A mystery is gnawing at the branches of the rescued Willard Bay beavers' family tree.
Beaver No. 6 is likely related to No. 5 -- but is he also related to No. 2? Are No. 3 and No. 1 siblings? Is Momma the mother of two of the juveniles, or all five of them -- or none of them?
DNA testing may be able to sort out the relationships of the six animals injured in a recent diesel fuel spill at the bay and now recovering at the Wildlife Rehabilitation Center of Northern Utah.
Knowing how or if the animals are related would help as the center plans to integrate the beavers into common housing and eventually return them to the wild, said executive director DaLyn Erickson-Marthaler.
In the wild, beavers live in family units. The goal is to release the six Utah beavers together, but if the mother doesn't accept all of the juveniles, the animals may need to be broken into two groups.
Yes, it's rare, but DNA testing has been done on beavers by an Arizona laboratory, and Erickson-Marthaler says her Ogden wildlife center has contacted folks there -- and also at the University of Utah -- about whether the Utah beavers could be tested.
As volunteers attempt to introduce the five juveniles and one adult to one another, she said, "It would be nice to know Mom's mom to everybody and we have no worries."
However, the odds are "astronomical" that a mother beaver could raise five kits to the age of 1, the estimated age of the young rescued animals, Erickson-Marthaler said, because mothers can nurse only four babies at one time.
"But," she added, "never say never."
The lab that researched beaver genetics is located at the University of Arizona in Tucson. Erickson-Marthaler said the wildlife center submitted an inquiry to the facility about the possibility of identifying DNA and just heard last week that the testing could be done, but will take four months.
"Four months would be too long for our needs," she said, explaining that if the beavers can be released this summer, they need to go out early enough to prepare a lodge for winter. So, she said, the center is asking the university if the process can be expedited.
A wildlife center volunteer who works in a genetics laboratory at the University of Utah is also checking into DNA testing of the rodents there, Erickson-Marthaler said, so "we may be keeping it in state."
The beavers arrived at the center in March in different waves and are numbered in the order they arrived. Nos. 1 and 2 were found together and may be siblings; No. 3 was rescued two days later and may be related to the first two animals.
The next three beavers -- a mother and two kits -- were found more than a week after the spill and are thought to be a family, Erickson-Marthaler said.
As they've cared for the injured beavers, volunteers at the Wildlife Rehabilitation Center have networked with other facilities across the country with expertise with the large rodents.
But the Ogden center is also paving new ground in the data it is collecting, because the situation and injuries related to the Willard Bay spill have been unique, Erickson-Marthaler said.
"Eventually, we'll publish a paper on this," she said.
One thing the director has discovered, for example, is that adding human baby food to a nutritional supplement for the herbivores makes the gruel more tasty.
And then there's an animal relaxation technique Erickson-Marthaler discovered by accident, as she treated the beavers during bathtub sessions. Supporting the animal's jaw just so and stroking the sides of its face seems to have a calming effect.
"It almost puts them in a hypnotic state," which allows Erickson-Marthaler to look inside their noses or mouths, or lance abscesses on their skin.
"It's kind of a handy trick to learn," she said. "I can get away with a lot of stuff."