King Cobra Now in Remission After Receiving Cancer Treatment

The 18-year-old reptile was given chemotherapy treatment through a pill that was placed in a dead rat's throat.

A king cobra is slithering in celebration now that he is in remission after it spent nearly a year battling cancer.

The 18-year-old snake, a resident of the Denver Zoo, was confirmed to have lymphosarcoma, a type of cancer affecting its scales, last February.

Associate veterinarian Betsy Stringer explained zookeepers were suspicious when they noticed purple scales on the unnamed snake and a biopsy of the abnormal scales confirmed it was cancer.

In order to run tests, including biopsies and x-rays, the king cobra went under anesthesia. Zookeepers were able to keep the 13-foot-long reptile asleep by keeping its head in a restraint tube hooked up to a gas anesthesia machine.

“Handling the snake is inherently dangerous,” Stringer told “He’s venomous, large and difficult to handle. We can’t easily get hands on him.”

After confirming the king cobra had cancer, Stringer worked with a veterinary oncologist at Colorado State University to come up with a treatment plan.

They decided to deliver chemotherapy every three weeks in the form of a pill that was placed in the throat of a dead rat that was fed to the cobra. Stringer said although delivering chemotherapy through an IV is the method preferred in humans, it would be difficult on a king cobra.

“I checked his blood work prior to each treatment to make sure he was responding to the drug and that it was safe to administer the next dose,” she explained.

But Stringer said the massive reptile kept its head up the whole time, and she didn’t notice a decline in his mood or appetite.

A December biopsy confirmed the treatment was a success, and the king cobra was officially in remission.

While the king cobra is close to the normal life expectancy of 20 years old, zookeepers were happy to buy him more time.