The early Christian thinkers gave little attention to it, and that little was devoted to transforming it into something absolutely opposed to his whole spirit and method; in place of it they developed the Physiologus and the Bestiaries, mingling scriptural statements, legends of the saints, and fanciful inventions with pious intent and childlike simplicity.

In place of research came authority--the authority of the Scriptures as interpreted by the Physio Cogus and the Bestiaries--and these remained the principal source of thought on animated Nature for over a thousand years.
Occasionally, indeed, fear was shown among the rulers in the Church, even at such poor prying into the creation as this, and in the fifth century a synod under Pope Gelasius administered a rebuke to the Physiologus; but the interest in Nature was too strong: the great work on Creation by St.Basil had drawn from the Physiologus precious illustrations of Holy Writ, and the strongest of the early popes, Gregory the Great, virtually sanctioned it.
Thus was developed a sacred science of creation and of the divine purpose in Nature, which went on developing from the fourth century to the nineteenth--from St.Basil to St.Isidore of Seville, from Isidore to Vincent of Beauvais, and from Vincent to Archdeacon Paley and the Bridgewater Treatises.
Like all else in the Middle Ages, this sacred science was developed purely by theological methods.

Neglecting the wonders which the dissection of the commonest animals would have afforded them, these naturalists attempted to throw light into Nature by ingenious use of scriptural texts, by research among the lives of the saints, and by the plentiful application of metaphysics.

Hence even such strong men as St.Isidore of Seville treasured up accounts of the unicorn and dragons mentioned in the Scriptures and of the phoenix and basilisk in profane writings.

Hence such contributions to knowledge as that the basilisk kills serpents by his breath and men by his glance, that the lion when pursued effaces his tracks with the end of his tail, that the pelican nourishes her young with her own blood, that serpents lay aside their venom before drinking, that the salamander quenches fire, that the hyena can talk with shepherds, that certain birds are born of the fruit of a certain tree when it happens to fall into the water, with other masses of science equally valuable.
As to the method of bringing science to bear on Scripture, the Physiologus gives an example, illustrating the passage in the book of Job which speaks of the old lion perishing for lack of prey.