Symbolism of tortoise at temples

Many a Hindu temple has an etched or stone-made tortoise on the doorstep of the entrance. It always faces the sanctum sanctorum. This amphibian creature has four limbs, a tail and a head. At the slightest suggestion of a threat to itself, it is quick enough to withdraw its limbs and head under the safe protection of the hard shell on its back. The Bhagavad Gita describing a man of wisdom and perfection states in chapter 2 verse 58: “When like the tortoise which withdraws on all sides its limbs, a man of perfection withdraws his senses at will, from sense objects, then his wisdom becomes steady.”
Using this symbolism the Gita aptly conveys the art of mental self control. Thus the five senses of knowledge are eyes, ears, nose, tongue and touch. These five senses along with mental perceptions are capable of bringing to our bosoms all the disturbances that can agitate our mind. The ability to mentally withdraw at will any of their senses from their fields of objects is known in Yoga Shastra as Pratyahara, controlling the breath as Pranayama and withdrawal from mental wanderings as Uparati. When a man of wisdom understands the futility of searching for the crumbs of happiness in the wayside gutters of sensuousness he withdraws mentally and attaches his mind to the source of all bliss, the pure consciousness, the Atmasukh. Thus, as one enters a place of worship the tortoise at the entrance indicates that as he withdraws his five limbs and one head to save himself from harm, so also a person should withdraw his five senses and the mind from worldly preoccupations, and then with an agitation free pure mind appear before the Lord in total inner purity. Only then is man capable of focusing on the Divine. Just as the tortoise that glides effortlessly from land into the quiet depths of deep waters, so should man glide easily from the agitations of the outer world to the inner depths of beatitude and peace.