Learn Spanish (Latin America): Su instinto es fuerte; capaz que sobreviven. - Her instinct is strong; they might survive.

While words expressing doubt (like quizás or tal vez) often trigger the subjunctive, the colloquial phrase capaz que can take either the indicative or the subjunctive. Using the indicative (sobreviven) generally shows a higher degree of certainty or a strong prediction—more like saying "I bet they survive." Here, the fact that the instinct is strong gives the speaker confidence, making the indicative a very natural choice.

I learned that capaz means "capable." How does it translate to "might" in this sentence?

You are right about the literal meaning of the word (for example, ella es capaz, meaning "she is capable"). However, in everyday conversational Latin American Spanish, capaz or capaz que has evolved into a widely used expression meaning "maybe," "perhaps," or "there's a chance that."

The translation says "Her instinct is strong; they might survive." Why does the subject change from singular to plural?

The grammar reflects a specific situational context. Her instinct (su instinto) is the driving force, but the survival applies to a whole group (perhaps a mother animal and her young, or a guide and her group). The plural verb sobreviven tells us the subject has shifted to "they," even though the pronoun ellos or ellas is dropped.

How do we know means "her instinct" and not "his" or "their" instinct?