HVS Member Tom L
“They’re Back and They’re Hungry”
Black bears are not considered to be true hibernators like many smaller mammals, but rather spend the winter in a less dormant condition known as “aestivation” Unlike the true hibernators, a black bear’s body temperature only drops several degrees while they are denned and their metabolism remains high. As a result they are capable of quick arousal if disturbed. During the aestivation period, they do not eat, drink, defecate or urinate, and they are capable of a quick arousal and wakening.
Considerable bear den research work was done with Catskill black bears in the 1970's and 80's by NYSDEC biologists. Research from the use of radio collars established that pregnant female bears typically enter the den before the males and usually begin doing so about November 20 in most years, followed by the sows with cubs a week or so later. Adult male bears and barren female bears stay out even longer and often don’t enter a den until mid December.
Most Catskill bear den sites occur in rock outcrops and cavities, although bears will also use hollow trees, brush piles and other natural cavities that offer shelter. Not all bears, especially younger animals, are adept at finding suitable dens, and in some instances bears have denned under porches of occupied houses, and in one case in a road culvert.
Pregnant females typically give birth to cubs in early January and newborn cubs come into the world weighing less than a pound. Litter sizes are typically single cubs or twins, although litter sizes of four can occur.
Den emergence by bears in the spring follows a reverse chronology. Adult males come out first, usually in early March, followed by females with yearling offspring in tow several weeks later. Lastly the females with newborn cubs emerge in early April; newborn cubs will weigh 4 to 5 pounds when they leave the den with the sow.
Black bears do not have a fidelity to a specific den site and will typically utilize a different location next winter. However, better den sites are often used by other bears, especially those sites that offer better den characteristics. In the world of bears, it’s first come, first served .
Upon emerging from the den, black bears not having had any food for several months will typically wander in search of food sources. Black bears are primarily vegetarians, and have been known to eat over 80 species of natural vegetation in NYS, however, most of the natural food sources are not present in April. Accordingly, they will seek out and take advantage of artificial, non-natural food sources that can include bird seed, garbage containers, compost piles, outside pet food dishes and a long list of other things that we leave laying around. Skunk cabbage is one of the first natural foods available in quantities and we’re fortunate to have early sprouting of skunk cabbage this spring.
Bears have excellent recall and will remember where they have found human food that they gain by pan-handling. Removal of the attractant is the simplest and only sure-fire method of insuring that a bear seeking food will not continue to visit your home. As more natural foods become available later in the spring, bears will rely less on scavenging foods from humans.
Still another interesting “bear event” that happens in the late spring is the dispersal of male yearlings. As the adult females approach the biannual breeding season, they usually will not tolerate the presence of their yearling male off-spring, and will physically (and sometimes quite violently) drive them away. As a result of having been driven off by their mother in late May and June, young male bears will wander aimlessly in search of new home range. Invariably, a number of yearling male bears will turn up in some pretty odd places. Many old-timers referred to the month of June as “the moon of the wandering bears” and as a result of their travels in search of a new home range, there is another spike in bear/human nuisance complaints. Yearling male bears are sexually mature and the refrain of the county-western song “Looking for Love in all the Wrong Places” comes to mind.
Black bear breeding reaches it’s peak in early July and the fertilized embryos float freely in the females uterus until later in the fall when they actually implant and begin development. All bears will go on a food binge in the fall, building up their fat reserves in preparation for the upcoming winter and denning period. Black bears have been documented to gain as much as two pounds a day during their fall period of gluttony.
And as food natural food supplies dwindle, bears will go full circle and once again avoid the harshness of winter by denning.
What goes around, comes around.