How do animals fancy each other Page 2 of 4

Evolution theory says that natural selection is animals best suited to environment and go on to have more babies. Just sticking with the fancying for now , but there will be a million other differences of course in any species and type.
So 8 million animal species exist today on our planet. So 8 million different attractions desires feelings and thoughts to same species. Then there are types within the species. So with fish there are 30 thousand types all looking for own type. So salmon and pike and carp etc look for each other. That’s a lot of different desires and thoughts and thinking to find a partner.
Could brains do that. Of course since there are that many species with that many brain setups and if the brain is involved in the animals body structure maybe it is involved in the fancying. But we have to bare in mind that we don’t know much about the brain so we are left with conjecturing. And saying that they are wired differently is only a comfort to thoughts that we might have to explain anything like fancying.
Thinking in the evolutionary way it would mean that the brain neurons in every animal would be left to natural selection. All brains are made of the same stuff but the shear number of brain plans necessary to get all that fancying doesn’t seem possible using our random mutations and natural selection ideas. It would go wrong too many times if was left to our evolving idea. And if it went wrong just once , there would be chaos on a monumental scale , leaving animals fancying other species. But it doesn’t go wrong.
In fact , nothing goes wrong. There are of course illnesses and deformities , but in general , arms and legs and eyes and ears and hearts , form in the body in the place that they should do. And that goes for fancying. And all of them , including thought and movement , have to exist at the same time.
But back to fancying. There are 8 million species of animals today. There are then types and breeds and then there would have been all those that are now extinct.
And that is just on this planet.
If the nearest other planets to ours are shown one day to have life then we are going to take a leap and say that all planets with suitable environments to support life have life and plants. That’s billions of planets in our galaxy alone. If they all had say 8 million species then that number become so much bigger. So much so that imagining the brains being involved in the fancying to be questionable especially if they have similar animals as here. Then add in all the galaxies in the universe that we can see with our telescopes that might have that fancying and it would be in numbers that we can’t imagine of animals fancying their own species.