The Toledo Zoo is formulating plans to change its giraffe herd after a series of unfortunate deaths over the last few years.
Four of the zoo’s Masai giraffes have died for varying reasons since 2016 — two of them in just the last two months.
“We had already started talking about moving from the Masai subspecies to the reticulated subspecies,” said Michael Frushour, the zoo’s curator of mammals. “We felt like they weren’t as prone to some of these issues.”
He explained that the population of Masai giraffes among facilities accredited by the Association of Zoos and Aquariums is much smaller than for the reticulated variety. A smaller population also means a smaller genetic pool and an increased likelihood of health issues.
“All four animals that have produced offspring here come from a shared maternal line,” said Kent Bekker, chief missions officer.
The zoo’s 8-year-old male, Trevor, suddenly collapsed Aug. 24 while on exhibit and died within minutes. The zoo received the results of a necropsy Friday that showed a condition called peracute giraffe mortality syndrome.
“The peracute giraffe mortality syndrome is a poorly understood metabolic issue that arises from a stressor which causes the animal to need more energy than it can consume, leading to death,” the zoo said in a statement to The Blade. “In this case, the stressor would appear to be severe anemia. The lab results found that Trevor’s bone marrow was not responding appropriately to make new red blood cells.”
The zoo said while Trevor died from the syndrome, the anemia would also have killed him.
“The lack of response by the bone marrow could have been genetic or infectious in origin, but no infectious agent has been identified based on lab results,” the zoo said.
In June, a 1½-year-old named Binti — Trevor’s daughter — was found down and had to be euthanized. Test results were ultimately inconclusive and the cause of her death remains unknown, but her lab results shared one similarity with her father’s: severe anemia.
“Binti being Trevor’s daughter lends credibility to the theory of a genetic origin,” the zoo said. “We have been monitoring Binti’s mother’s blood for signs of anemia or infection and none have [been] found.”
While Binti showed no symptoms or abnormal behavior before she was found down, staff were monitoring Trevor after noticing the day before that he was uninterested in being at the zoo’s giraffe feed deck and spent a lot of time staring off into the distance. Veterinary staff were notified and prescribed an antibiotic as a precaution while making plans for an examination.
On the morning of Aug. 24, staff noted Trevor had not eaten much and left behind what is usually his favorite part of his diet, Mr. Frushour said. Staff began planning to bring Trevor off exhibit, give additional medications, and place him in holding with video monitoring pending the exam, but he died before that could happen.
Mr. Frushour said Trevor’s symptoms were concerning, but not anything that would have indicated a critical emergency was imminent.
“We had no reason to believe the way it turned out would be the way it turned out,” he said. “It was quite a shock.”
Dr. Dennis Michels, the zoo’s veterinarian, said Trevor was already dead when staff got to him just a few minutes after he collapsed. The giraffe was not breathing and had no heartbeat, he said.
Other recent deaths include a 4-year-old female, Bahati, who was found down in 2018 and had to be euthanized; tests later determined she had squamous-cell carcinoma, a type of cancer. In 2016, a 1-year-old female named Asha who had just been transferred to Toledo was euthanized after falling and breaking a leg beyond repair.
Dr. Michels said all four cases are notably different.
Nothing now indicates that any of the giraffes was affected by something like a soil contaminant, as that would have appeared in test results, Dr. Michels said. None of the other species of animals in the Africa! exhibit, including some that would be much more susceptible, have shown any signs of such exposure either.
There is likewise no evidence to suggest that romaine lettuce visitors give giraffes from the feed deck, including any residue from sunscreen or other substances on their hands, has affected the animals in any way, the veterinarian said.
“The giraffe feed deck has been instrumental in conditioning Tuli, Binti’s mother, to allow us to draw blood,” Dr. Michels said. “Giraffe are cautious animals, often not allowing for voluntary blood draws. We are continuing to monitor the giraffe for signs of anemia and have iron supplements on hand in case treatment is needed.”
He added that Trevor was “overly cautious” and would not allow voluntary blood draws. Binti was actively being trained for blood draws when she died.
Mr. Bekker noted that the Toledo Zoo is not alone in its experiences with giraffe deaths. Other zoos, including the Columbus Zoo in late 2018, have had multiple giraffes coincidentally die within short time periods.
“This isn’t unique to us,” he said. “We’re not seeing anything abnormal.”
Multiple attempts to obtain comment from the AZA were unsuccessful. But Mr. Bekker provided statistics from the association that show that of all giraffes — not taking into account specific subspecies — in its accredited institutions, 24 percent don’t live to reach age 1.
“A lot of those offspring are actually stillborn or failure to thrive,” Mr. Bekker said.
The Toledo Zoo has had three such calf deaths in recent years: a stillborn female in 2008, a male that died at 1 day old in 2013, and a female that died at 2 days old in 2017.
Of those giraffes that reach their first birthday, the median life expectancy for females is 19.4 years and 13.4 years for males, according to AZA figures. Thirty-seven percent of male giraffes die before their third birthday. The AZA does not track that statistic for females, but there is no significant difference in mortality rates between the sexes, Mr. Bekker said.
Mr. Bekker said though it isn’t specifically tracked, mortality rates for the Masai giraffe are generally a little higher than for giraffes as a whole.
A 12-year-old male named Mowgli at the Toledo Zoo was euthanized in 2012 because of a chronic hip issue. A female named Zahara, born in Toledo in 2005, was euthanized at 3 years old at the Louisville Zoo after being found down and unable to stand. She had a history of neck problems and a necropsy confirmed a pinched spinal cord.
Toledo-born female Akilah, 4, died in 2010 at the Cincinnati Zoo. She was found with her horns tangled in netting in the enclosure and a necropsy ruled she died from a collapse of the cardiovascular system stemming from shock.
Meanwhile, 10-year-old Enzi, a male born in Toledo in 2009, is alive and well at the Columbus Zoo, as is 2-year-old Kipenzi, born here in 2017, at the Seneca Park Zoo in Rochester, N.Y.
Mr. Frushour said any time an animal dies at the Toledo Zoo, particularly when the reason is unknown, staff reviews the animals’ environment, diet, and overall care as well as general policies and procedures. Staff has walked through the Africa! exhibit and inspected all of the plants and other features inside and has found nothing that might have caused problems.
The zoo has also consulted with other facilities to brainstorm and ensure its operations are in line with current best practices.
“We’re always looking at it any time something like this happens,” Mr. Frushour said. “We have a really good collaborative and proactive way of doing things. We are constantly trying to be at the pinnacle of animal care and when something like this happens, it hits hard.”
Because of the issues with mortality, Mr. Frushour said, the zoo has decided not to breed its three remaining Masai females: 18-year-old Michelle, who also goes by Charlotte; 16-year-old Elli, and 8-year-old Tuli. It will instead focus on acquiring reticulated giraffes for its program.
Mr. Frushour said it will not be an issue to have individuals of the two subspecies together as the zoo can prevent any cross-breeding. And visitors will be able to see some of the differences between the two, like the patterns on their coats.
“I think it will be a cool experience to be able to see the two species together,” he said.
First Published August 31, 2019, 9:33 p.m.
