Moose (Alces alces) are the least social members of the deer family in North America. They are often described as “solitary”, except for groups associated with reproduction: mothers with calves, and gatherings during the rut. However, moose sometimes form other types of groups. Certain conditions favor social interaction, and they are more often met in the northern portions of its range. So, moose are generally more social in Alaska and Canada, and less social at the southern fringes of its range, such as southern New England. But, as camera traps constantly remind us, animals do not read scientific publications, and the Massachusetts moose I’ve captured on video over the past year sometimes do appear in small groups. Here I’ll discuss why certain conditions may lead to increased social interaction in moose, and then share some videos of unexpected moose associations.

First, a word about the title. “Moose Associations” is a nerdy reference to the term “loose associations” which refers to odd connections between ideas, as seen in people with certain mental illnesses. (My former career was in psychiatry.) Communicating with someone whose thinking is “loose” can be challenging because they are hard to follow, yet their train of thought makes sense to them. Like loose associations, certain moose associations don’t seem to make sense to us, yet to the moose, they are undoubtedly sensible and meaningful. We just need to make more of an effort to understand them.

Conditions that Favor Social Interaction

Open Landscapes

As relatively solitary creatures, moose actively avoid each other, and may become aggressive during close encounters. They are sometimes described as having an aggressive or ornery disposition, which may come as a surprise to human observers who see them as placid and tolerant. That’s because they often are placid and tolerant around humans (though they are unpredictable and can be dangerous to people). Their aggressive inclination becomes evident when moose are in each other’s company. Yet, in open landscapes, such as shrub communities and alpine tundra, moose do sometimes associate amicably.

Conventional wisdom says that grouping in open areas is a defense against predators since more eyes mean more effective vigilance, which is helpful where protective vegetative cover is lacking. This is undoubtedly true for herding animals, such as elk. But is it true for moose? Not necessarily. A study in Scandinavia found that moose grouping behavior was the same before and after recolonization by wolves. Wolves did not make moose more likely to form groups.

If protection from predators isn’t the cause of increased social interaction among moose in open areas, what is? Just throwing some ideas out — maybe moose tolerate close encounters better in open areas because they can see each other. Maybe the forage is better quality or more abundant in these habitats so that they don’t feel the need to space themselves out. If you have any other ideas, please feel free to explain in a comment.

Crusted Deep Snow

Long legs allow moose to move efficiently through snow of moderate depth, but movement through crusted, deep snow is labor intensive even for these towering cervids. So in such challenging conditions, moose may group up to form trampled “yards” and trails. It is often said that this relates to predation risk, since the much lighter wolves can glide over crusted snow, but maybe moose would create “yards” in such conditions even in the absence of wolves, simply because it saves them energy.

High Population Density

Habitat and snow conditions may account entirely for the increase in moose social interaction in the northern portion of their range, but it’s hard to ignore the fact that their population density is also higher in the North. Might grouping be more common partly because moose are more likely to encounter each other?

Videos of “Moose Associations”

Most of my camera trap captures of moose in Massachusetts have been of lone individuals (or mothers with calves), and I have always assumed it has to do with their more solitary nature, the low moose population density, and the prevalence of mature forest. Moose like young browse, which is less abundant in mature forest than in young forest, and that might force the animals to spread out.

Cow, Calf and Bull

In both northern and southern locales, a cow with a calf or two is least likely to associate with other moose. In a study comparing moose social behavior in Alaska, Montana, and Minnesota, almost no cows with calves associated with other moose outside of the rutting season. Alaska cows with calves were slightly more likely to associated with other moose, which isn’t surprising, given the much higher moose population density, more open landscape, and deeper snow in Alaska. Over 90% of cows with calves in Kenai, Alaska, and 100% of cows in Minnesota and Montana, avoided other moose outside the rut and post rutting period.

That’s why I was surprised to see the trio of cow, calf, and bull in February in the following video (Massachusetts). The snow was shallow and the mating season had long passed. Notice also in the video that the forest is relatively mature and the understory is sparse. It seems that moose would have every reason to spread out and no reason to group. I really don’t know why these three seem to hang out together, but I wonder if the bull is her son from the previous year, or perhaps one she mated with the previous fall.

When you view the video, keep an eye on the time stamp and the dewlap on each moose so you can appreciate that there are two different adults in addition to the calf, who are moving as a group.

Two Young Bulls

In June, two bulls appeared on two different cameras, a quarter of a mile apart, so they were clearly traveling together. Notice the appearance of a third bull, a larger one — he was never seen in videos with the others. The two young companions appeared to be moving along an extensive wetland system with large openings (where moose are more likely to group) and abundant aquatic vegetation (little need for competition). I’m wondering if they are twins who were recently forced out by their mother as she prepared to give birth this past spring.

Lone Bull

Now, just for the sheer beauty of this animal and his surroundings, here is a video of the lone bull in the same wetland as seen by a third camera. I hope he returns in the fall so we can see him in all his rutting glory.

Have you noticed moose forming groups outside of the rutting season? Please share your observations and approximate region in a comment below. I’d love to learn more about how they socialize in different areas.

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Sources

• Mansson, J., M. Prima, K. L. Nicholson, C. Wikenros and H. Sand. “Group or Ungroup – Moose Behavioral Response to Recolonization of Wolves.” Frontiers in Zoology. 14 (2017).
• Peek, J. A., R. E. LeResche and D. R, Stevens. “Dynamics of Moose Aggregations in Alaska, Minnesota, and Montana.” Journal of Mammalogy. 55(1974): 126-137.