When photographing animals that are close to the ground, like this common iguana in Costa Rica, it is very tempting to stand at a comfortable adult height and shoot downward. That's a mistake. Getting low gives the subject greater stature, it makes the image more impressive, and the photograph seems more intimiate -- as if you are part of the animal's world.
Kneeling is better than standing, but even this isn't ideal. Shooting from eye-level is much better. Better still is if you can shoot from below eye level. To do this, you usually have to lie on the ground. In this picture of the iguana, the camera was below eye level, and that's why this photo seems so dramatic. As one gets older, it's harder and harder to do this -- and then to get up again -- but if you can manage it, the results are worth the effort.