Worm by Name Worm by Nature

The face of a slow worm portrays that of a lizard rather than a snake, with a notable eyelid. 

Of all our reptiles slow worms must be the least seen, although I can find them relatively easily, I rarely come across them by chance, without looking. This is largely due to their secretive, subterranean existence and preference for not basking in the open (with occasional exceptions). Slow worms are lizards rather than snakes, as their eyelids show (a feature missing in snakes), a close look at the face also shows that of a lizard , the tongue flickers but is un-snake like despite being notched it lacks the deep fork we see in snakes, also the mouth lack a groove for the tongue to enter and exit. Slow worms also have very lizard like scales, and are shed piecemeal rather than in one piece, as we see in snakes.

Slow worms have wide tongues, with a grove in the end, unlike the forked tongue of a snake. Although if you get this close to one and you still don't know if its a snake or lizard, good luck :).  

Slow worms unlike snakes tend not to bask in the open but regularly bask within vegetation where light can penetrate through it. They thermoregulate by basking under refuge such as sheets of tin, sacking and natural mats of bracken, stones and logs where they can absorb warmth via body contact with the material in which they are hiding under. Slow worms are also regularly found in compost heaps as well as ant hills, and like their name suggests are very good at burrowing in loose soil and decaying vegetation. Slow worms spend a great deal of their time buried in loose soil or underground in cracks, crevices and rodent burrows. Hibernation occurs in similar places deep enough to avoid frost penetration. Slow worms tend to emerge from hibernation slightly later than adders and common lizards with which they share their habitats locally. Although the first individuals are found around March, numbers tend to peak around May/June.

Slow worms tend not to bask in the open, however individuals are occasionally found in the open, close to cover. 

Slow worms like adders are not a species adapted to overly warm conditions and summer periods of drought with high temperatures causes them to retreat deep underground. Handling slow worms is unadvisable like with other reptiles they are delicate creatures and can easily be damaged. The latin name Anguis fragilis literally means fragile snake, as the slow worm will readily shed its tail, which continues to thrash helping distract would be predators. Like in other lizards the tail never truly grows back, but grows into a blunt cap.

The photos show Male slow worms, females tend to show darker flanks and undersides and have a smaller thinner head. 

Slow worms can often be found after light rain or dew early in the morning or in the evening in the summer when the white netted slug (seen in an earlier post) is present. Small slugs are a key component of the diet as are other soft bodied invertebrates like worms, snails, spiders and insect larvae. Despite often associating with ants nests, ants are not considered to be a significant part of the diet. Prey is detected similarly to snakes with scent particles picked up on the flickering tongue, with prey movement triggering the strike.

Slow worms show a clear neck. 

Like the common lizard and adder, slow worms give birth to live young, mating occurs later than the other local reptiles, around June. Mating is quite aggressive with males biting the back of the females head and entwining himself around her, males will also occasionally fight with one another over a female. Copulation can take upto 10 hours and is rarely observed (like courtship) as it predominantly occurs in subterranean hideaways like much of this species life. Gravid females bask longer and spend more time in open sunlight, they also continue to feed during pregnancy unlike most of our other reptile species. Young are usually born between August and September.

Slow worms can be very long lived with the record being 54 years for a captive specimen in Denmark. 

Slow worms are a relatively long lived species, which lives longer than most other similar sized vertebrates with 10-15 years being quite normal. A record of 54 years in captivity shows the age the species can potentially achieve with few environmental pressures. Predators include crows, birds of prey, foxes, rats and hedgehogs. Occasionally adders and grass snakes will eat slow worms, but the impact of these two predators in negligible.   

In addition to slow worms, its hard not to find adders at the moment with numerous individuals out basking in the thin cloud today. 

Adders flatten their body to absorb as much heat from the sun as possible, especially on days like today which had thin cloud and no direct sunlight. 

I was so preoccupied with photographing slow worms I almost rolled onto this adder. He was very confiding and allowed some photos, although by this point it had clouded in. Perhaps the largest male I have found this year, a striking animal.  

You know its a good day when you have 3 species of reptiles at your feet and ospreys migrating north over your head.