Friday, March 20, 2009

How to catch a lizard

Come on, admit it, it's a skill you've always wanted to learn. Bridget Murphy is a PhD student studying the reproductive physiology of Eastern water skinks. She first learnt to catch lizards in her backyard as a kid when her mum squirted them with the hose to slow them down! Here she shows us how it's done sans hoses.

Step 1: Decide what type of lizard you want to catch and figure out where to find them .

Lizards are all different shapes and sizes and live in a range of habitats. Many lizards bask during the day, so you are likely to find these lizards in the morning lying on surfaces that will warm up quickly. By the middle of the day in summer, these surfaces usually get too hot and lizards will find a cooler shelter to wait it out until the late afternoon.

Top: A rainbow skink (Lampropholis delicata).

Some lizards don’t bask and are fossorial. They normally live in the soil under rocks, logs and leaf litter and may only come out at night. Fossorial lizards have a specialised body shape that makes them suited to their life underground. They are long and streamlined and have reduced legs. Through evolution, some have completely lost their legs and these are usually called 'legless lizards'.

Burton’s legless lizard (Lialis burtonis).

Lizards that live in the desert are adapted to living in a hot, dry environment. Spines on the skin of the thorny devil, for example, are arranged in such a way to redirect rainwater that may collect on its back to its mouth. Pygmy blue tongues were thought to be extinct until one was found in the stomach of a road-killed brown snake about ten years ago. These lizards escape the heat in inland South Australia by living in holes created by spiders.

Thorny devil (Moloch horridus).

If you visit your local suburban creek, you are likely to find a range of lizards that make the creek bank their home. Water dragons can be locally common and like to bask on trees that overhang the water, leaping into the water and swimming to shelter if frightened. Similarly, water skinks like to bask on partially-submerged rocks to beat the heat in the middle of summer.

Eastern water dragon (Physignathus lesueurii)

Step 2: Figure out how to catch them

Generally, unless the lizard is in your backyard and/or is injured and needs treatment, you cannot capture lizards unless you have a valid reason. National parks and local councils have big problems with people catching lizards to illegally breed and sell for the pet trade. Scientists need ethics approval and a license from National Parks and Wildlife Services to work with or capture lizards.

So if you have the right licence, or if you find a lizard in your backyard and want to take a closer look, you need to first decide on a method to catch the lizard. This depends on the type and size of the lizard. Fossorial lizards can be caught by hand by looking under rocks and logs. Any rocks or logs that are moved should be replaced in the exact way they were found, since reptiles and other animals that live under these rocks will be disturbed. Basking lizards become very fast and sometimes impossible to catch after they have warmed up in the sun. Therefore, it is best to attempt to catch these types of lizards in the early morning or late afternoon. Small lizards can be caught by hand, or lured into your hand using an insect on a string tied to a long stick. Larger lizards can be noosed using silk string and a slip knot on a strong stick or fishing rod. Pitfall traps can be used for cryptic lizards or to measure the density of lizards in an area.

Step 3: Keeping your lizard healthy until release

If possible, lizards should be put in a dark cool place after capture. This minimises stress and prevents dehydration and overheating. Lizards should be kept in captivity for as short a time as possible. In captivity, lizards should be kept in aquaria with a source of food (usually insects and other invertebrates) and clean water in an accessible dish. Lizards are ectotherms and cannot generate their own body heat. Therefore, lizards in captivity will need a source of heat, such as a heat lamp, at one end of the aquarium to create a thermal gradient along which they can thermoregulate during the day. Lizards kept in captivity for long periods of time require a UV light or need to be taken out regularly into natural sunlight.

1 comment:

  1. Awesome article, thanks. One of my goals I have is to catch a wild bearded dragon. Wish me luck!