The Torah begins with the account of the six days of creation. On the fifth day Hashem created the animals: "Hashem made the beast of the earth according to its kind, and the animal according to its kind and every creeping being of the ground according to its kind" (Bereishis 1:25). If one would take a cat, raise it in solitary confinement and then set it free, it would establish companionship only with other cats. Did the cat ever see itself in the mirror? How does it know where to find a home? The cat has what we call instinct, but who put the instinct into the cat? Rav Wolbe (Shiurei Chumash) explains that when Hashem made all the animals "according to their kind," He gave each animal a spiritual intuition to enable it to determine its own species.
There is no way to deny that the instincts possessed by animals clearly point to the hand of a Creator. A fly lays its eggs in a soft pod and then it bores a hole in the pod, because if it doesn't, the pod will harden and the offspring will not be able to exit their cocoon. There is a type of wasp which lays eggs and covers them with a thin layer of sand to protect them from other creatures. To ensure food for its offspring it catches flies, paralyzes them and leaves them in the nest together with the eggs. It does not kill the flies since they would spoil by the time the eggs hatch! Additionally, pigeons have an extraordinary sense of direction which guides them to their nests. A study was done in Germany where they flew pigeons to Brazil in an airplane and the birds made their way back to Berlin on their own. Then they flew them to London and the story repeated itself! The rooster, armed with an uncanny sense of when dawn is about to break, has acted as an alarm clock for innumerable generations. Who gave these creatures all this knowledge?
In a similar vein, Chazal assert that had the Torah not been given, we would have been able to learn modesty from a cat, and from an ant we would learn not to steal (Eiruvin 100b). The Torah delineates the proper procedure for one who must relieve himself: "You shall have a shovel with your tools, and it will be that when you sit outside, you shall dig with it; you shall go back and cover your excrement" (Devarim 23:14). The cat instinctively does what the Torah instructs us to do. Furthermore, people understand that it is incumbent upon them to refrain from stealing because the Torah restricts it and their intellect understands that it is wrong. Yet, Chazal inform us that most people violate this prohibition in one way or another. In contrast, the ant is instinctively meticulous not to take what does not belong to it! From where do these animals derive these amazing intuitive tendencies?
Instincts in reality are nothing less than clear revelations of Hashem in our world. There is no other explanation for an instinct other than a spiritual asset implanted in them by their Creator. Avraham Avinu discovered the Creator through contemplation of our awesome world, and the Rambam writes that every person could use the world as means of connecting to Hashem. All of creation screams emunah, so long as we do not close our ears to their cry!