。
Apes are highly intelligent.
Literal
Apes [topic-は] intelligence [subject-が] high.
類人猿 ('ape, anthropoid') is 類人 ('man-like') + 猿 ('monkey') — 'man-resembling monkey.' Note how the sentence uses the double-subject pattern: 類人猿 topicalized with は, then 知能 ('intelligence') as the inner subject with が. Standard for 'X has characteristic Y' descriptions.