To the Chinese people (whether in China, Taiwan, Singapore, HK, America, Malaysia etc) there is no other animal more useful than the pig.
Why do I say that?
Because every part of the pig is being used. And I mean EVERY part. Almost.
For consumption -
Pig meat, basically pork (pork chop, BBQ pork, roasted pork etc)
Pig skin (below, fried skin sold in China)
Pig brain (below tonic pig brain soup)
Pig intestines, stomach (with black sauce)
Pig liver (with soup or stir fried)
Whole pig (below, used in Chinese wedding dinners
and as an offering to Chinese gods and some places in Europe)
Pig bones (with soup)
Pig lard (for seasoning)
For other uses -
Pig skin - for sole of shoes, or even wallets
Whole pig - Below, In mythology and the Chinese religions, the pig is sometimes an icon
Pig head - And not forgetting, illegal loansharks in Singapore hang pig heads outside the homes of people who owe them money. (o_o'')
OWE MONEY, PAY MONEY.
I think only the eyes, nose, teeth and butt are not usable. But who knows, somewhere in this world, someone might be eating pig's eyes, nose, teeth and butt.
So I conclude, the PIG is the most useful animal on earth. Not the dog, not the cat, not the chimpanzees, not the horse or the cow.