latest update has some interesting speculation on cubsleep:

Update February 7, 2010 8:30 PM CST
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Today at 8:43pm
The video** captured by Linda Gibson at 1 AM gave us the earliest opportunity we have ever had to watch a cub sleep. A high percentage of the sleep was active (REM) sleep. Every time we thought the cub was in quiet non-REM sleep, it would jerk, twitch, flex a paw, or vocalize. Any dreams must have been pleasant because it even gave the contented motor-like hum at times. Sleeping adult bears sometimes make this same sound.

We checked Google for REM sleep in infants and found http://www.askdrsears.com/HTML/7/T070200.ASP , which may or may not be a scientific site. It said infants have about 50% REM sleep compared with only 20% for adults and that REM sleep may promote brain development. It said premature infants have an extra high proportion of REM sleep—about 90%. We thought the cub was showing a proportion close to that. Maybe that’s not surprising considering the premature state of newborn cubs and their need for rapid brain development to follow mom from the den about two months from now.

The good sighting of the cub on mom’s back is a harbinger of sightings to come as the cub gets more fur and the weather gets milder. During the sighting the temperature was 12-14 F above zero.

During the day, with temperatures as high as 25, Lily was good enough to pull her head out from under her chest and reveal her face and radio-collar to any newcomers who had not seen that before. Signals from the collar led us to her den and let us find her and walk with her when she is out of the den and active in summer. Last fall, she was good enough to let us put this new collar on without tranquilizers, showing the same trust that allowed us to put the camera in the den without her getting defensive or abandoning the den. We’ll see how long she keeps the collar on in the den. Now, 4 months into hibernation, she has lost considerable weight, and the collar could slip off. She is a remarkable bear that is giving all of us a better understanding of how bears live.

Thank you for your donations that will make more of this possible.

—Lynn Rogers and Sue Mansfield, Biologists, North American Bear Center

I know not the greatest picture. BUT I GOT TO SEE HERjumping up & down, Her cute little feet

great job!! its hard to snap pictures in that lighting condition + fog + wiggly cub!!!

Update February 8, 2010 8:00 PM CST
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Today at 8:26pm
More on misconceptions. We often hear that bears hibernate for 5-7 months without eating, drinking, urinating, and defecating. Some may do that, but the statement is a simplification.

It’s true most don’t eat. In northeastern Minnesota, there’s nothing to eat except the pads of their feet. In mid to late winter, they shed their calloused old pads and sometimes ingest them. From that comes the Native American legend that bears crush berries into their foot pads all summer as they cruise their ranges, and then survive overwinter by sucking the essence of berries out of the pads, even consuming the pads themselves. We do find pieces of foot pads in fecal plugs near dens, so who can say the legend is wrong?

What is a fecal plug? Another legend written in supposedly scholarly books states that just before hibernation, bears eat roughage to make a fecal plug to prevent further feeding. A fecal plug does form in the colon, but it’s at the wrong end to prevent feeding. The fecal plug is nothing mysterious. Just like starving people, bears continue to make feces even though they are not eating. Where does the fecal plug come from? Intestinal cells slough off during winter and accumulate as feces. Roughage in the feces matches the bedding in the den and includes some hair. They undoubtedly ingest some bedding accidentally as they rearrange it, as you have seen, or as they rake it into the den in fall (or in winter as we saw Lily bring in branches and bite them into smaller pieces for bedding). They also groom in the den which would account for hair in the fecal plug.

As far as drinking goes, there is no water available in the frozen north, but some bears eat snow. Fat metabolism also provides water, and metabolic water may be enough for some bears. Just about everything a person might say about a bear falls under a bell shaped curve. Most bears would fall in the middle of the curve, but some are out in each tail. So there are exceptions to much of what a person might say.

Do they urinate in winter? Probably most do not, according to captive studies, and that topic leads into more wonders of hibernation for another update.

—Lynn Rogers and Sue Mansfield, Biologists, North American Bear Center

Update February 9, 2010 10:50 AM CST
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Today at 11:01am
How clean is Lily’s den and how does it smell? Yesterday, we mentioned the fecal plug. Some bears make less feces than others and can wait until emergence in spring to evacuate the plug, thus the statement that hibernating black bears can go all winter without defecating. But some bears can’t wait that long. Among them are near-term mothers who have pressure on the colon. After nearly four months of hibernation, they have a build-up of feces in the colon by late January. None of the bears soil the bed. If it is a short den entrance like Lily’s, they have to exit. If it is a long den entrance, we find the plug frozen near the entrance.

