New Zealand - Monday, September 29, 2014 21:41 - 0 Comments
SNAKE SEARCH OFFICIAL REPORT
Last issue Investigate broke the story that New Zealand has an undetected colony of venomous Australian Copperhead snakes in the remote wilderness of abandoned South Island gold mines. This was after a prospector and geologist encountered one on the West Coast. The Ministry for Primary Industry’s official report, just released to Investigate, concludes the land would be ideal for snakes and the South Island could be home to about 100. The only problem? No one else has seen them. This is the full report by herpetologist DYLAN VAN WINKEL of consultancy firm Bioresearches:
In 1990, while prospecting for gold beyond Nelson Creek (42° 24′ 50.59″ S; 171° 33′ 42.11″ E) in the Grey Valley, West Coast, a “greenish brown, 30-inch long” snake was observed coiling up the arm of one of the prospectors. The notifier reportedly flung the snake off his arm and down a sluice face to rocks below.
The notifier subsequently identified the snake as a Victorian copperhead (Austrelaps superbus) from comparative photographs of Australian species. Further correspondence with local West Coast gold miners and a scientist at Landcare Research lead to the suggestion that a colony of snakes could be present in the West Coast gold mining districts. It was also suggested that the snakes may have entered the country during the gold rush period of the 1860s and 70s, when thousands of miners emigrated from the Victorian goldfields to the West Coast. Any snakes that may have stowed away in miner’s crates and equipment on sailing vessels could have freely entered New Zealand, via ports at Charleston, Hokitika, Greymouth and Westport, given the absence of biosecurity inspections.
The following report provides information on the ecology of Austrelaps spp., and assesses both the probability of establishment and potential risks to native fauna if establishment of an Austrelaps sp. were successful in New Zealand.
Aspects of Austrelaps Ecology and Life Cycle
The genus Austrelaps Worrell 1963 (commonly referred to as Australian copperheads) is represented by three species, including the pygmy copperhead (Austrelaps labialis; c. 80 cm, up to 120 cm), highland copperhead (A. ramsayi; c. 1.3 m, up to 1.7 m), and the lowland or southern copperhead (A. superbus; c. 1.3 m, up to 1.7 m). The three species are distinguished from each other based on head scalation, length, and distribution (Cogger 2014).
The genus is confined to south-eastern Australia, including the islands of Bass Strait and Tasmania (approximate latitudinal range from c. 30°S to 43°S), and occurs across a wide altitudinal range (sea-level to c. 1000 m) and wide range of climate regimes (e.g. temperatures range between c. -2°C to 41°C throughout their natural distribution).
Austrelaps spp. inhabit a broad range of habitats, from coastal sand dunes to grasslands to riparian margins, open forest and alpine tussocks; preferentially selecting sites near to water or marshes/ wetlands. Austrelaps spp. are both diurnally and nocturnally active, and have the ability to remain active at temperatures below 10°C. They feed principally on ectothermic vertebrates, especially frogs, lizards and small snakes; however, they are known to prey on invertebrates (e.g. grasshoppers), small mammals and birds.
Austrelaps spp. (particularly A. superbus) are well adapted to cool and temperate climates, and all species employ an ovoviviparous reproductive strategy (i.e. development of embryos inside eggs that are retained within the females’ body until they are ready to hatch. Young are then birthed live). Mating occurs in late summer/ early autumn, and females give birth to litters of 3 – 32 young the following mid- to late-summer; after a winter quiescence period (Shine 1987). Reproduction may not occur each year.
Little information is available on the movement or dispersal rates of Austrelaps spp.; however, Shine (1979) suggested that gravid female A. superbus are generally sedentary, yet males may move more extensively. Austrelaps spp. are mostly terrestrial (ground dwelling) rather than arboreal (tree dwelling), but are known to climb trees occasionally.
Copperheads are notoriously secretive and inoffensive, preferring to avoid encounters with humans where possible. This significantly lowers the probability of close human interactions and as a result, snakebites from this species in Australia are relatively uncommon. Continued provocation will certainly result in defense behaviours such as body flattening, hissing and violent striking, in an attempt to bite. The venom is strongly neurotoxic, but is also powerfully haemolytic [destroys red blood cells] and cytolytic [induces tissue death and gangrene] (Cogger 2014).
Potential Threat to New Zealand
Austrelaps suberbus is a generalist with regard to habitat and prey selection, and is tolerant of cool to cold, wet climates within its natural range. These characteristics suggest that it is certainly possible for this species to survive and reproduce successfully on the West Coast, as well as in many other regions of New ZealandWOULD YOU LIKE TO READ MORE OF THIS STORY?
You have clicked on subscriber-only content. You’d be surprised at just how much of this site you cannot currently see. If you’d like a peek, get a one day access pass for US$4.99, or choose one of our other subscription plans. Membership begins at just US$5.99 a month or $39.99 for the year
If you are an existing print subscriber you qualify for free access. Login to the site with your username and password using the Log In link in the upper right column. If you still cannot see protected content and you have a current print subscription, contact us via email for instructions.
- Editorial – Oct/Nov 2014 Investigate
- Compulsory Buddhism in schools
- The smacking debate
- ISIS – air strikes won’t do it
- Why Auckland’s draft unitary plan is daft
- NSA spies on Kiwis – journalist
- More Dirty Politics – Greens accused of lying about NZ dairy industry
- NZ First calls for halt to aerial 1080 drops
- Kauri dieback not as widespread as feared
- Britain on high alert over ISIS threat
- Hospital pays $190 million in damages
- NZ reacts to Russian troop movements
- Judith Collins forced to resign – the fallout
- The banal political correctness of social media
- Dissecting the Ebola virus – one of the riskiest jobs in the world
- Cyberattacks – the stuff you don’t know about
- ISIS in Syria: where to from here?
- The Flying Droner Service
- Kim Dotcom’s links to Nicky Hager Dirty Politics book revealed in text messages
- Breaking news – did Nicky Hager breach basic journalism standards in new Dirty Politics book?
- Actor Robin Williams found dead
- Transmission Gully greenlighted
- New Winston Peters book highly entertaining
- Gingko biloba and the Tebonin extract – Tree of Life?
- This morally and politically derelict government shames us – Amy Brooke
- Goodnight Malaysian…
- Blinded by the light – eco bulbs and smartphone screens a major sight risk
- Climate of fear
- Reaching out
- Book reviews – August 2014
- Lies, damned lies, and smart meters
- Memo to David Cunliffe – stop apologising, man!
- Separtists shot down MH17, shocked to discover it was civilian
- Australia: MH17 an ‘unspeakable crime’
- One law to rule us
- The asteroid strike that caused NZ mega-tsunami – RadioLive at 10pm
- Deep sea yacht rescue saves three in massive storm
- Snakes on a drain – ‘snake free’ NZ found to have Aussie serpents
- Big cats loose in NZ, the Goodnight Malaysian 370 book, the Mallard Moa hunt and more