Not big? Fairy Tale

Once, a poor man had three sons and only one ox, which was exceptionally large. To graze the ox, the eldest would ride on its head, the middle son on its back, and the youngest on its tail. One day, while they were grazing, the ox stopped grazing. The youngest, sitting on its tail, said:

– It has been ten days since the ox has grazed, please tell the middle brother, who sits on its back, about this, – and entrusted a passing traveler with the message. The traveler journeyed long and, in the evening, reached the middle brother sitting on the ox's back. When the traveler conveyed the youngest's message, the middle brother replied:

 – I was also starting to suspect that the ox's sides were swelling and its belly was tightening. If you happen to see our elder brother on the ox's head, please let him know about this, – he said. The traveler continued his journey throughout the night and reached the ox's head at dawn. He told the boy sitting on the ox's head:

– I have been walking for a day and a night without stopping. The youngest on the tail says it has been ten days since the ox has grazed, and your middle brother is concerned that the ox's sides are swelling and its belly is tightening, – he said. The boy at the head of the ox responded:

– Ah, it seems the ox is thirsty and is looking for water. The ox has not found enough water from the usual places. Now, he entrusted a traveler passing by to pass a message to the middle brother:

 – I am going to look for a lake to water the ox; please meet the middle brother and tell him to hurry and make the ox graze, – he said. The traveler walked on and, in the scorching heat, reached the middle brother sitting on the ox's back, relaying the elder brother's message. The middle brother replied:

– If you get there early, please tell our youngest on the tail to urge the ox to graze more, – he said. The traveler reached the youngest on the tail as the sun was setting and conveyed the middle brother's message. Then the boy sitting at the head of the ox took the ox to a vast lake to water it. The ox took only three gulps of water and still seemed thirsty. While the three of them were dismounted, a white-tailed eagle swooped down from the sky and carried the ox away. The eagle, flying around with the ox, landed on a tree that was actually a ram's horn. As the ram shook its horns, the ox caught the eye of an old man who was casting a shadow on the ram's beard. The old man rubbed his eyes and said to his wife:

– Something has gotten into my eye; please help me clear it out, – but as his wife searched and could not find anything, she put him on a yellow horse, gave him a stick, and sent a mounted man to help. This man searched for three days to find the ox, and finally, he discovered it by the river, dead from a painful death, and dragged it away. Two or three years later, grass grew over the ox's carcass, and its bones became part of the landscape. A village settled on the plain of the shoulder bones, and it became a grazing ground for livestock. One day, a fox dragged a shoulder bone away from the village with its grazing livestock. The villagers chased the fox with racehorses, hawks, and hounds, catching it in the end. They tanned the fox's skin, and the mistress gave it as a cap to her son, but it was not quite enough to cover one ear.

– Tell me, children, who is bigger?