Zoo officials in Sydney have promised a sweeping investigation after five lions were able to briefly escape their enclosure on Wednesday morning. The animals—one adult and four cubs—were spotted roaming beyond their main compound at Taronga Zoo before 7 a.m., prompting an emergency lockdown. New South Wales police were summoned on a precautionary basis, but four of the lions were ushered back into their exhibit without issue. The fifth was returned after being safely tranquilized, according to 9News. No injuries to guests or staff were reported, officials said. In subsequent statements, the zoo hastened to clarify that although the five animals had exited their enclosure, they were still separated from the rest of the zoo by a six-foot fence. (A jumping adult lion can reach a vertical height of 12 feet.) Around mid-morning on Wednesday in Sydney, a Taronga spokesperson said that officials were still in the dark as to how the lions had breached their containment fence. The Taronga Zoo’s pride consists of two adult lions, named Maya and Ato, and their five cubs. The cubs—Khari, Luzuko, Malika, Zuri and Ayanna—were all born in Augus‌t.