Waco (FOX 44/KWKT) — The Cameron Park Zoo released the results Thursday of the investigation into the deaths of mother and daughter giraffes, Penelope and Zuri.

Penelope died Wednesday, July 19th. The zoo says reports from outside laboratories and specialists show the primary issue was muscle trauma in the form of extertional rhabdomyolsis.

The more common term for that is capture myopathy, which is characterized by a breakdown of muscle tissue. It most commonly occurs when animals overexert themselves, but Cameron Park Zoo says animal care staff did not see any activity fitting that description.

The zoo says Penelope’s condition rapidly led to difficulty transitioning from lying down to standing up. That can cause several issues, including muscle damage, aspiration of stomach contents and gastrointestinal disease.

Zuri died a few days after her mother, on July 22nd. Cameron Park Zoo says experts found that she had an infection of the gastrointestinal tract which spread to her bloodstream. That caused sepsis and made it into her lungs.

Zoo officials say the stress of losing her mother and transitioning to being bottle-fed may have also contributed.

The staff veterinarian for the Cameron Park Zoo released this statement:

The Cameron Park Zoo is still mourning the loss of Penelope and Zuri, but this information helps us understand what we were dealing with. It gives me comfort knowing that we provided the best medical care we could under the circumstances. Giraffes are always challenging to treat due to their size and unique physiology. I hope that this information may contribute to the growing body of knowledge about their care.”

Dr. James Kusmierczyk/Cameron Park Zoo

Both Penelope and Zuri were Masai giraffes, which is the largest species of giraffe. They can be found in Central and Southern Kenya, as well as in Tanzania. They are known for their distinct and irregular star-like blotches that extend to their hooves.