# Ursine Uptime (DD-681)

> 'Walking hibernation' is a real term. The North American Bear Center describes it as the 2-3 weeks after bears leave the den, when they move around but eat and drink less than normal while their bodies return to summer levels. In a 2011 Science study, Øivind Tøien and colleagues continuously monitored black bears (Ursus americanus) in Alaska. They found the bears cut their metabolism to about 25% of the basal rate while body temperature fell only modestly, cycling between about 30 and 36 °C. Heart rate dropped from about 55 to as few as 9 beats per minute, and metabolism stayed reduced for up to three weeks after the bears emerged. Studies of brown bears in Sweden found body temperature normalized about 10 days after emergence, and heart rate took about a month. Black bears in closed dens go 5-7 months without eating, drinking, urinating or defecating, but mothers in open dens may lick meltwater and clean up after cubs.

- Department: Nature (also Science)
- First published: 2025-12-18
- Last updated: 2025-12-18
- Permalink: https://detailenjoyer.com/case/ursine-uptime/
- Author: Marcus Easterling (DetailEnjoyer), The Detail Department

## Quick facts

- **DD-681-F01**: After leaving the den, bears stay in 'walking hibernation' for about 2-3 weeks. _(Write-up · Exhibit A (Walking hibernation))_
- **DD-681-F02**: Black bears cut metabolism to about 25% while lowering body temperature only about 5-6 °C. _(Write-up · Exhibit B (Metabolism without the chill))_

## Write-up

Awake but still hibernating. Bears' metabolism stays low for weeks after they leave the den.

1. **Walking hibernation**: For about 2-3 weeks after leaving the den, bears are up and moving, but their metabolism is still adjusting. They voluntarily eat and drink less and excrete less than they will later in the year.
2. **Metabolism without the chill**: Tøien's black bears cut metabolism to about 25% of basal rates but lowered body temperature by only about 5-6 °C, cycling between about 30 and 36 °C in multi-day rhythms.
3. **A slow heart**: Heart rates fell from about 55 to as few as 9 beats per minute, with pronounced arrhythmia during breathing pauses.
4. **No food, water or waste**: Bears in closed dens go 5-7 months without eating, drinking, urinating or defecating. Mothers in open dens may eat snow and clean up after their cubs.
5. **The slow restart**: In brown bears studied in Sweden, body temperature normalized about 10 days after emergence and heart rate took about a month.

## Related case files

- [Shark Senescence (DD-701)](https://detailenjoyer.com/case/shark-senescence/): Another animal with an extraordinarily slow metabolism
- [Turtle Torpor (DD-683)](https://detailenjoyer.com/case/turtle-torpor/): Another case about slowing down to survive
- [Amazing Bear Ability (DD-177)](https://detailenjoyer.com/case/amazing-bear-ability/): I linked more about bears
- [Bdelloid Rotifers (DD-641)](https://detailenjoyer.com/case/bdelloid-rotifers/): Another animal that waits out hard times

## Reel vs. record

- **Note**: Body temperature doesn't 'drop dramatically': black bears lower it by only about 5-6 °C, cycling between about 30 and 36 °C. The big drop is in metabolism, to about 25% of basal (Tøien et al., 2011).
- **Missing numbers**: heart rate falls from about 55 to as few as 9 beats per minute.
- **Missing duration**: walking hibernation lasts about 2-3 weeks, when bears voluntarily eat and drink less (North American Bear Center).
- **Not universal**: bears in closed dens go months without eating, drinking or excreting, but mothers in open dens may lick meltwater, eat snow and clean up after cubs.
- **Unidentified bear**: the pale bear in the footage isn't identified. The physiology figures come from wild black bears (Alaska) and brown bears (Sweden).

## Video: Ursine Uptime: Awake but Still Hibernating

- Duration: 17.9 s · Published: 2025-12-18
- File: https://detailenjoyer.com/assets/videos/DSbGOa8kUE0.mp4

### Transcript

DID YOU KNOW? When bears come out of hibernation in early spring, they enter a transition phase called "walking hibernation", where their metabolism is still slow, and they gradually regain full strength. During hibernation, a bear's heart rate, body temperature, and calorie use drop dramatically, allowing it to survive months without eating, drinking, or expelling waste. NOW YOU KNOW!

## Questions & answers

**Q: What is 'walking hibernation'?**  
A: About 2-3 weeks after emergence. _(Source: Write-up · Exhibit A (Walking hibernation) · North American Bear Center: 5 stages of activity and hibernation; Tøien et al. (2011), Hibernation in black bears: independence of metabolic suppression from body temperature, Science (PubMed))_

**Q: Black bears cut their metabolism to about what share of basal rates?**  
A: About 25%. _(Source: Write-up · Exhibit B (Metabolism without the chill) · Tøien et al. (2011), Hibernation in black bears: independence of metabolic suppression from body temperature, Science (PubMed); EurekAlert! (2011): Bears uncouple temperature and metabolism for hibernation)_

**Q: About how much does a black bear's body temperature fall?**  
A: Only about 5-6 °C. _(Source: Write-up · Exhibit B (Metabolism without the chill) · Tøien et al. (2011), Hibernation in black bears: independence of metabolic suppression from body temperature, Science (PubMed); EurekAlert! (2011): Bears uncouple temperature and metabolism for hibernation)_

**Q: How low can a hibernating black bear's heart rate go?**  
A: As few as 9 beats per minute. _(Source: Write-up · Exhibit C (A slow heart) · Tøien et al. (2011), Hibernation in black bears: independence of metabolic suppression from body temperature, Science (PubMed); EurekAlert! (2011): Bears uncouple temperature and metabolism for hibernation)_

**Q: How long can black bears go without eating, drinking or excreting?**  
A: 5-7 months in closed dens. _(Source: Write-up · Exhibit D (No food, water or waste) · Tøien et al. (2011), Hibernation in black bears: independence of metabolic suppression from body temperature, Science (PubMed); North American Bear Center: 5 stages of activity and hibernation)_

## Sources

- [Tøien et al. (2011), Hibernation in black bears: independence of metabolic suppression from body temperature, Science (PubMed)](https://pubmed.ncbi.nlm.nih.gov/21330544/)
- [North American Bear Center: 5 stages of activity and hibernation](https://bear.org/bear-facts/5-stages-of-activity-and-hibernation/)
- [EurekAlert! (2011): Bears uncouple temperature and metabolism for hibernation](https://www.eurekalert.org/news-releases/664527)
- [Explore.org: Brown bears, spring emergence](https://blog.explore.org/brown-bears-spring-emergence/)

## Cite this case file

Easterling, Marcus. "Ursine Uptime." The Detail Department (DetailEnjoyer), case file DD-681, last updated Dec 18, 2025. https://detailenjoyer.com/case/ursine-uptime/