Evolution of a Lizard Room, Part VII: Egg Laying

A highly technologically advanced egg-laying location: a used bulk-size yogurt container (generously donated by various staff in the department) filled with moist vermiculite. In this case the lid is removed so that you can see the vermiculite inside.

While Anolis distichus may have plenty of options for where to lay eggs in the field, we needed to do a bit of experimentation before landing on a good place for them to lay their eggs in the laboratory environment.  Other anole facilities tend to allow their lizards to lay eggs in the soil of potted plants, and we originally had our lizards laying in the soil substrate of their cages.  However, eggs that spend time in soil tend to desiccate quickly, sometimes even before they’re discovered.  Given that we knew our production would be limited, we wanted to avoid this risk during our breeding experiments.  We arrived at a solution that is a combination of breakfast and gardening: yogurt cups filled with moist vermiculite.

Very few steps are necessary to make such a wonderful egg laying vessel.  First, we made two anole-size holes in the yogurt cup: one hole on the side a little above half-way up the body of the container and a second in the lid.  We generally made these holes using a soldering gun to melt the plastic.  The two holes allow the lizards easy access to the inside of the container to lay their eggs.

Inside the yogurt cup, we provide a few hefty handfuls of damp vermiculite.  This substance is often used by gardeners to increase the moisture content of their soil.  A five cubic-foot bag of vermiculite is shockingly lightweight, but don’t be fooled–a handful of vermiculite can hold a remarkable amount of water.  Vermiculite also retains that water for a long time, meaning that eggs laid in it have a relatively stable, humid environment.

Since adopting the yogurt cup and vermiculite method, we have seen a dramatic decrease in egg desiccation.  We still occasionally find an egg laid in the soil, but the lizards overwhelmingly prefer to use the yogurt cup environment for laying their eggs (and as a cozy hide-out).  In addition the implementation of the cups themselves, we also have a policy of weekly yogurt cup egg-checks, where eggs are removed for incubation (see Evolution of a Lizard Room Part VIII: Egg Incubation).

A breeding group cage containing a yogurt cup for egg laying--note the hole in the lid and the hole on the right side of the container for access to the vermiculite.

4 thoughts on “Evolution of a Lizard Room, Part VII: Egg Laying

  1. I’ll point out that we use a very thin layer of autoclaved potting soil as the substrate in the cage (I prefer this to synthetic substrates like turf for a variety of reasons, perhaps best outlined in a separate post). The layer of soil is too thin for females to nest in, so they are essentially forced into the yogurt containers.

  2. I still like the potted plants. I have absolutely no data on this, but it my gut feeling that the plants promote egg laying. I regularly see the females hanging out in the potted plants as if hiding from the other lizards or mentally preparing themselves for the egg laying process. In addition, the plant helps maintain slightly higher humidity in the cages (this we have measured) and I think helps keep the soil moist for about a week without additional watering.

  3. I agree about the potted plants, though we recently started using plant pots with fake leaves around them. This way, we can easily lift the “leaves” without frequently uprooting a plant in order to do egg checks. The females often hide in between and under the leaves. Before we switched to the fake leaves, we found most of their eggs close to the roots of the plants.

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