Another animal has died at the Dallas Zoo, this time a female zebra named Keeya.

Keeya was a Hartmann's mountain zebra, and only 6 years old; the typical lifespan of a mountain zebra is 20 years in the wild, and 30 years in captivity.

The zoo shared her death on Facebook, which they said was due to a head injury but with no explanation for how it happened.

"Yesterday, March 22, Keeya was found unresponsive in the Giants of the Savanna habitat with a head injury," the post said. "Although none of our staff members witnessed the event that led to this injury, it is very likely that she was injured by another animal in the Savanna habitat."

Zoo veterinarians determined her injuries were too severe and she was euthanized. It was only then that they discovered she had a fractured spine, which they said caused paralysis in her lower limbs "from which it would be impossible for her to recover."

In the wild, mountain zebra form small herds which remain stable over many years. Mares usually remain in a herd for life.

Not the case for Keeya, who was acquired in 2017 from Austin breeder Bruce Fairchild, a former auditor for Sears Roebuck who began breeding mountain zebras in 2008.

Keeya was mated with Saba to produce an offspring, because baby animals are the moneymakers at zoos. She gave birth to Malawa, a male, in January 2020.

Mountain zebra herds generally have one adult male; otherwise they fight. With Saba and Malawa, the Dallas Zoo had two males.

Another female at the zoo named Wanda gave birth to a female, Sukari, in July 2020.

Keeya is the latest in a series of animal deaths at the Dallas Zoo:

• Subira, a 24-year-old silverback gorilla, died suddenly in March 2020, due to a cough, or maybe cardiovascular disease.
• Hope, a a 23-year-old Western lowland gorilla, died suddenly in November 2019 after being at the zoo for only two years.
• Ola, an 8-year-old female African painted dog, was killed in July 2019 by two other painted dogs, less than a month after she was transferred to the zoo.
• Witten, a 1-year-old giraffe, died in June 2019 during a physical exam under anesthesia when he suddenly stopped breathing.
• Adhama, a baby hippopotamus, mysteriously died in 2018.
• Kipenzi, a baby giraffe, died in 2015 after running in her enclosure.
• Kamau, a young cheetah, died of pneumonia in 2014.
• Johari, a female lion, was killed in front of zoo spectators in 2013 by male lions with whom she shared an enclosure.