Can a Smart Contract Itself Act as an Oracle?

A smart contract can technically act as a limited, on-chain oracle by reading data from another contract or recording internal blockchain data, but it cannot independently fetch external, off-chain data. For instance, it can read the balance of a token or the result of a prior on-chain vote.

However, for real-world information like the USD price of Bitcoin, a dedicated external oracle service is required to bridge the data gap.