Edward, a 2-year-old wolverine at San Francisco Zoo & Gardens, is seeing better thanks to a first-ever corrective procedure on a wolverine’s eye. Following a recent cataract surgery, he became the first wolverine to have a custom-made intraocular lens implanted in his left eye.

Born at Billings’ ZooMontana in 2023, Edward was transferred to San Francisco Zoo later that year. While wolverines are generally solitary predators in the wild, Edward now enjoys the company of his female companion, Molly. In May 2025, the 30-pound male wolverine’s caretakers noticed his right eye was cloudy and informed the Zoo’s veterinary team.

“We were surprised to see what appeared to be a cataract forming in the eye of such a young animal,” said Dr. Nick Dannemiller, clinical veterinarian at the Zoo and board-certified specialist in zoological medicine. “So, we called an ophthalmologist to further evaluate Edward’s condition.”

Dr. Kate Freeman is no stranger to treating exotic animals. The board-certified veterinary ophthalmologist holds a Master’s degree concentrating on marine conservation and ecology, and her focus in veterinary school was zoo/wildlife animals, with the initial intention of becoming a wildlife veterinarian. Beyond her practice at the nearby Veterinary Vision, she also works as a veterinarian at The Marine Mammal Center in Sausalito and routinely travels to a handful of animal facilities to care for the eyes of various exotic animals and wildlife.

Dr. Freeman officially diagnosed a mature cataract in Edward’s right eye in June and noticed a small cataract forming in his left eye. A successful surgery to remove the cataract in the right eye was performed in August.

“In a cataract surgery, the contents of the lens, that normally refract light to the retina, are removed because they have become clouded, obscuring vision,” said Dr. Freeman. “In humans, and even in cats and dogs, there are manufactured replacement lenses made specifically for those species. At the time of Edward’s first surgery, there were no artificial lenses made for a wolverine.”

Edward was left without a replacement lens, leaving him farsighted in his right eye – unable to see close up.

Realizing that Edward would eventually also need cataract surgery on his left eye, Dr. Freeman was determined to find a solution for him, knowing he would not do well being farsighted in both eyes. She turned to an old mentor, veterinary ophthalmologist Dr. Christopher Murphy, professor emeritus at the UC Davis School of Veterinary Medicine, where Dr. Freeman completed her comparative ophthalmology residency in 2012.

Dr. Murphy, in turn, called an old friend and colleague, (human medicine) optometrist Dr. Donald Mutti, professor at The Ohio State University College of Optometry.

“Dr. Murphy and I have worked together for many years calculating the intraocular lens measurements for various birds – a falcon and an eagle,” said Dr. Mutti. “I wasn’t about to pass on a wolverine case. Even though I’m a loyal Buckeye, I just couldn’t leave an innocent wolverine in the lurch,” continued Dr. Mutti, referencing the Ohio State and Michigan mascots and the heated rivalry between those two universities. “Everyone deserves good vision.”

That’s right, a Buckeye was about to help a wolverine!

“The amount of farsightedness in Edward’s eye without an implant would be extremely high,” said Dr. Mutti. “A high level of farsightedness in a person is about 10 diopters, units of optical power. My guess is that Edward was at about a level of 50 diopters, where he’d be able to see whether lights were on or off and maybe some gross motion, but there would be no capability for detail vision in Edward’s eye.”

The three vision specialists got to work calculating the specific measurements for a custom-made lens for Edward. Based on ultrasound images of Edward’s eye and corneal measurements using a keratometer on loan from Micro Medical Devices, they were able to analyze and calculate the corneal curvature, size of natural lens, length of the eye, and where the lens would sit following surgery. After many different calculations, and consultation with the lens manufacturer, an-vision, the team settled on an optical power of 100 diopters for Edward’s lens and had the lens created. In comparison, cats are 53.5 on the scale, and dogs are generally 41 diopters. The optical power for human lenses varies based on individual calculations.

“Based on the measurements we calculated, a dog or cat lens would not work well for a wolverine, so we elected to have a special one made for him,” said Dr. Freeman.

