Nature Stuff mdavid.com.au

What is a spider?

Most people think they know the answer to this question, but when challenged they usually say more about what a spider is not. Like, it’s not an insect, or not what you want to find in your lunch. So here’s my attempt to say what a spider really is.

Golden Orb Weaver

Yep, that’s a spider. Or more specifically, a Golden Orb Weaver (Nephila ornata)

A spider is an eight-legged critter that eats other critters. Where the term ’spineless’ is considered a bit of an insult for humans, among spiders it invites a sense of belonging because they don’t have a spine at all. Instead, they carry their squishy bits around inside a hard armour-like skin called an exoskeleton.

Now, apart from the bit about having eight legs I could have been describing a lot of other critters, including several insects here, so I’ll now mention some more things that make them different from insects.

The differences between and insect and a spider

You’ll see in the cartoony pictures above that the spider doesn’t have wings. That means spiders can’t fly, although some of them do manage tricks which allow them to either glide or be carried by the wind. You’ll also see that the insect has its body divided into three main bits (head, thorax and abdomen) while the spider has only two bits. That’s because the spider’s head and thorax are combined into one section called a cephalothorax.

Red Velvet Mite

Not a spider: This little critter has eight legs like a spider, but it’s not a spider. My guess is it’s a Red Velvet Mite. This one was about 3 mm long. Mites are closely related to spiders.

And here’s another thing about spiders: they’re not able to chew their food.

Wolf Spider shedding its skin

Wolf Spider shedding its old skin

Outgrowing their skins

I mentioned earlier that spiders wear a tough skin called an exoskeleton to hold their soft bits together. That system works well for spiders but it has its limitations too. The exoskeleton is not able to keep expanding as the spider inside it gets bigger. So as a spider grows up it sometimes has to produce another skin and shed the old one. The picture at right shows the discarded skin of a Huntsman spider.

Discarded spider skins are more interesting than most people realise. If you look at the close-up picture alongside it you’ll see it’s covered with lots of stuff like hairs and spines. So the spider sheds a lot of stuff with that skin. Of course I made sure there wasn’t a spider wearing the skin before I picked it up. When you see the size of its fangs you’ll understand why.

The bits that bite

Spiders have fangs which can inject venom. Despite that fact, most spiders are not dangerous to people. However, because some spiders can be dangerous I advise people to treat all spiders with caution, especially if you have trouble knowing which ones are the most venomous.

Venomous or poisonous?

You might have noticed that I said that spiders inject venom from their fangs. That’s why spiders are described as venomous instead of poisonous.

Now I could get into a bit of trouble here because this subject is complicated, but a rough guide goes something like this: something is considered poisonous if it’s dangerous to eat it. For example, many types of wild mushrooms are poisonous.

And a critter is considered venomous if it puts venom into you by either biting or stinging.

People need nature more than nature needs people
Nature Stuff

So what’s with this Nature Stuff then?

Birds

Indian Mynas
Pushy and invasive

Noisy Miners
Aggression in the suburbs

Noisy Miners, Indian Mynas
Here’s how to tell the difference

Starlings
Another feral pest, or not?

Australian White Ibis
Conservation takes a twist

Common water birds around Sydney

Masked Lawpings
Or should we be calling them Spur-winged Plovers?

Pacific Black Ducks
A common Aussie duck

Geese teeth
No seriously, do birds have teeth?

Birds’ knees
Do they bend forwards or backwards?

Rainbow Lorikeets
Raucous and colourful

Sulphur-crested Cockatoos
Beautiful birds with an awful call

Yellow-tailed Black Cockatoos
Beautiful birds with a beautiful call

Glossy Black Cockatoos
Casuarinas’ seed crackers

Are they Crows or Ravens in Sydney?
Here’s your answer.

Black Swans
Bird emblem of Western Australia

Brush Turkeys
Cool birds, huge nests

Darters
Comfortable on land, in the air and water

Australian Pelicans
An impressive large water bird

Black and white birds
Identifying from a bunch that is easily confused

The Australian Magpie
Buddies in the back yard

 

Reptiles

Lizard bite
Getting more than you bargained for

Asian House Geckos
More than just a pretty face?

 

Plants

Lantana
Tough, invasive and widespread

A few big Australian trees
Some examples I’ve seen in my travels

Unusual and beautiful Australian trees
Some more lovely trees

Why Australia’s giant trees might never return
Perhaps we shouldn’t take them for granted.

Insects and spiders

One of the longest insects in the world
(Including photos of course)

Jumper Ants and Bulldog Ants
Insects with attitude

Some common Australian orb-weaving spiders
A basic guide to their identification.

Hunstman Spiders
A spider with an undeserved bad reputation

Fear of Huntsman Spiders
How I dealt with it

Golden Orb Weaver Spiders
A common large spider

How many eyes do spiders have?
Here’s your answer (and photos).

newHow long do spiders live?
They can’t last forever.

How many eyes do insects have?
The answer might surprise you.

How I catch spiders
(to take them outside)

The amazing net-casting spiders
A bit of a favourite spider of mine.

Commensal spiders
Eating the leftovers

What is a spider?
No, seriously, what makes a spider a spider?

Jumping spiders
Cute and often colourful

 

Nature words

So what’s a feral species, really?
Here’s the real answer.

What’s the real meaning of the word ‘bug’?
Another one of those words with a very specific meaning.

Venomous or poisonous
What’s the difference?

 

Other stuff

From Cane Toads to tree frogs
It was rewarding in ways we didn’t expect

Book review
Back from the Brink

Camouflaged critters
Blending in to a scene near you

Critters in the city
Blending in to a metropolis near you

Fire and the Australian bush
A brief look at a complicated story

Cute stuff
Critters sure can look cute when they’re little

Feeding wild animals
Is it always a good idea?

Photo Sales
I might have that Australian nature pic you’re looking for

The Latest Pics
Archive of my latest nature photos


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