Added 6 November 2000



In a world where lots of creatures that are not worms are called worms, earthworms truly are worms. To give them the correct description, they are annelid worms, as opposed to the parasitic worms that live inside a host. Annelid worms normally live outside of other creatures and are commonly found in the soil or on the seabed.

The annelid worms most commonly fed to herptiles are the earthworm variety, but some caution is called for here. Firstly, not all annelid worms are suitable as food, and some (such as the worms that live in compost heaps) may actually be poisonous. The other danger is that even the otherwise harmless earthworm in your flowerbed may be carrying chemicals from fertilisers or insecticides, either of which can affect the health of your pets. I therefore strongly urge anyone who wishes to obtain earthworms to buy them from a recognised source. They can be obtained from the better pet shops or often from fishing shops, where they are sold as bait. My preferred source is online suppliers of live food for reptiles.

Nutritional Value

I am not sure whether it is possible to gut load earthworms in the same way as crickets and mealworms. Earthworms, if I understand correctly, live on food (microorganisms or humus) found in the soil. For this reason, I do not think that earthworms should constitute the sole diet of any herp unless it can be shown that this is in fact the exclusive diet of the species in the wild. However, as part of a balanced diet they are very useful as they provide a change to the usual fare (let's face it) of crickets or pinks, and some herps do show a genuine taste for them.

Keeping your earthworms

Earthworms sold commercially, at least for reptiles and amphibians, usually come in a pot full of earth (which may be sterilised, I am not sure). They can live in this dampish soil for a few days, but really they should be offered as soon as possible. There is no advantage in keeping them for a long time and some do inevitably die if kept longer than a few days. As they are more expensive, item for item, than crickets or mealworms these losses are costly. If you must defer offering them for a day or two, keep the tub in a cool place, such as a cardboard box in a dark part of the pantry.

Who can benefit from earthworms?

Not all reptiles or amphibians will take earthworms, and even within a species the taste for annelids seems to vary from individual to individual. For example, of my two plated lizards (Gerrhosaurus major), Uther the male tends to shun them, whereas Ygrane the female avidly devours them. Similarly, my Cunningham's Skinks (Egernia cunninghami) may or may not take them depending on what fancy is taking them. Digit, our Savannah Monitor lizard, absolutely relishes them, which is somewhat curious as I do not know how common they would be in a wild monitor's diet. However, as a rule some families or genera are more prone to take them than others. I am not so well versed in amphibian diets, but it seems that in general frogs, salamanders and caecilians are quite likely to take earthworms if they are the right size (ie not too large). Of the lizards, geckos will probably shun them, as may most other species that are primarily insectivorous. However, you should get good results if offering them to medium-sized lizards such as plated lizards. Zoffer (Feeding Insect-Eating Lizards, TFH) reckons that of the agamid lizards, Mountain Dragons (Acanthosaurus spp.) and Tree Dragons (Gonocephalus spp.) will take earthworms, as will the European anguid Scheltopusik (Ophiosaurus apodus). Some chelonians that are known to be mildly omnivorous, such as the hingeback tortoises (Kinixys spp.) may also be tempted, but don't overdo it.

Perhaps the safest way is to ascertain from literature whether or not your species does or can eat earthworms, either in the wild or in captivity, and then try offering a couple if so.

Offering your earthworms

I find that there are two ways of offering earthworms, dependent upon the temperament of the recipient. For shy or wary herptiles such as my adult Cunningham's Skinks, I find a shallow lid or bowl and place a quantity in there. Some may manage to wriggle their way out and into the substrate before discovery, but usually the predators manage to find the prey first (don't forget, most captives also use their Jacobson's organ to smell something long before they see it). For those animals that need individual feeding or that relish the annelids, I often offer them one at a time, preferably with forceps since you are less likely to get your fingers nipped should the recipient be very eager to grab the prey.

Whichever way you use, it is a good idea to knock as much of the earth off the worm as possible when you fish it out of the tub. In the wild it is doubtful whether herps ever eat clean, shiny dirt-free worms, but they probably don't relish a lot of dirt with their prey either.

A Note on Sizes

Tubs of earthworms seem to contain earthworms of often vastly different sizes, from the large fat ones to the very thin small ones. Use your judgement when offering earthworms, particularly to smaller herps. While the danger from consuming an earthworm without properly digesting it is not the same as with a mealworm, any prey taken, if too large, can be hazardous to health, particularly with regard to choking. Also don't forget that most herps do not chew their prey: amphibians especially seem to swallow it whole.

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