Photo via Smithsonian’s National Zoo.

A Grevy’s zebra that bit a keeper at the National Zoo last month—spooking a gazelle and causing it to run into a wall and die—was caused by human error, a Smithsonian safety inspector concluded.

According to a release, a thorough investigation of the incident—wherein a male zebra named Gumu bit and seriously injured a zoo keeper in the early morning of November 18—found that the “gates and doors from the Grevy’s zebra stall to the adjoining yard where the keeper was working were not secured,” which is a breach of protocol. The investigation concluded that there were no engineering or mechanical failures in the zebra house.

The Zoo also acknowledge that Grevy’s zebras are, in fact, considered dangerous animals, and that the protocol isn’t for humans and the zebras to ever be in the same space together. Unfortunately, there were no other witnesses to describe how the zebra and zoo keeper ended up in the same space.

It is the Zoo’s standard practice to evaluate and respond to all internal or external evaluations of animal care and safety reports. All of the recommendations in this safety report are under review, and the Zoo is now conducting its own internal audit of management protocols. The Zoo did, however, recognize that the “injured keeper acted with clarity during the incident, which likely prevented him from receiving further injuries.”

That’s good!

The zebra reportedly has not exhibited any odd behavior since the attack.