1. Give a new iguana a couple of weeks to settle in before starting the taming process. Establish a routine for feeding, cleaning, etc. - a predictable daily routine will provide a sense of security for the iguana.
2. Talk to the iguana as you do routine tasks, and keep the iguana in a place where it can observe the you going about your routine. This will help get him used to our presence.
3. Spend time just watching and talking to the iguana. Use his name as they do tend to recognize their names.
4. Place your hand in the cage and approach the iguana. Do this from the side rather than from above, which the iguana will likely percieve as a threat. If the iguana makes aggressive postures or scrambles around in a panic, back off a bit but keep trying, while speaking in a soft gentle voice. Make sure movements are slow and smooth. If you immediately stop trying, the iguana thinks he is training you! Repeat this step for a while until the iguana is more used to your hand.
5. Try to pet the iguana. The same tips apply as for the previous step.
6. Now try to pick up the iguana. If it is a smaller iguana, then scooping it up under the belly should be sufficient, but if he is larger, then supporting both under the belly and the pelvic (lower belly, upper tail) areas will be necessary. Before attempting this, make sure the room is iguana proof, with no means of escape (block of any space, however small, an iguana could squeeze through) and any breakables put away (remember iguanas are good climbers too). If the iguana gets away on you, this will help in the capture process.
7. Try not to put the iguana down until he is calm - that way it learns that being calm is what gets it put down rather than struggling. If the iguana gets away from you, don't panic and chase him - let him calm down, then approach slowly speaking quietly. You may end up having to chase the iguana of course, but this is best avoided if possible. Never grab for the tail - iguanas can drop their tails as a defense and you will be left holding a tail while the iguana is still on the loose!
8. As the iguana becomes more accepting of handling, you can be more responsive to his moods - if he is usually okay with handling but is tense or signaling with body language that he is not comfortable, then you can respect that.
The following are excellent in depth resources that will help with this process:
- Taming and Socialization - by Melissa Kaplan - Chapter 5 of this PDF document is actually a complex series of articles on behavior, socialization, and taming that every owner should read.
- Taming an Iguana (and Aggressiveness During Breeding Season) - by Tricia Power - excellent advice on taming as well as the body language of iguanas.