Females den before male black bears, and nuts move the date

STEP 1 · Den order

Adult females averaged 24 November

Ternent's GPS collar job report for the Pennsylvania Game Commission timed 26 dennings among 24 black bears in suburban Pennsylvania during 2010 to 2012. Those bears lived near Johnstown, Scranton and State College. Adult females went to dens first, with mean entrance on 24 November in both the abstract and the results. The mean for juvenile females was 10 December. Written results give adult males a mean of 9 December and juvenile males a mean of 31 December. Table 5 carries an entrance date for 10 adult females, 5 juvenile females, 4 adult males and 6 juvenile males. Those counts are our own tally of the dated rows. Class means use that tally. The table lists one adult female with no entrance date, and the pre-season figure below still counts her among its 11 adult females.

Adult females averaged 125 days denned and juvenile females averaged 104 days. Adult males averaged 109 days denned and juvenile males averaged 58 days.

Table 5 averages the same four adult males at 11 December. From the adult female mean on 24 November, 9 December is 15 days later and 11 December is 17 days later.

The earliest denning recorded was 26 October. She was a pregnant 8-year-old and later produced 3 cubs. Another adult female was still outside the den on 2 January. Before the hunting season, 4 of 11 adult females had already denned.

All classes denned earlier during 2010 than during the other years. Ternent called 2010 the poorest natural food year on the employee food survey. He wrote that the poor crop may have contributed to the earlier dates. An adult male denned on opening day during the 2010 season.

Ternent marked den entry on the day a collar first stayed still or quit transmitting. Our read flags a shed collar or a failed collar as able to pass for a den date. The same report says monitoring of 21 bears was disrupted because the bears shed the radio-collar.

The Pennsylvania Game Commission repeats that order in the 2024 to 2029 black bear plan. Pregnant females are described as typically denning first. Females with cubs born the previous winter follow, and so do juveniles of both sexes. Adult males den last and some stay active into January. Plentiful food delays hibernation in the plan and scarce food advances it. Pregnant females may start denning in early November. The plan says that start can come "before the statewide general firearms season." Across the 1980 to 2000 recovery the commission kept seasons later and many pregnant females were already denned. Cubs are born in the den during January's first three weeks. Implantation is timed between mid-November and early December.

The public species profile still expects pregnant females to den at mid to late November, with males several weeks later and earlier dates in poor food years.

STEP 2 · Catskill dates

Female medians led males by 16 days

O'Pezio and colleagues report medians for 35 black bears ages 1 to 17 in the Catskills from 1975 to 1979. Females with cubs show a median entrance on 22 November. Pregnant females show a median on 24 November. Barren females show a median on 30 November. The record covers 62 den arrivals and 38 departures. Females taken together show a median on 24 November. Males show a median on 10 December. That median trails the grouped female median by 16 days.

Autumn temperature differed among years, and so did snowfall and snow depth. Entrance dates still looked unrelated to those changes.

STEP 3 · Swamp dens

Mothers with cubs denned longer

Hellgren's dissertation followed 35 black bears through the winters of 1984 to 1987 in the Great Dismal Swamp of Virginia and North Carolina. Females made up 26 of them and males made up 9. Five bears kept moving for the full winter, and those five were 2 males and 3 females. Females with cubs entered dens sooner than the other groups and left later. They also denned longer, 119 days against 78 days for the other groups. That coastal plain fast is shorter than the denning of 104 female black bears in three Maine areas from 1982 to 1988. Each of those females spent 134 to 197 days denned.

STEP 4 · Nut crop

Scarce beechnuts advanced northern denning

The Schooley and colleagues abstract covers female black bears only. It follows 104 females in three Maine areas from 1982 to 1988. In two northern areas most females denned in the mid to late October period while beechnuts were scarce. Most denned in the mid to late November period in the abundant year after that. The authors wrote that the alternating pattern may have held for at least 11 years. Central Maine has less beech, and den entry there varied less across years. Pregnant females tended to enter dens ahead of other females. Year-to-year gaps in entrance were not strongly associated with the weather in autumn. In that conclusion, bears remain active until energy going out exceeds energy coming in. They hypothesized that pregnant females may den after fat reserves become adequate for reproduction.

Our read tracks that hypothesis. A pregnant female with enough fat for reproduction may quit while nuts are still available. A ridge can still show mast after that class has left. The Pennsylvania plan describes that same food link. Ternent's 2010 comment only suggests a link from one poor year in three suburban areas.

A single warm week does not clear the woods of bears. On 18 November 2025 the Michigan DNR bulletin gave Duquette's view. He thought most Michigan bears were likely still feeding in the warmth and seeking dens. He suspected Lower Peninsula bears were a few weeks out from denning, depending on weather. Snow and cold on the Upper Peninsula had already given some bears more reason to seek dens. The bulletin is one specialist's view of a single week. Neither peninsula gets a measured mean there.

STEP 5 · Late season

Late hunts still find males and bears on food

The Maine Department of Inland Fisheries and Wildlife species page calls the bear season framework fairly constant back to 1990. The fall season "opens the last Monday in August and closes the last Saturday in November."

With beechnuts scarce, most of Schooley's northern females were denning over mid to late October. That period ends before the late November close. When nuts were abundant those females remained active into mid to late November, so the Saturday close sits in their entrance period. The finding covers most females in those northern areas. It does not assign odds to one hunter.

Ternent listed statewide seasons of 15 to 24 November 2010, 14 to 23 November 2011 and 12 to 21 November 2012. Ahead of those seasons, 4 of 11 adult females had denned. The juvenile male mean was still 31 December. A late suburban hunt in that sample sought bears that had not quit. Males and juveniles made up most of the bears still out. Adult females remained outside as well when their entrance dates were still ahead.

Our Pennsylvania season paper tallies how 2024 harvest fell across season segments. Some units include December dates and the tally does not give sex. Open it for the check-station calendar. Read the collar work here for the classes dens had started to take.

Our Virginia acorn paper shows that poor-mast years once gave archery a larger share of reported bear harvest. The state plan offered extra movement plus later denning as one possible reason. This page holds the timing evidence that paper lacks. A harvest share is not your chance to kill a bear.

Our Minnesota 2025 paper records a rangewide fall food index higher for 2025 than for 2024. The index surveys nuts and shrubs and it does not date den entry. On a Minnesota hunt, use the index as a reason to check oaks and hazel you can reach.

Our rule starts in mid-October with one feeding patch revisited each week. Note whether fresh shells, scat or tracks remain. Sign that holds means the patch is still being used. If sign fades after the nuts drop, check the next patch that still has mast before you call the season done. If the next patch is quiet as well, our read says the bears needing that food have begun denning. First to leave are pregnant females and any with dependent cubs. Look into December for males and juveniles where those studies still had them moving. Season dates differ across states and units. Confirm the dates with your state agency before a hunt.