from wikipedia on katakana:
Technical and scientific terms, such as the names of animal and plant species and minerals, are also commonly written in katakana.[5] Homo sapiens (ホモ・サピエンス Homo sapiensu?), as a species, is written ヒト (hito), rather than its kanji 人.
Katakana are also often, but not always, used for transcription of Japanese company names. For example, Suzuki is written スズキ, and Toyota is written トヨタ.