A runaway southern tamandua was found unharmed in a penguin enclosure at a Tokyo aquarium Thursday, some 20 hours after it had vanished, aquarium officials said.

Staff at the Sunshine International Aquarium in Tokyo's Ikebukuro district said the southern tamandua disappeared from Zoo Zoo House — a cabin in which small animals are allowed to run freely — around noon Wednesday.

But the animal was spotted around 8:30 a.m. Thursday among some 60 penguins that were atop an artificial rock in a facility called Penguin Beach, located just 2 meters away from the cabin, according to aquarium officials.

The creature in question is Tae, a 2-year-old female that arrived at the aquarium from Paraguay when she was about 5 months old, the officials said.

Officials said the animal apparently escaped after it found the door to the cabin open. An employee who had cleaned the facility had inadvertently left it unlocked, according to the aquarium.

Some 70 employees were enlisted in the search for the animal, one of four kept at the aquarium. There are only nine southern tamanduas in Japan.

The aquarium did not close after the animal disappeared because it is tame and was not expected to harm humans, officials said.

"Southern tamanduas have a tendency to crawl into small spaces, and that's why we had difficulty finding it," one employee said.