Grey wolf at Detroit Zoo dies during surgery to remove mass

The Detroit Zoo says an 11-year-old grey wolf has died during surgery to remove a mass in her chest.

Zoo officials say Wazi suffered cardiac arrest and died Monday. The mass had been discovered during a health exam, and veterinarians determined surgery was the only option because of its size and location.

The zoo says in a statement the wolf "was intelligent, fearless, curious and sassy," and "adored" by employees, volunteers and visitors.

The zoo's lone surviving wolf is a male named Kaska.