Seasonal changes in the thyroid gland of Indian spiny tailed, sand lizard, Uromastix hardwickii (Gray) male.

The thyroid gland of Indian spiny tailed, Sand lizard, Uromastix hardwickii is in the form of a ribbon like structure situated beneath and across the trachea. The histological appearance of the thyroid gland, follicular cell-height, nature of colloid and its relative weight studied over a year showed a seasonal variation and cyclic activity, which were found to be more in summer months than the winter and also correlated with the active and inactive phases of reproduction. In the month of May/June, when the environmental temperature was high the thyroid appeared to be most active, while in December/January, when the environmental temperature was low, the thyroid was almost inactive.