An equilibrium for competing sapient species

What scientifically, socially and logically plausible mechanisms allow two (or more) sapient land-based species (either closely placed on the phylogenetic tree, such as Homo sapiens and Homo neanderthalensis, or only distantly related) to develop and deploy tool-use on the same world in a similar evolutionary timeframe?

The situation needs to be such that one species' sapience and development of tool use does not eliminate the chances of the other to establish a similar base.

When I say land-based I mean that animals which are entirely aquatic and cannot exist on land at all are not allowed. Amphibian species which live in very wet environments and deploy tools in both aquatic and land-based environments are allowed.

Any symbiotic or altruistic approaches should have a suitable justification.

Edit to add: Simply having separate sapient species evolve on different continents and not in contact with one another is not valid since if that is the case I will have no story since at the stone age level of technology neither set of tool users are likely to be capable of crossing the sea that separates them. I want them to have a shared history.

posted over 8 years ago

rumguff‭

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