That rusty sheet of metal is looking at you… Could it have a lizard under it? Maybe even a snake? Unable to hold yourself back anymore you go over and lift it up, the plants growing at its edges bow backward, and underneath scores of tiny invertebrate’s squirm away into the damp mud. Then you spot
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A handsome male Slow Worm emerging from hibernation in mid-March. |
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A male (right) and a female (left) basking together beneath a sheet of old metal. |
Finding one of these beauties is like finding buried treasure, and these legless lizards are beautiful as they are scaly. Whenever you find one lounging under a stray piece of metal, you’ll get a little rush, something I’ve felt countless times, I think it’s just because they’re so different compared to things like birds. And (one of) the great things about Slow Worms is they don’t mind living with humans. This probably has something to do with the fact they spend most of their time underground, where they don’t really see or have to tolerate many of us. Either way, especially if you live near the South Coast, chances are there are some right on your doorstep.
Go on! Give it a lift, never know what could be underneath it. |
In this blog post, I’ve noted down the markings and signs to look for that tell you the gender of that polished little lizard in front of you. And remember, just like it says in all the textbooks “they aren’t snakes, they’re legless lizards”.
Characteristics of a male Slow Worm:
The most immediately obvious sign to look for is the colour of the Slow Worm. While occasionally difficult to distinguish gender based on this, the males are always a beige/tan to a sickly grey colour all over the body, which is relatively pale. If you (CAREFULLY) pick up the Slow Worm, you can also look underneath at the colour of its belly. If it’s a male it’ll have a beautiful gray one with a silver sheen,
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My home patch of grassland and scrub conceals not only Slow Worms but Common Lizards too. |
Looking at the colour of their bellies is (in my opinion) the easiest way of separating the males from the females, but a little tip: when you pick them up do not lift them above your head. This is something I’ve made the mistake of doing and there’re a couple of reasons why you should just tip them on their side instead. One, when you hold it above your head you have to hold it at a bit of an awkward angle, so if the Slow Worm decides to wriggle around you won’t have a great grip to keep a hold of it. When this happened to me, I fell over backwards and probably could’ve dropped and crushed the little thing if I
By far the largest Slow Worm I've ever found. He was a good 35cm long, although they can grow longer than 40cm! |
The second reason is that when scared, one method Slow Worms use to try and shake off a predator is to excrete something called a musk. Basically, it’s a bit like on-demand explosive diarrhea. And by holding one up above your face you’re practically advertising it as a target.
With that out of the way, back to other signs to look out for. As I mentioned earlier, there are many different variants and mutations in the colour of Slow Worms, and one of these only occur in males. Normally the backs of the males will just be smooth, without any markings, but some you’ll find have conspicuous blue spots lining them. And from what I’ve read, these are exclusive to males, so it’s an immediate giveaway and is surprisingly common too.
Slow Worms are unlike many other species in that both genders grow to be the same size, and the only
real size difference is in their heads. In order to fight off predators and rival males, the heads of the males are visibly wider than the females. This is clearest when you look at where the jaw connects to the skull, and you’ll see defined bulges in some individuals (the males) but not others. Looking from above, this gives themales a distinct “neck”, where the body tapers inwards behind the head.
Characteristics of a female Slow Worm
Unlike the males, the females lack this "neck", having much slimmer heads, although it takes a bit of practice to get your eye in and be able to notice this.
The colour of the females clashes a bit with the males' though being anywhere from a warm gold to a dark copper on top, with the males also often being gold. Normally though the females will be a warmer tone, and the males won't shine as much. Regardless of what colour they are on top, their flanks will always be contrastingly darker, anywhere from a chestnut brown to black, compared to the males which
The black belly of a female-this one was sadly dead. Likely killed by a cat because it was in a very built-up area. |