In November, Edward underwent a second cataract surgery, this time on his left eye. Dr. Freeman successfully implanted the custom-made lens into that eye. It was determined best to leave the right eye without a replacement lens as that eye was doing very well and wolverine eyes are sensitive to procedures.

“Every time you open up an eye, you introduce potential problems,” said Dr. Freeman, explaining why a lens was not placed in his right eye also. “Since we knew Edward was doing well with only one eye farsighted, it was best to leave the right eye aphakic (without a lens).”

The world’s first wolverine to have a corrective intraocular lens implanted in his eye is doing much better according to his care team.

“Before the first surgery, he was very mistrusting of doing anything on the right side of his body,” said Dr. Dannemiller, about evaluating Edward’s vision. “After the surgery, we believe he can see a bit better, albeit aphakic, because he was more willing to present his right side during training activities. And now after the second surgery, we notice improvements in his overall vision.”

Edward now receives eye drops two to three times a day. Thanks to exceptional training by his handlers, he voluntarily receives the drops.

Edward’s improved vision was noticed recently when he successfully out-hunted Molly to catch a small rodent that naturally appeared in his exhibit, so his care team is encouraged by the success of the surgery.

While Edward eats a wolverine’s natural carnivore diet (rabbits, poultry, etc.), the random rodent was an anomaly – he does not have to hunt for his food normally. He does, however, enjoy one peculiarity in his diet – he is quite fond of taco seasoning.

“He can’t get enough of it,” said Dr. Dannemiller. “He loves taco seasoning on everything. Even if you sprinkle a little in his habitat, he will tear through the exhibit trying to find it.”

Going forward, Dr. Freeman and the Zoo will continue to monitor Edward’s vision and expect him to live a normal life.

Dr. Dannemiller approximates that wolverines typically live 5-10 years in the wild and up to 15-20 years under human care. Currently, there are only about 30 wolverines at zoos and wildlife centers in North America. Wolverines are listed as a threatened species under the Endangered Species Act, primarily due to climate change and habitat loss, with an estimated 300 individuals remaining in the contiguous United States.

As for this Saturday’s Ohio State-Michigan football game, we presume Edward will be rooting for the Michigan Wolverines, but he may now have a soft spot for the Buckeyes after receiving their help.

A beloved female chimpanzee named “Twiggy” will soon be departing her home at San Francisco Zoo & Gardens to join the chimpanzee troop at the Maryland Zoo in Baltimore. She was deemed a good fit as this will allow her to build more relationships with other females, including one she is already familiar with. With this move, the Zoo announces that it will temporarily place the chimpanzee program on hiatus, with the future transfer of the remaining chimps to another zoo.

“In professional zoos, individual animals may transfer to another facility based on an Association of Zoos and Aquariums’ Species Survival Plan for Chimpanzees (SSP) recommendation,” said Robbie Graham, Senior Curator of Mammals. “Twiggy has become a favorite among staff and guests here, but when a request of this nature comes in, we want to do what is best for the animal.”

Twiggy, now 39-years-old, was transferred to SF Zoo in 2019 along with another female and male to form a larger troop with the opening of the new habitat, Great Ape Passage. Twiggy, renamed “Connie” as her public-facing name after a special donor, was part of an effort to expand the chimpanzee group, which had long been comprised of senior chimpanzees, “Minnie,” “Maggie” and “Cobby,” who each lived at the Zoo for more than 40 years. In addition to the two females and male, a fourth male transferred to the Zoo, based on an SSP recommendation.

Integrating adult chimpanzees together is complex, and it was necessary to find suitable individuals within the accredited zoological community that needed a new home. To do this, the SSP management group needed to find chimpanzees projected to be the most compatible with the Zoo’s troop, reviewing behavior profiles of potential new group members to find the best fit.

In the case of the two new females, including Twiggy, assimilating with senior chimps Minnie and Maggie served as an incredible display of acceptance of new troop members. The male introductions also exceeded expectations, as the new male “Gombus,” was the first other male chimpanzee ever to join this particular troop, and both Cobby and Gombus were patient and at ease, helping the integration process succeed.

