[LMB] Do the big Australian spiders survive in freezing climates?

Leanne Martin leanne_martinau at yahoo.com.au
Mon Jan 3 06:48:31 GMT 2011


Hi all,

A number of species survive quite well in freezing temperatures. As they 
(spiders) are not warm-blooded creatures they have a broad range of temperatures 
within which they will survive quite happily - depending on the species. I guess 
the real questions are:
a) Do whatever spiders feed on survive in freezing temperatures?  >>  Yes;
and
b) Does what feeds on spiders survive in freezing temperatures?  >>  Yes. 

Our most lethal and aggressive poisonous spider is a tunnel dweller - the 
Funnelweb - survives overwintering quite happily in its burrows. Its fangs are 
so strong they reportedly can pierce and adult male's large toenail and still 
deliver a fatal dose. As a species (really a large collection of subspecies) it 
is represented in one form or another from the tropical norther state of 
Queensland to the southern tip of the island state of Tasmania (our southern 
most and coldest state) with the desert country running down the middle of the 
country presenting a natural barrier. This spider has become a greater threat in 
New South Wales (where the most dangerous subspecies lives) because feral 
domestic cats have killed off their natural enemies, e.g. the Numbat - not 
directly related to the Wombat.

Just because the temperature drops below zero doesn't mean life stops - may go 
slower though...
Our sub-zero zones don't get there as quickly or stay there as long as they do 
in the northern hemisphere. The 2 main reasons for that are:

a) Our mountain rangers (calculated to be the worlds oldest) have long ago 
eroded from the heights of those of our northern cousins thereby not funneling 
to earth the freezing winds / snow / ice that go with those heights;
and
b) There are no continuous land masses between our Antarctic region to our 
continent, unlike the northern continents, thereby not funneling northward the 
massively freezing weather that our northern cousins get directed their way 
south from the Arctic. Also, because the Eurasian continents form such a 
contiguous land barrier to water currents the warmer currents that the southern 
continents enjoy are not reflected in the north.

>>Do the big Australian spiders survive in freezing climates?

>Freezing Climates? We  don't really have them. A cold mainland winter 
>occasionally has a day with a sub-zero high, but it is rare, and only 
i>n the south. A winters day in the north is usually about the mid 20s 
(> mid to high 60s F).
>
>Here in Melbourne, the most Southerly (1) mainland Capital, snow is 
>enough of a rarity that is hits the news if there is any, even a 
>couple of minutes fall. We have the "Snow Fields", but it is a tiny 
>percentage of the smallest state.
>We have multiple 40+ (100+) days every year, and the low days tend 
>only to be ones where the days stay cold from an overnight low.
>
>Where temperature variance in a given day is usually about 15 (27) 
>degrees during the day, and has been known to be as much as twice 
>that, with a 20 (36) degree drop in an hour, the micro-climate 
>requires unusual circumstances to have a "very cold"  day.
>
>Iestyn

>(1) Furthest from the equator.



      


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