australia:snakes
Australian snakes
Introduction
most of the world's top 10 venomous snakes reside in Australia!
snakes in Australia are a protected species!
the venomous snakes are Elapids of which there are 90 terrestrial species which account for 57% of all terrestrial species in Australia, and the non-venomous pythons
1)
Australian is home to over 130 species of the 320+ known species of Elapid snakes (including sea snakes)
all Australians and travelers to the Australian bush or coastal regions should know how to avoid and how to survive a snake bite.
snakes eat frogs, eggs, small mammals, lizards and even other snakes
snakes are active when their body temperatures are between 28 and 31 °C and thus they thermoregulate by basking in warm sunny spots in the cool early morning (eg. on your pathway) and rest in shade in the middle of hot days, and may reduce their activity in hot dry weather in late summer and autumn
the only time two snakes are in the same place is during courtship and mating. Otherwise the larger snake will usually kill and eat the smaller one
snakes can hear low pitch sounds and feel vibrations but have trouble hearing higher pitched sounds
snakes generally will try to make their way to their preferred escape route and last known safe haven, but sometimes they make poor choices when threatened and the eye sight is relatively poor - if a human is between them and their safe haven they may adopt a defensive raised posture to try to signal to you to get out of their way and then they will approach their safe haven which may appear they are chasing you but they are not!
if you approach and harass them they respond with a strike and a bite, although, fortunately, most are dry bites which do not envenomate - never try to catch a snake unless you are trained to do so - call a snake catcher!
snakes like to hide under shelters such as sheets of iron roofing, concrete slabs, piles of wood or rocks, etc - take great care when lifting these up.
Evolution
snakes evolved from lizards c120-150mya
Pythons (lay eggs, have a pelvic remnant, two lungs, and did not make it to America until recently) diverged from Boa (give birth to live young) in the Cretaceous period and migrated from Asia to Australia and New Guinea via
Wallacea c8-14mya
ancestors of
Morelia split from the Python tree c35mya
2)
Elapids (including sea snakes) appear to have evolved from an Asian ancestor 38mya and then rapidly diversified into:
all continents became colonised with snakes by 30-25mya
it would seem the Australian elapids are all fairly closely related to each other as a relatively snake-free Australian continent was colonised only 25 mya
3)
morphological and biochemical data have suggested a close relationship between Australian terrestrial proteroglyphs and hydrophiid sea snakes
prey preference drives the evolution of venom composition and toxicity in snakes
-
Victorian snakes
Tiger snake
Notechis sp
17% of snakebites in Australia
these are also the main snakes living in Tasmania (where a sub species, the Black Tiger snake also resides)
relatively poor eyesight and slower moving than a brown and thus more likely to be trodden upon
in Victoria, the species is the Mainland Tiger Snake (Notechis scutatis) which usually grows to 0.9m but can grow to 2m and prefers coastal areas and wetlands
these snakes flatten their body and raise their heads if threatened
Common Eastern Brown snake
Pseudonaja textilis - a fast (can outpace a human running) and aggressive snake with good eyesight
the second-most venomous terrestrial snake in the world
grows to 1.5m and sometimes to 2m
found along the east coast of Australia from Malanda in Qld down to Victoria and across to Yorke Peninsula in Sth Australia. Disjunct populations occur elsewhere such as NT.
tends to prefer drier areas such as sclerophyll forests, coastal heaths, farmlands (especially as they prefer to eat rodents), etc
has two phases of threat display:
partial: raises front of body partly off the ground and flattens neck
full: rises up vertically high off the ground, coiling its neck into an S shape, and opening its mouth
this means, unlike most other snakes, these snakes can bite the upper thigh when standing, but fortunately most bites do not result in envenomation
walking in undisturbed areas on cool days in September and October risks running into courting male snakes, that would not notice people until close as they were preoccupied with mating
snakes will generally move away early when they detect humans, and they can detect them better if they are wearing dark clothing and approaching quickly and noisily, and are less able to detect when people are moving slowly, especially on a cloudy, windy day
Red-bellied Black snake
Pseudechis porphyriacus “false viper”
native to the east coast of Australia as far north as Gladstone in Qld
in Victoria it is mainly in the south, east, central parts of Victoria but extends to Sth Australia along the Murray River
account for 16% of snake bites in Australia but no deaths
it is the most commonly reported species responsible for envenomed dogs in NSW
not aggressive, less venomous, usually within 100m of a water body, average length 1.25m but can grow to 2.5m
there are related species in the Atherton Tablelands in Qld (Pseudechis porphyriacus eipperi ) and another in southeastern South Australia (Pseudechis porphyriacus rentoni )
Copperhead snake
a shy snake which rarely bite humans unless provoked
Common Lowlands Copperhead Australeps superbus
length usually reaches 1.75m
common in southern Victoria and in Tasmania
these are the only snakes on Philip Island
Alpine or Highlands Copperhead Australeps ramsayi
Pygmy Copperhead Australeps labialis
non-venomous pythons
mainly found in the Wangaratta and eastern Gippsland regions
Carpet Python Morelia spilota metcalfei - mainly nocturnal; northern areas;
Diamond Python Morelia spilota spilota - non-venomous; coastal heaths of far east Gippsland
other snakes
Little Whip snake Rhinoplocephalus flagellum
snakes confined mainly to north-western regions of Victoria (eg. Mallee):
Western Brown Snake Pseudonaja nuchalis - fast, aggressive
Master's snake Drysdalia mastersii - mainly Mallee
Mitchell's Short-tailed snake Rhinoplocephalus nigriceps - mainly Mallee & north-central areas
Bardick Echiopsis curta - mallee region
Port Lincoln snake Rhinoplocephalus spectabilis
Red naped snake Furina diadema - rare; usually assoc. with termite mounds
Yellow-faced Whipsnake Demansia psammophis - fast snake; Murray River;
snakes confined mainly to northern Victoria:
Curl Snake Suta Suta - mainly in the Loddon, Avoca and Murray rivers region
Bandy Bandy snake Vermicella annulata - rarely seen snake in northern areas; nocturnal;
Blind snakes Ramphotyphlops spp - rarely seen snake in northern areas; non-venomous; nocturnal;
snakes confined mainly to south-eastern Victoria:
australia/snakes.txt · Last modified: 2019/02/12 01:01 by gary1