Saturday, 21 February 2015

Local 'blueys"

Rather freakishly, I'd almost completed this post on blue-tongues when I noticed that just the day before a good friend of mine and fellow blogger here in Canberra had posted similarly on these lizards (see here). What would be the chances? Oh well - having put the effort in I'll just post mine as well anyway...

Canberra seems to have experienced somewhat of an influx of blue-tongued lizards this year (aka blue-tongues or just 'blueys'). Strictly I suppose it was an increase in numbers following good breeding success and survival, rather than an influx which suggests they'd come from elsewhere. Maybe I could claim I mean an influx to Canberra's suburbs from the various nature reserves that surround and ramify through this "Bush Capital" city.

Whatever, there have been a lot more of them around, with lots of reports of them from friends and in the media, and very sadly, several seen squashed on our roads. I don't know the reasons for this increase, other than the likelihood that it is simply the result of several years of good rainfall, leading to easier conditions for them.

But certainly, it has been wonderful to see them around, particularly as a few have ventured into our garden on occasion, though the preponderance of cats in our neighbourhood means they haven't stayed around for more than a day or two. We've had them show up in previous years, but there have been more this season. 

Eastern blue-tongue on the paving outside our front door in Canberra (Nov 2011). 

After being disturbed, it did it's huff and bluff routine before disappearing into the azaleas.

It brings back happy childhood memories as a young kid in Sydney's Northern Beaches suburb of Elanora Heights, when we had wild blueys living in the storm-water drains and rockeries in the backyard, but I also had several of them as pets in a huge 'blue-tongue pit' we'd dug in a corner of the garden. Completely ethically and legally bankrupt by today's standards, these had been caught in bushland as I walked a rather round-about way home from school. I can't recall all their names, but the first was predictably "Bluey", and there was a "Lizzie", as well as Shad and Grunk named after the neanderthalesque couple from a kid's TV show called "It's about Time".

Bluey must have been pregnant when I found her, because not much later she gave birth to five incredibly cute miniature replicas, each about 10 cm long (unusual for reptiles, blue-tongues have live young rather than laying eggs). 

I used to feed them on minced meat,egg, snails, banana and dandelions. Even today, when a bluey ventures into the garden and I bother to catch it, I'll give it a bit of banana in gratitude. And despite their huff and puff of disapproval at being picked up, they always hoe into the peace offering. 

The Canberra blue-tongues are generally much more yellow-brown than the silver-grey of the ones I knew in Sydney.

Eastern blue-tongue in the rocks beside the pool at our home in Kambah, Canberra (Oct 2013).

This eastern blue-tongue was at the eastern end of The Coorong in South Australia (Oct 2008).

So far, this has all been about the 'eastern blue-tongue', more formally known these days as the Eastern Blue-tongued Skink Tiliqua scincoides. The name clearly indicates it is a skink (i.e. in the reptile Family Scincidae), albeit a very large and robust one compared to most other family members. But this is just one of six species of the genus that occur in Australia, and there are another two in Indonesia/West Irian. A further two of Australia's six also occur in the ACT - T. nigrolutea, the Blotched Blue-tongued Skink, and T. rugosa, the Shingleback (also known variously and regionally as either stumpy-tail or stump-tailed lizard or skink, bobtail, sleepy lizard, and pinecone lizard).

The Blotched blue-tongue inhabits the higher ranges of the ACT and is not uncommonly seen basking on roads in the mountains on sunny days. They are much more attractive than the name suggests, with tones of silver-white and pink-orange amongst the dark greys and browns, especially during the breeding season. I reckon some of the patterning is reminiscent of the pattern and colour of the granite outcrops that characterise much of the Brindabellas and high peaks of the ACT. 

Blotched blue-tongue on the road in Orroral Valley, ACT (Oct 2008).

Blotched blue-tongue on Corin Road, ACT (Feb 2015).

This one had much brighter colours than the Orroral Valley one.

When removed from the road and placed amongst the gravel and roadside grasses the camouflaging colour scheme came into its own.

