What did the two carabao statues stand for or commemorate?

Although no law decrees the carabao to be a national symbol, most Filipinos consider it to be the national animal. The carabao is one of the most important animals in the country, especially in agriculture. Carabao skin was once used extensively in the Philippines to create a variety of products ,including the armor of pre-colonial Filipino warriors. I can't find anywhere that it says why they were bult, but I am uming reason above is why.