Before researchers from the Wildlife Research Institute videotaped 3-year-old June digging this den in Eagles Nest Township, Minnesota, they had no idea some bears made dens so early—July 19, 2004.  It was the first time researchers watched a bear dig a den.  The most interesting part happened when she encountered a 68-pound rock.  She did not make futile attempts to roll it up the steep incline of the entryway.  

(see video below) 

In 2003, the BBC phoned researchers for help with a documentary using new thermal imaging technology. The telephone conversation sounded something like:

BBC: “We’re looking for someone dumb enough to try putting tiny cameras under a mother black bear with cubs in a den. Do you have such a person?”

Researcher: “Will it have educational value that we can use at the Bear Center someday?

BBC: “Yes. One of the cameras will make the very first thermal images of heat loss patterns in dens.”

Researcher: “We have just the person.”