And it remained extraordinarily placid throughout, even when picked up.

No blue-tongue is particularly agile or fast on its (relatively tiny) feet. I guess they have little need to evade predators, which they tend to try to deter more with their huff and bluff display, and flashing blue tongue. But honestly, the blotched blue-tongue takes indifference to extremes. I've always been able to walk straight up to them and pick them up off the road (as much to keep them from being a casualty to passing cars as to "commune" with them briefly) without even a flinch on their part. And on release they just sit there, no flurry of escape, just a resumption of apparent lethargy and apathy. 

The Shingleback, on the other hand, is relatively feisty and is restricted to lower elevations. It is at the edge of its extensive (southern and inland eastern Australian) range in the woodlands of Canberra's north-eastern fringes, and is most commonly seen in woodland reserves like Campbell Park and Mulligans Flat. 

Surprisingly, I couldn't find any photos that I'd taken of Shinglebacks in the ACT so I'll have to use some from further afield. But these highlight the differences in colour and pattern that also occur in this species. In my experience, they seem in general to be darker in the east and lighter and more patterned as you head west. The species is divided into four subspecies but I don't think there is necessarily a strong correlation with overall outward appearance (T. r. aspera is the 'eastern shingleback', rugosa is the 'common shingleback', and there are two geographically restricted subspecies in Western Australia, T. r. konowi on Rottnest Island and T. r. palarra around Shark Bay).

Shingleback threatening me as I went to remove it from its risky position in the middle of the road.
Allena, central-west NSW, Oct 2014. (see earlier post)

All-dark Shingleback near Ivanhoe, western NSW (Sep 2008).

They're very charismatic creatures in a dull, sedate kind of way.

This and the following photo are of a pair of Shinglebacks in Kinchega National Park, western NSW (Oct 2008).

The patterning of yellow ventral scales is only slightly different on this one, and the tail is more pointed.

This Shingleback, at the eastern end of The Coorong in South Australia, is more highly patterned, and in this particular sandy situation, is better camouflaged. (Oct 2008).

And this Shingleback from near Manypeaks in south-western Western Australia (Sep 2004) shows the slight banding pattern characteristic of the western populations of the species.

I always love coming across blue-tongues when out travelling. Great lizards.

Sunday, 15 February 2015

Narooma Hermits

The first weekend of February, after school had resumed and the crowds at the coast had mostly dispersed, we had a family long weekend at Narooma, on the New South Wales south coast. Narooma is a coastal town of 8,500 people and is situated between the surf beaches to the east and Wagonga Inlet which stretches westwards into the hills. The main body of Wagonga Inlet is connected to the ocean by a strongly tidal channel that at low tide has some extensive patches of sand/mud flats which are good for shorebirds. It's a lovely place, in an idyllic location, and I've been there quite a few times. It's also the launching place to go to Montague Island, some 7 km offshore, where I've been several times to participate in shearwater surveys.

On this occasion we stayed in a cabin at the caravan park on the ocean beach rather than at the Big 4 on the inlet. Our getting up early on the first morning was rewarded with a truly magnificent sunrise.

Sunrise over Montague Island, NSW  (7 Feb 2015)

Glasshouse Rocks sunrise, Narooma, NSW  (7 Feb 2015)

I could put up 100 more sunrise photos, all different, but this post is about hermit crabs - the biggest I've ever seen. I've seen plenty of hermit crabs in various places, mostly in warmer waters than the NSW south coast, but they have generally been fairly small and I haven't tended to try to photograph them. One exception was a cute little guy James and I found at Woody Head (Bundjalung National Park) near Iluka in northern NSW in 2007...

A hermit crab from Woody Head on the the north coast of NSW, July 2007.
Possibly a species of Dardanus, Family Diogenidae?

These Narooma ones, however, were huge. They were exposed at low tide right in the muckiest corner of the Narooma boat harbour, still just catching the late afternoon sunlight, and were within a few metres of the harbour wall. They were quite accessible if you were prepared to jump the two metre drop and squelch about the rocks, and oysters. 