The passing at 61 of Cobby in 2021 of old age, as the oldest male chimpanzee living under human care, followed in 2024 of female Minnie at age 54, and this year, of Maggie at age 55, the remaining three individuals – Twiggy, Gombus and Michael – coped with the losses of the senior members of their troop.

“Every loss was devastating, to not only long-time chimp caretakers, Zoo staff and those who grew up with them in San Francisco, but also to the remaining chimps,” said Graham. “We honor those we lost, but we also wanted to better understand what was best for the smaller group.”

With the recommendation to move Twiggy to Maryland Zoo, primate staff saw her departure as an opportunity to make an important decision – to temporarily halt the chimpanzee program, and focus on another Great ape species, the critically endangered Bornean orangutan. Currently, the Zoo has a male and female, and after the Zoo finds a home for the bonded males, Gombus and Michael, the chimpanzee habitat can be converted to house orangutans.

“We have an opportunity to create a mixed species habitat for both orangutans and endangered white-cheeked gibbons,” said Graham. “The plan would be to bring in another female orangutan, and participate in the Species Survival Plan for Orangutans’ breeding program. We are excited about this, as time is ticking for orangutans, as one of the world’s most critically endangered species.”

And within a few years, the hope is the return of chimpanzees to San Francisco.

“When the time is right, we want to build a multi-generational chimpanzee habitat, and continue the long tradition of raising awareness about one of the most iconic species in the world.”

A date for Twiggy’s departure has not yet been scheduled.

The public is invited to see San Francisco’s newest resident, Cecil, a 26-year-old male silverback Western lowland gorilla, who will make his official public debut on Saturday, October 18^th. Cecil arrived at San Francisco Zoo & Gardens in early August from the Louisville Zoo in Kentucky, to start the acclimation process, which also included an introductory phase with the Zoo’s resident females.

“We are excited for the public to see Cecil in his new home and among his new family troop,” said Robbie Graham, Senior Curator of Mammals. “Since his arrival, we have found him to be very even-tempered, and almost ‘chill’, as experiencing an all new environment among all new caretakers and other gorillas might have otherwise been daunting.”

Last April, silverback Oscar Jonesy, who led the Zoo’s family troop since 2004, passed away from advanced heart disease. Soon after, the Association of Zoos & Aquariums’ (AZA) Species Survival Plan (SSP) for Gorillas, which manages all 350 gorillas living in AZA-accredited facilities, identified Cecil as a promising candidate to lead a family group, as his genetics offer a strong match for the Zoo’s female members.

Through managed breeding and deep understanding of natural behavior, the Gorilla SSP aims to maintain a genetically healthy gorilla population for the next century, while raising public awareness about gorilla conservation and the threats faced by wild populations of this critically endangered species. SF Zoo participates in both the Gorilla SSP and Gorilla SAFE (Saving Animals From Extinction) programs.

Born at the Cincinnati Zoo in 1998, Cecil moved to the Louisville Zoo in 2004, where he was part of a young bachelor group. Bachelor groups are a common social grouping modeled after wild gorilla behavior, allowing maturing silverbacks to develop socially, physically and hormonally.

The process of introducing our resident females, 45-year-old Bawang, 27-year-old Monifa, and 20-year-old Kimani, to a new silverback, is a complex process that takes time, patience, careful planning and observation by primate specialists. The process takes into consideration each individuals’ personalities and social history, and social dynamics.

“We allowed the gorillas to do things on their own time,” said Graham. “And because Cecil is still considered relatively young, we gave him space to explore his outdoor habitat on his own, before meeting each of the females as a group.”

“The arrival of Cecil is a welcome one, not only for our gorilla family, but for the City of San Francisco,” said Cassandra Costello, Chief Operating Officer and Interim Co-Chief Executive Officer. “From the excitement I hear from the community, we know that visitors will come specifically to see him, as he takes reign of his new family troop.”

Guests can see Cecil at the Jones Family Gorilla Preserve at SF Zoo daily. Hours of operation are 10 a.m. to 5 p.m., winter hours are 9:30 a.m. to 4:30 p.m., beginning November 2.