Write $\subseteq$ or $\nsubseteq$ in each blank so that the resulting statement is true.
$\{x \mid x$ is a bear $\}$ $\{x \mid x$ is a white bear $\}$

Step 1 ：The problem is asking to determine the correct subset symbol to use between two sets. The first set is the set of all bears and the second set is the set of all white bears.

Step 2 ：In set theory, a set A is a subset of a set B (denoted by A ⊆ B) if every element of A is also an element of B. On the other hand, if there exists at least one element in A that is not in B, then A is not a subset of B (denoted by A ⊈ B).

Step 3 ：In this case, every white bear is a bear, but not every bear is a white bear. Therefore, the set of all white bears is a subset of the set of all bears.

Step 4 ：Final Answer: \( \boxed{ \{x \mid x \text{ is a bear} \} \supseteq \{x \mid x \text{ is a white bear} \} }\)