Technician Spotlight: Jessica Brekke’s “Rat Hammock” Design

The heart of any laboratory animal facility is its animal care staff. Dedicated and compassionate animal care technicians can make a tremendous difference in the quality of the animals’ lives. One such committed individual is Jessica Brekke, registered laboratory animal technician working at the Mayo Clinic campus in Rochester, Minnesota.

Brekke is always on the lookout for new enrichment ideas to use with the animals in her charge. Not satisfied with the wood gnaws and paper twists available to the rats she worked with, she searched online for other items with which the rats could interact. She came across a mouse swing, which she thought would be ideal because rats like to climb; a swing would also not take up valuable cage floor space. To Brekke’s surprise, she could not find anything similar that was designed for rats. “This got my wheels churning,” said Brekke. She took thick cardboard tubes that were already used with rats at her facility and cut them in half lengthwise. She then drilled a hole into each corner and inserted shower curtain hangers to suspend the resulting “rat hammock” from the wire lid. After getting the green light from the facility veterinarians, Brekke tried out her invention with the sentinels (animals in a lab who are not used in research projects, but who are closely monitored to quickly identify any potential pathogens in the colony). “Within two minutes, both of the rats were climbing onto it and checking it out; when I came back later that day, I found them both sleeping together in the hammock,” she said. “I spent the next week observing the way they interacted with the hammock and found that they would not only sleep in it, but also groom themselves, play, take and eat treats, and look out at their neighbors and activity in the room.” 

Satisfied that rats seemed to like the hammock, Brekke updated the design to be more durable and more cost effective. The shower curtain hangers caused the hammock to swing too much when the rats played in it, so she replaced the hangers with 6-inch pieces of 16-gauge galvanized steel wire. She replaced the cardboard tubes with 3-inch diameter, 6-inch long sections of PVC pipe. With her dad’s help, Brekke used a table saw to cut the PVC pipe, a drill to make holes in each corner, and pliers to attach the wire. She and her son used a belt sander to smooth any jagged or sharp edges on each piece of PVC and wire. Hammocks were cleaned in the cage washer. 

Brekke obtained veterinarians’ approval for the new design, and the principal investigators’ permission to try them out with their animals. All rats started to use the hammocks within the first day, and used them in the same way as the sentinels: to sleep, groom, play, and look out. “The feedback from the investigators was positive,” said Brekke. “They like the new form of enrichment and they said the rats seemed to enjoy having an elevated platform.” 

The hammocks have become an unofficial part of Brekke’s enrichment program for rats. She uses the hammocks with the sentinels and with rats on active protocols, as long as the rats’ health status allows them to use the hammocks safely. We applaud not only Brekke for her creativity and dedication to animal welfare, but also her facility for supporting its animal care staff in their endeavors. 

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