Tangentially,
subalpine is an elevation zone ecosystem directly below the treeline (~10k feet above sea level).
When Natsumi is calling Yura "
savage," there's an inherent pun as Yura mentions "subalpine," since "sava" and "suba" basically sound the same in Japanese.
Plus, "
Subaru" as a Japanese name is referencing a star cluster/constellation (hence
that automobile brand's logo), but it is ALSO a pun since "
subaru" is the very same "
sub-al(pine)" word the Japanese use for that elevation zone and the fact that brand is big on marketing its compatibility for outdoor camping and mountaineering!