The nymphs that lived in Illyria were the planet’s closest species to a human. They were not, however, adapted to caring for cows and bulls. As such, the bull and cows did not seem to stand much chance in their new environment. The bull calf, however, saved at least two of the cows. As the young bull was growing, he fed on the milk of the older cows, thus serving to alleviate the pressure to some degree. as He did not, however, save all of them. Three died of udder explosion.
The nymphs, watchful as the were, noticed the young bull’s behavior, and, curious as they were, attempted the same. The cows, then, simply assumed that it was either the young bull or some very small farmhand doing whatever it was they always did. This also helped prevent udder explosion. The nymphs discovered an easy way to feed their young; the nymphs, therefore, initiated a symbiotic relationship with the cows.
Another problem for the heavy animals was food. On Earth, cows had a steady diet of hay, corn silage, and grain. The cows ate two kinds of hay, first cutting and second cutting; the first cutting hay grows in May and June, and second cutting hay comes from alfalfa that grows after a grass cutting. The corn for the corn silage is grown, the entire plant cut down, and the crop put into a silo until it heats and ferments. This provides a year-long food item for cows and heifers. For the grain, a farmer mixes dry corn, oats, and soy; occasionally, the farmer would also add vitamins. The mix is ground up together and stored for the cows.
For as long as they could, the bulls and cows survived on chest-high leaves from shorter trees and shrubs on the ground. The birds and monkeys that normally ate these shrubs, then, adapted to eating leaves higher on trees. This temporarily solved the problem of food. But only temporarily.
Another immediate problem was reproduction. On Earth, bulls and cows had people to help with the process; but people had since abandoned the bulls and cows, so they were left to their own devices. After breaking one cow’s back (who, sadly, did not live long thereafter), the adult bull discovered that it was best to copulate with a cow when she was lying down. Unfortunately, this only succeeded once. Again, this solution was only temporary, but at least the adult bull begot a cow. This time, the adult cow calved a cow and not a bull.*
As the young bull and the young cow grew, they shared their milk with an entire population of tree nymphs. Nor did the adults produce as much milk, as they were not eating as much as they had been fed on Earth. Therefore, the calves did not grow as large as they might have with a fuller supply of milk. Also, the larger cows frequently stepped on small forest dwelling rodents, usually killing them instantly. The young calves discovered that they could get the same satisfaction, if not more, from eating a rodent than from eating quite a few leaves. Thus was the beginning of a carnivorous cow/bull.
With their carnivorous tendencies came a need for more meat substances. In following the adults through grazing pastures, the calves, now older, discovered the pond. At the shore of the pond, the calves managed to catch slower, dumber amphibians, and discovered that they provided similar satisfaction as the rodents.
When they reached the reproductive age, the younger cow and bull found the process much easier than their parents had, as they had developed a bit smaller, since they had not recieved as much milk at a young age and they were not fed as frequently as their parents had been on Earth. Therefore the pair managed to help seed more generations of smaller cows. As the generations got smaller, they also got faster to a certain extent, so they could catch their own food. As the cows and bulls adapted, so did the smaller animals – natural selection played its part in making some amphibians and rodents even faster while keeping some slower for the cows and bulls.
Although the female cows also grew
smaller, they still produced plentiful milk for their own offspring and
for the nymphs. The nymphs, though, had to resort to acquiring the
milk when the cows were eating leaves (standing still) instead of chasing
food, or when the cows were sleeping. Thus, the cows and nymphs still
had a symbiotic relationship.
*(It is possible, however, for a cow and a bull to physically
copulate. This is just for the sake of the story.)