Why is a slow worm NOT a snake?

[Goatboy]

Apologies if this is a daft question.

Wildlife presenters seem to love explaining to us that the slow worms are not snakes but are in fact legless lizards. Yet never seem to explain the difference.


So my question is what IS the difference between a legless lizard and a snake. I know lizards have eyelids and snakes don't but surely there are other differences? How do scientists define between the two?

[The Black Rabbit]

Not a daft question at all Goatboy. (Thats the BEST avatar on here by the way).

As far as I was aware, Slow worms:

Can shed their tails like other lizards when evading predators.(Snakes don't)

They have a partially forked tongue which unlike snakes, cannot protrude out of the mouth.

They are MUCH less flexible in terms of bending their body, than say a grass snake or adder (or smooth snake).

Their heads are the same width as their body (or no wider, anyway) (a good method of ID that).

(and the eyelids bit you mentioned).

Does not that help at all?

Doug

[Paul mabbott]

Pygopodidae - Wikipedia, the free encyclopedia
It all goes back a long way in evolutionsry history!

[Goatboy]

That is very helpful Doug, thanks.

I have just read that legless lizards have lost their legs over the centuries through evolution. It would be interesting to know if this happened later than the evolutionary split between snakes and lizards (I'm assuming that they are derived from the same primitive reptiles, may be wrong)

I think I'll doing a bit more research....

[Meta menardi]

This is one of those questions that at first make you go "Doohhhh", then when you think about it, my level of understanding is about "well, because someone told me so".

I think what you want is a cladogram, which shows where things branch, in the way you ask about losing legs and when it happened.

Cladistics - Wikipedia, the free encyclopedia

is a link to the basics of cladistics.

Araneomorphae

is a link to the stuff I am most familiar with, Spiders.

I have not looked for a cladogram for reptiles on TOL (Tree of Life), but it could be there.

Hope this helps or at least provides some interest.

[Ukwildlifeo]

Originally Posted by The Black Rabbit

They have a partially forked tongue which unlike snakes, cannot protrude out of the mouth.

Ive read that too, but look at this:


maybe someone forgot to tell her! I think maybe its that lizards don't protrude there tongue to 'smell the air' like snakes do and somewhere in the literature some wires crossed

[The Black Rabbit]

Originally Posted by Ukwildlifeo

Ive read that too, but look at this:


maybe someone forgot to tell her! I think maybe its that lizards don't protrude there tongue to 'smell the air' like snakes do and somewhere in the literature some wires crossed

Maybe thats true.

And Meta menardi - I thought that God made the Snakes and God made the Slow worms at the same time - on the "Sixth day" to be precise...

Doug

[Ukwildlifeo]

Originally Posted by The Black Rabbit

Maybe thats true.

And Meta menardi - I thought that God made the Snakes and God made the Slow worms at the same time - on the "Sixth day" to be precise...

Doug

Dont be silly. Snakes are the work of satan, and slowworms are one of gods creatures.

As for evolution of snakes there were around in the Cretaceous period, so where around with the dinosaurs and evolved from lizards or atleast the same related group. The fossil record is poor though, as snakes ahve small fragile bones.

[Meta menardi]

Originally Posted by Ukwildlifeo

Dont be silly. Snakes are the work of satan, and slowworms are one of gods creatures.

As for evolution of snakes there were around in the Cretaceous period, so where around with the dinosaurs and evolved from lizards or atleast the same related group. The fossil record is poor though, as snakes ahve small fragile bones.

Whoever. Certainly better than I can do. I have to say, having spent quite some time logging snakes (mainly Adders, Grass snakes seem to be getting very localised), and Slowworms too, I would love to see the Smooth snake. I will have to move house. Better range of Spiders down South too.

I do love the gold of a slowworm, but the pattern of an Adder is so numinous, it calls to a real memory of pattern in a wild landscape.

[Paul mabbott]

Originally Posted by Meta menardi

........ logging snakes (mainly Adders, Grass snakes seem to be getting very localised), and Slowworms too, I would love to see the Smooth snake. I will have to move house. Better range of Spiders down South too. ............

On the other hand wait a few years for enhanced localised global warming and the south may be a desert ... might be a better gamble to sit and wait for the dry heaths to reach you?