Groundhog Observations 2003-2017
By Susan & Joseph Sam
WE believe groundhog behavior has been misinterpreted and misunderstood due to lack of observation time of groundhog families and lack of equipment to maximize observations. With the addition of trail cameras in 2016, we are proving what we have believed to be true from past observations.
IT has been thought that the father does not assist in caring for the young because he is not needed. It’s been thought he was not even tolerated and never allowed to enter the nursery. We disagree, in part. The nest chamber has been documented by W.J. Schoonmaker to be about sixteen inches wide and fourteen inches high  While this nest accommodates an adult male and female, it would unlikely be large enough to accommodate two adults as well as babies. While the male may not actually enter the burrow after birth of babies, he has been documented at each opening of that burrow. He has also been documented marking objects and leaving his scent in the barn near, and surrounding, the natal burrow.
WE have been saying for years that the male groundhog does not sever ties to his mate when babies are born. We have shown presence of the male in both video and photographs after birth of babies. With addition of trail cameras, we are able to actually confirm his presence inside the barn where the natal burrow is located. We have also documented 5 different males interacting with juveniles; George, Luke, Raggedy, Fred, and Reggie.
IT has been thought the female drives the male from the den when she is near to giving birth, or has given birth. We have found that once the female has given birth, the role of the male changes. In addition to visits to his mate, he makes rounds to other burrows which will be used for training of the babies after they emerge from the natal burrow. He also assists in burrow maintenance.
IT has been thought that groundhogs have a winter den and a summer den. On our property, they have multiple summer dens. The “winter” den is used for hibernating, mating, birth of young. It is a home base and used continually. The “summer” burrows are used in training and raising of the young as well as for escape from predators.
AS we have observed the same female and male mated in more than one year (Wilhelmina & Gregory, Wilhelmina & Woodrow), it is possible that groundhogs mate for life…assuming the survival of each. At least one researcher has stated the female may have more than one mate in a year and we agree this is possible. Since we have confirmed Raggedy is a male, it is possible that he and Luke were both mates of Heidi in 2015. Raggedy was her mate in 2016, and probably again in 2017.
WE believe there are a number of groundhog actions that have been misinterpreted and misunderstood. Mounting behavior is one example. While this is seen in mating, we have also seen it in play between juveniles and also between adults and juveniles. We call this “overlapping behavior”, actions that are used in multiple circumstances.
CHASING is another example. We have seen various chases, some with mother chasing young, mate chases, and chases between other groundhogs. Chases are not necessarily a hostile aggressive act. They may be disciplinary, playful, or perhaps for training or exercise. On only few occasions have we observed a chase that was clearly meant to run off another chuck. Occasionally we have observed a groundhog briefly chase a rabbit or bird.
VARYING environments may necessitate adaptations in groundhog behavior, and individual behavior may differ somewhat. We do not believe, however, that the activities and behavior we have observed and documented is exclusive to our property.
WHILE more research is needed, our observations have convinced us that groundhogs are a family unit with mother, father, and offspring and they operate as a family unit. Loss of the mother while she is still nursing leaves the young without nutrition. Loss of a male in the family leaves the family more vulnerable to predators and animals that would take over their burrows. While the female may do the majority of training, increasing observations indicate a role here as well for the male. Most or all juveniles disperse in late July or early August. They have a lot to learn in a short time! Much like a baby boot camp.
 W.J. Schoonmaker, The World of the Woodchuck, page 105