Ultrasound: Idaho Falls sloth bear is pregnant

The Tautphaus Park Zoo’s female sloth bear is pregnant, but finding that out took some innovation from zoo workers.

According to a news release from the City of Idaho Falls on Wednesday, zoo staff performed an ultrasound on 370-pound Pria on Friday without any anesthesia or physical restraint.

The keepers cut out a small access portal in the mesh in Pria’s enclosure. Then they trained her to sit with her abdomen up against the opening. The keepers trained Pria to let them shave her belly for the procedure. To help her steady herself, the keepers created a sleeve that also sits on the outside of the enclosure. Another access portal was cut in the enclosure mesh so Pria could extend one of her forearms into the sleeve and grasp a rod in the sleeve with her claws, thereby increasing her ability to pull herself forward and hold herself steady. Dr. Sarah Herres of the Idaho Falls Veterinary Emergency Clinic then placed the ultrasound probe on Pria’s belly, allowing for visual confirmation of the pregnancy. Meanwhile, Pria sat calmly, being rewarded with peanut butter or honey, the city said.

“We saw a spine, ribs and a heartbeat,” said Beth Rich, the zoo’s superintendent. “As far as we know, this is the first time a pregnancy ultrasound has ever been done on a sloth bear without anesthesia.”

It is unknown from the ultrasound when the cub or cubs – sloth bears usually give birth to twins – will arrive.

Sloth bear breeding season ranges between May through August. At the Tautphaus Park Zoo, Pria and Mick, the zoo’s male sloth bear, bred in July. Like all bears, sloth bears have delayed implantation, which means that even when an egg is fertilized, it may not implant and start growing right away. Gestation is generally around six to seven months.

Two infrared cameras with microphones set up in the birthing den so zoo staff can watch events from outside the den and not disturb Pria.

Newborn sloth bear cubs weigh less than a pound. They are born blind and cannot walk. The mother has to hold them to keep them warm, clean and to nurse them.

“Even though we’ve determined Pria is pregnant, we’re not out of the woods yet.” said Rich. “Sloth bear cubs are so small when they’re born and so dependent on their mother for everything, there’s always a chance that they may not make it. We’ll do everything in our power to set Pria up to succeed and we will give her every chance to be a good mother to the cub(s). But we will hand raise them if needed.”