A poisonous timber rattlesnake bit two dogs in a Glastonbury backyard last week, officials say.

Robert Murray, the owner of the 3-year-old Vizsla and the 10-year-old miniature pinscher mix, discovered the snake.

The venom of a timber rattlesnake causes severe swelling and anaphylaxis. It is almost always fatal to dogs and cats without fast, aggressive medical care.

"When they came in, they both started to bleed and we could see the beginning of some swelling. We knew we didn't have much time,” he described.

He reached out to clinics in and out of state to get them antivenom.

After several calls, he was relieved to hear Pieper Veterinary in Middletown had a few doses on hand. The dogs, Tanner and Listo, were rushed there for treatment.

Medical director Dr. James Hammond says both dogs needed lifesaving measures including help breathing after the antivenom.

Listo’s face and neck were swelling so rapidly that it was closing off his windpipe, and he underwent an emergency tracheostomy.

Tanner and Listo were finally released from the hospital this weekend.

After the frightening experience, Murray has some advice for fellow pet owners.

"Be conscious, be listening, especially when you're talking about rattlesnakes. We also have copperheads in Connecticut, which are also poisonous."