Translation

hamusutā means "Hamster" in English.
It's a katakanization, a loan-word.

hamusutā is normally written with katakana, as ハムスター.
hamusutā written with hiragana is はむすたー.
hamusutā does not have kanji.
Romaji ha mu su taa
Katakanaハムスター
Hiraganaはむすたー

Orthography Notes

Further Reading

Wikipedia: ハムスター (Hamster)