I doubt gambling is in nature. Investments based on reason pay off. Evolution shapes for sensical moves.

Humans invented gambling as a rigged game that mimics what's in nature, perversed for profit.

The "natural" form of gambling is this.

You need to collect food, do you go to where you know there are berries (low value but high likelihood of finding), or scout off to find a herd of deer? (High value but low likelihood of finding).

Looking for deer wouldnt be walking off in a random direction. You check water holes, known clearings, known fields.

Each of these is an operation (walk to X and look), each has a low probability of meeting a deer.

This is a variable reward scheme.

The result is optmize foraging practices - you mostly hunt for deer then fall back to berries. In larger groups some will gather berries some will hunt.

Contrary to popular thought hunter and gatherer were not separate occupations.

But we don't say a hunter is out gambling. We say out hunting. That there is investment, uncertainty, risks, and invariably some randomness in the returns, it's certainly not random. Gambling for the the most if not the whole part is random.

Broadly speaking, gambling is just making decisions without knowing the future. It's everywhere.

Gambling is taking a bet without any clue about the future.

Nothing is done with certainty what the future will be. Yet we don't say we are constantly gambling, without some people do.