Rashi, Targum Yonasan: They are cats.

Radak: It is a kind of Chayah found in the Midbar.

Malbim: They are a Chayah that comes from Iyei ha'Yam (islands).

Rashi #1: Cats will dwell b'Armenosav ¹ (in its castles). "V'Anah" is [dwelling,] like "v'Ansah Shamah" (Hoshe'a 2:17), "u'Me'onosav Terefah" (Nachum 2:13).

Rashi #2: "V'Anah" is an expression of answering aloud. Radak - this is like "Enu Lah" (Bamidbar 21:17), "va'Ta'an Lahem" (Shemos 15:21), v'Ansah Shamah" (Hoshe'a 2:17).

Malbim: In the officers' palaces, there is a big palace where all gather together for Simchah and songs. Almenosav are small rooms for a person to be alone. Iyim (from islands) cannot join with other Chayos, so they will scream in the small rooms; Tanim will scream in the big palace.

Metzudas Tziyon: They are a kind of snake.

Rashi: Snakes will dwell in their pleasure palaces.

Radak: The time of Bavel's destruction will come soon.

Malbim: There are two reasons why a kingship ceases. (a) It is a punishment when its measure of sin is completed - "v'Karov Lavo Itah." (b) Its time finished, and the time of another kingship came. A kingship cannot 'take' authority over a time designated for another kingship.

Rashi: Its good days will not last, for Yisrael were already promised "l'Fi Melos Bavel Shiv'im Shanah Efkod Eschem" (Yirmeyah 29:10). That Pekidah was via Koresh Melech Paras, who will take the kingship from Daryavesh ha'Midi; both Madai and Paras joined against Bavel, and stipulated - if the kings will be from us, the governors will be from you.

Radak: Its days of serenity will not last; they will be few.

Malbim: This is the second reason why a kingship ceases - its time finished, and the time of another kingship came. A kingship cannot 'take' authority over a time designated for another kingship. The years allotted to Bavel were 70; they finished, and the time came for Malchus Yisrael ¹ and rebuilding the Beis ha'Mikdash.