How does a black bear den smell? Clean and fresh. The smell is different than an empty hole. A person can sniff the entrance of a suspected den and tell if it’s just earth or a bear in there. But the light odor is pleasant, at least to us with a bias for bears. Mothers have been eating and recycling the nutrients evacuated by cubs. She’s been licking the cubs clean. She has not been soiling the den herself. There are no remains of food. Her breath is clean and fresh. It’s clean enough to crawl in and curl up.

So why do many people think bears stink? Another misconception. Occasionally, bears roll in smelly substances. In mating season (May-June around here), mature males have a musky odor on the crown and back of the neck—the parts they rub on trees to leave scent. Bears can have bad breath if they were hungry enough to eat carrion, but usually they eat fresh berries, nuts, vegetation, and insects and have perfect breath.

Do we dare reveal how strong our biases are for bears and say that we don’t think their feces stinks? It’s true. Unless they’ve been eating meat or a lot of insects, summer scats smell more like the berries they’ve been eating than anything else. It’s not totally a berry smell because of some fermentation, the bile, intestinal cells, and digestive fluids, but the berries come through as a dominant odor. The non-foul odor of most scats is good for us because scat analysis is part of bear research. During our Black Bear Field Courses here, people are shocked when we pick up a piece of scat and smell it to see what the bear has been eating. They’re surprised when they smell it themselves and find it’s nothing like they expected.

How can you find a better animal than that?
Thank you also for the names you are submitting. With over 3500 entries already, we’re learning a lot about the meanings of names to use long into the future, if not for Lily’s cub.

Tomorrow: mother-cub bonding.

—Lynn Rogers and Sue Mansfield, Biologists, North American Bear Center

Jwnix, thanks again for posting all the updates, I read them daily. I really have learned a lot about the black bear, since our precious Lily.

You are most welcome! Glad to know someone is reading them!!

My hope is more people will join in the conversation here, and in conservation threads about bears so we can all become more 'bear aware".

There are numerous bear sites where one can obtain information.... I have one in my signature line.

They are majestic animals and we must protect their habitat!!! And, for those of us lucky enough to live where they do, we must be careful to remember they are wild animals!!!

Update February 10, 2010 5:58 PM CST

We have a lot to learn about mother-cub bonding. We’ve never been able to watch a mother and cub like this before.

When the cub was born, we didn’t know what to expect. Lily surprised us with immediate sweet grunts that mothers use only when they are concerned about a cub. She made those sounds even before the cub cried. We believe Lily immediately bonded with the cub at birth. It's hard to imagine a better mother than a bear in a den. She's totally invested, dedicated, protective, predictable, and comforting. She has nothing else to do but snuggle and nurse the cub 24/7. She responds to each cry. Are there different cries for hungry, wet, cold, tired, potty time, over-stimulated, or need for closeness? We don’t know. Does the cub have emotional needs at this point, or are the needs purely physical? Hard to tell.

Does mother and cub become imprinted on the smell of the other? For animals with such legendary senses of smell like bears, one would think so. But we wonder. Mothers in dens will suckle and care for any cub. Mothers have such strong mothering instincts that they will adopt strange cubs that are left at entrances of dens. They're not like herd animals that are particular to give their milk only to their own young which they recognize by smell. Hibernating bears evidently have never been subject to natural selection for that trait. A mix-up in cubs would be impossible while they are still in dens. A few days or weeks after leaving the den, mother bears become more selective.

Cubs may be especially prone to bonding between the time their eyes open at 6 weeks and the time they leave the den at 12 weeks. Like puppies, captive cubs that are removed from their mothers during that period readily bond with humans that bottle-feed them. If a cub is raised by people during that period and then given to a wild mother for adoption, it can be difficult to get the cub to accept the new mother. Biologists who tranquilize mother bears in dens see changes in cub acceptance when the cubs approach 5 pounds and are about to emerge at 10-12 weeks of age. When biologists pick up younger cubs and tuck them into their jackets against their chests for warmth, the cubs are content. Some even make the motor-like hum. But if the biologists go to dens when the cubs are nearly ready to emerge, the cubs are no longer trusting. They greet the biologists with screams, bites, swats, and claws.

We wish we knew what is going on in the heads of Lily and the cub. What emotions do they feel? We wish we knew the meanings of the different cries. When the cub becomes more visible, it might be easier to tell.

—Lynn Rogers and Sue Mansfield, Biologists, North American Bear Center