fine. Any extreme temperature variations such as 40 degrees are likely to place stress on an animal which could result in losses. More so for the young. Alternatively if you don’t want to have your air conditioner running all the time you could possibly leave them where they are and if you know that an temperature extreme is approaching then transfer them into a room with a more constant temperature. In terms of the babies dying, i can understand if this is upsetting but sometimes losses do occur with the young. In terms of food, see if your pet food supplier can provide you with some pinhead crickets. Provided for them twice a week. These would be an ideal size for the baby Scorpions. Hopefully this is of some help. Feel free to contact us for further information.
Hi Brad, please read our reply to Carson on 11 February for advice on what type of enclosure you can use to accommodate multiple babies.
Tap water is fine. The babies only need a damp end of the enclosure as water source, no water dish required.
In terms of food frequency and size we usually feed our adult scorpions once a week. The basic rule of thumb in terms of size is a ¼ of the Scorpions body size. As an example we feed our adult Black Rock Scorpions 1 medium cricket per week. Baby Scorpions would get 1 pinhead cricket per twice week with size increasing as they get bigger and then eventually dropping back to once cricket a week once they are adults.
For your other questions, please see previously posted answers, and also check out Bugs Alive – A Guide to Keeping Australian Invertebrates.
Once the babies have left their mothers back they should be housed individually. This can be done using a tool box or what some people may know as a nuts and bolts style storage system, which can be purchased at hardware stores. The lid will need to have some air holes drilled into it for ventilation. The enclosure can have either a sand or coco-peat substrate(available in bricks from hardware stores).
For further detail, a good general guide on the care of scorpions is Bugs Alive – A Guide to Keeping Australian Invertebrates.
Once the babies have left their mothers back they should be housed individually. This can be done using a tool box or what some people may know as a nuts and bolts style storage system, which can be purchased at hardware stores. The lid will need to have some air holes drilled into it for ventilation.
We wouldn’t recommend inbreeding. If you would like a good general guide on the care of scorpions, try Bugs Alive – A Guide to Keeping Australian Invertebrates.
Hi Gemma, if your scorpions are still white but not being looked after by their mum it is not normal but it may still be fine. Remove all the other scorpions from the enclosure and give them some room to relax. After their first moult they would naturally disperse. At this time you can separate them from one another and start feeding them tiny food items such as pinhead crickets.
The Australian species of Black Rock Scorpion are not considered highly dangerous, but it is probably best if you avoid them and observe from a safe distance.
Hi Dicko, the first thing to try to work out is if you have males or female scorpions in your collection. By looking at the underside of the body you should be able to see a small disc above the pectines (comb like structures). If it is split it indicates that it is a male – if no split you have a female. Females tend to be a little bulkier as well. To work out if she is pregnant you need to watch her body shape – she will become rotund. If you believe she may be preparing to give birth you need to give her some ‘quiet time’ as scorpions will often become stressed and re-absorb their young if conditions are incorrect. Best of luck with your new pets!
Hi Ron - congratulations on your newly acquired pets! The behaviour you have described is called Stilting. It helps the scorpion to regulate it’s body temperature, thought to increase the air flow over its body. This can vary with the body only being a little off the substrate to an extreme vertical posture. High temperature and humidity can be a trigger but scorpions also show this behaviour in cooler temperatures. Gravid/ pregnant females tend to do this behaviour more coming up to giving birth which for this species is around March/ April. This is not saying she isn’t pregnant but if she is she would give birth next march/April. The Black rock Scorpions are commonly found throughout the Great Dividing Range in NSW and they live in specific micro-climates meaning they need a particular humidity, temperature and moisture level to stay healthy. So their behaviour may be them trying to settle into their new environment. There is a great book out called ‘A Guide to keeping Australian Scorpions in Captivity’ by Mark A. Newton.
Hi Harry, can you please explain what you mean by 'substance'? Are you referring to feeding your scorpion or housing your scorpion?
Hi Callum, it is thought that most Australian species of scorpion live between 2 and 10 years, although one commercially sold species lives to around 15 years. As to where to source scorpions, please have a read of our question of the week on this topic.
Hi Judy, the weight of a normal sized scorpion will depend on the species. Because there are many species of scorpions, each of them will have different physical characteristics. Most scorpions will weigh between possibly 50 gm (some say the heaviest is 60gm) and a few grams. Please see the following website for further information:
http://www.ntnu.no/ub/scorpion-files/faq.php http://www.sandiegozoo.org/animalbytes/t-scorpion.html http://www.centralfloridazoo.org/emperorscorpion
Hi Jesse, if you have a read of the posting that Discovery Centre made on the 11th of February, you will find information on how to care for young scorpions. Good Luck.
Hi Dave, scorpions have no interest in pets; if the scorpions are in the house they will be looking for small invertebrates to feed on. The dog may be stung if it stood on or started patting or playing with the scorpion. We are not aware of scorpion stings posing a serious threat to the welfare of pets, although it would be very painful.
Hi Sarah, don't be too concerned, scorpions can be common in Victoria including parts of Melbourne and its suburbs. They have no interest in people and stings are rare. Scorpions in Australia are not considered highly dangerous but if you were to be stung it wouldn't be a bad idea to go to your doctor as a precaution. I personally would let the scorpion go where you found it.
Hi there Cara. Sometimes these scorpions do come in looking for food of their own accord and it might be worthwhile putting draught excluders on the doors to prevent this. As indicated above the Australian Museum's scorpion fact sheet gives some interesting information on their habits, habitats, how to minimise them in your garden and avoid being stung. It says 'Australian scorpions can give a painful sting but are not considered dangerous. First aid for a sting is to apply a cold pack and to seek medical aid if pain persists. It is also a good idea to try to catch the scorpion and have it identified.' We have a free identification service at the museum, so feel free to send in your specimen.
Please have a look at the following links which feature a couple of the species found in Melbourne which also occur in South Australia. There may be other species found in Adelaide which do not occur in Melbourne. The South Australian Museum will have more expertise in scorpions from your region if your scorpion is not one of these 2 species.
Scorpions can be brought into homes under the bark of firewood or may wander in looking for prey.
Hi Irene. Scorpions generally do not enter houses of their own accord but usually come in accidently on wood or other things brought in from outdoors. If you have them in your garden you may find them in the house occasionally. Draught excluders along doors can help prevent further unwanted visitors if they are coming in of their own accord. The Australian Museum's scorpion fact sheet gives some interesting information on their habits, habitats and how to minimise them in your garden.
We love receiving comments, but can’t always respond.
we do not receive many enquiries at the Museum about Black Rock Scorpions coming into peoples' homes, as opposed to some of the other species which seem to wander into homes in greater numbers.
There are a number of species of scorpion in Southern Africa which may look superficially similar to Australian species. The link below is to an online science magazine about African scorpions complete with an e-mail address for the author. If you have collected the scorpions you may be able to take a digital image and send it to him to see if he can confirm if it is an African scorpion and obtain some further information about it.
Hi Sally, the Live Exhibits team at Melbourne Museum are responsible for the care of the live animals, here. They have advised that the babies usually stay with their mum for a few weeks, clinging onto her back and body. At this stage they are pale in colour and they won't need food or water themselves. You don't need to do anything differently to your scorpion during this stage, except minimise the amount of disturbance she receives. Some mother scorpions will eat their babies if disturbed too often. Once the young leave their mother and start to move around the enclosure on their own, they can be separated into individual enclosures. The young will be ready to feed by themselves when they reach this point but need tiny insects (about half their own size). You might find this book useful - it has a special page about keeping scorpions!
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