There were at least a dozen or so of them visible in this little muddy corner and I ended up with photos of eight of them. It seems they are Stridulating Hermit Crabs Strigopagurus strigimanus

#1 Stridulating Hermit Crab Strigopogurus strigimanus - Narooma NSW, 7 Feb 2015

#2 Stridulating Hermit Crab Strigopogurus strigimanus - Narooma NSW, 7 Feb 2015
#3 Stridulating Hermit Crab Strigopogurus strigimanus - Narooma NSW, 7 Feb 2015

#4 Stridulating Hermit Crab Strigopogurus strigimanus - Narooma NSW, 7 Feb 2015

#5 Stridulating Hermit Crab Strigopogurus strigimanus - Narooma NSW, 7 Feb 2015

#6 Stridulating Hermit Crab Strigopogurus strigimanus - Narooma NSW, 7 Feb 2015

#7 Stridulating Hermit Crab Strigopogurus strigimanus - Narooma NSW, 7 Feb 2015

#8 Stridulating Hermit Crab Strigopogurus strigimanus - Narooma NSW, 7 Feb 2015

It wasn't until I was cropping the photos for this post that I realised some of the white spotting on crab #8 was in fact several small goose-barnacles attached to its legs. A variety of marine encrustations on the shells is expected, but I wonder if the crab is aware of these goose-barnacles and what impact they might have if they grow larger. I assume they are out of reach of the crab's powerful nippers. 

My understanding is that hermit crabs will use whatever shells are available to them that are of appropriate size (and are vacant!). Given the size of these crabs, I'm surprised there are enough large shells to go around. I don't know a lot about shells, but the ones used by these crabs appear to be some species of large spindle or tulip shell (Family Fasciolariidae), possibly Pleuroploca australasia. The hermit crab from Woody Head in the first of these hermit crab photos is using a species of triton from the Family Ranellidae.

Stridulating Hermit Crab #8 has a crop of small goose-barnacles growing on its legs.

Stridulating Hermit crabs grow to a length of 130 mm. They eat both plant and animal matter, including shellfish, and are found from shallow coastal waters to depths of 200 m around the southern Australian coast (from Bunbury WA to Sydney NSW). One reference (Edgar,2000) says they are common on shallow Tasmanian Reefs but uncommon in diveable depths around the mainland. I don't think these crabs have read that book! 

They're called stridulating hermit crabs because they can produce a noise by flexing and extending parts of their claws, supposedly to scare off predators and deter other crabs from encroaching on their patch. 

This would presumably explain their scientific name, Strigopogurus strigimanus, which means "furrow-handed furrow-crab" [striga: Latin - ridge, furrow or groove; pogouros: Greek - crab; and manus: Latin - hand], the ridging of the claws enabling the stridulation noise to be made.

There are two families of hermit crabs - the Paguridae and the Diogenidae. The latter are also sometimes called the left-handed hermit crabs because the left chela or claw is usually enlarged (rather than the right as in other hermit crabs). The stridualting hermit crab is one of the 430 or so species of Diogenidae worldwide.

As far as I can deduce, Strigopogurus strigimanus was first collected from Tasmanian waters by someone called Gunn in 1838 while on the 'Voyage of H.M.S. Erebus & Terror, under the command of Captain Sir James Clark Ross, R.N., F.R.S., during the years 1839 to 1843'. It was described and named several years later (in 1847), by Adam White, as Pagurus strigimanus, based on the specimen by then housed at the British Museum. 

Adam White was an assistant at the Zoology Branch of the Natural History Division of the
British Museum for 28 years from 1835. He left a prodigious scientific output, including many works on crustacea. 


Australian Marine Life - The Plants and Animals of Temperate Waters. Graham J. Edgar, 2000. Reed New Holland, Sydney.

Seashells of South-East Australia. Patty Jansen, 2000. Capricornia Publications, Sydney.

A Handbook to Australian Seashells - On Seashores East to West and North to South. Barry Wilson, 2002. Reed New Holland, Sydney.