Are Beavers Nocturnal? Here’s the Answer, and the Reasons


We all like to see beavers at work in their natural habitat, but truth be told wildlife photographers find it harder to get daylight footage of Beavers as opposed to nighttime footage. So one would assume they’re Nocturnal. Or are they? Here we’re going to dive into whether Beavers are Nocturnal, or whether they’re found to be active at other times – and why.

Are Beavers Nocturnal? Beavers are primarily nocturnal. Being active for about 12 hours each night, building and maintaining their habitat and foraging. Beavers forage mostly during bright moonlight. However, since they stay active from late evening till early morning, beavers could be considered Crepuscular or even Diurnal.

There are several misunderstood notions regarding whether beavers are nocturnal naturally, or if they’ve adapted to this more nocturnal behavior because of different underlying historical reasons. With that question in mind, let’s get into some details. 

active beaver
active beaver in daylight

Is a beaver nocturnal or diurnal?

Beavers are largely considered to be nocturnal. There are rare instances where you might come across a beaver actively roaming during the day, meaning they do have Diurnal tendencies.

Almost all of their daily chores, from foraging to building habitats and maintaining them are done during the night. Specifically, they tend to forage more during the bright moonlight which would suggest they are Nocturnal.

But, there are plenty of arguments that say beavers are not naturally meant to be nocturnal.

Their foraging habit or behavior is a valid point for this argument. Many believe Beavers are seen foraging for food at twilight hours because their eyes are naturally no longer adapted to see well in the dark. 

This brings us to the other point that beavers may naturally be a diurnal animal (daylight activity) and that they’ve adapted themselves to be nocturnal.

You might think that’snot possible, but evolution can change animals dramatically. So let’s fill in some details for you and provide the argument.

Beavers could be diurnal or crepuscular

To prove this, a BBC study states that we need to go back to the legacy of a long period of persecution of Beavers that began in the Pleistocene epoch (2.6 million – 11.7 thousand years ago). 

The study says that during this period, human hunters would take up their hand-held weapons and go hunting during the day time. This was a period long before the introduction of animal traps. 

At that time, of course, humans were still Diurnal, and so they only option hunters had was whatever they could hunt in the daylight hours. It’s during this time that the ancestors of beavers were heavily hunted, especially because of their large size 27.5in – 40 inches. (70-100 cm) almost the size of a small dog.

They were hunted for their many benefits, ranging from an important source of food, dense warm, waterproof fur, and castoreum which is a specific substance from their castor glands that was used in medicines and perfumes.

This heavy hunting era wiped out many species of beaver – in many regions.

The study also suggested that because of this heavy hunting during the daytime, the beaver’s activity pattern was gradually adapted to nocturnal and even crepuscular active periods.

As of now, even if they’re not hunted anymore, their behavior i.e. becoming active at night – continues or remains the same. More like an adaptation to a predator-free environment, that’s inherited by the ancient species and passed down through the ages to the current species. 

In other words, this is where the nocturnal tendency developed by beavers to keep safe from predators continues – as a result of past experiences.

This adaptation pattern or phenomenon is referred to as “The ghost of predators past”. This is where a species continues its anti-predator behavior or activity even after the threat has been eliminated or disappeared completely.

Beaver Activity Periods
Beaver Activity Periods

The above chart gives you a visual indication of when beavers are more likely to be active.

A similar incident or phenomenon can be seen in pronghorns. Pronghorns are the second fastest animal on earth with only the cheetah clocking faster speeds.

A similar study has stated that Pronghorns had perfected their running prowess well over 10,000 years ago. Many believe it’s this same phenomenon that makes beavers nocturnal. 

While not everyone might accept this as being correct, the next part may support why this activity habit change may be true. 

Is a nocturnal behavior best for beavers?

The above studies stated that a nocturnal lifestyle or night-time activity may not, in fact, be optimal for beavers. This has been backed up by three main surprising findings.

  1. Firstly their eyes are not particularly adapted to see in the dark. This is one of the main reasons why they go foraging under the bright moonlight. There is also evidence that these mammals also tend to respond quicker under the bright moonlight.
  2. Beavers would lose less energy for thermoregulation (which is beneficial) if they remain active during the day – which is obviously warmer than at night. So it makes less sense for a beaver to be particularly active during the night and lose more precious energy.
  3. Most importantly beavers are herbivores, so their food is always present anywhere outside anyway during the day. They do not have any reason to forage for food during the night as there is nothing to hunt or prey on that is active during that time, neither do they possess sharp eyesight at night to do so. 

What do beavers do at night

At night Beavers have plenty to keep them busy, even though their eyes aren’t that good at seeing during the night, they tend to like to do the work under cover of darkness. A full moon is a night when a Beaver can accomplish the most.

Dams across rivers

Much of the time Beavers are busy tending their habitat, they gather up all kinds of natural materials like mud, branches and twigs and even hole logs made from sections of trees which they chopped down themselves.

They then use these materials to begin blocking up the main river and stream routes. These blockages cause overflowing and pond or lake type areas. Where the dams break the Beaver will repair them. It is in these Ponds like environment that the Beaver will make its home.  

Building lodges

Some beavers live in stream and river banks and are reinforced with materials the same as used on the dams, mainly mud and sticks. But most beavers live in Lodges. These lodges are created after dams have been built and areas are flooded, the dams are partially submerged with elaborate tunnel runs that connect various caverns and dry sleeping areas, and usually have more than one entrance

Foraging for food

Beavers enjoy eating plants and flora that grow in and around their waterway domains such as water lilies, grasses, leaves, nuts, and clovers. When the sun is waning and the dusk falls, the beavers will usually emerge to begin feeding.

Beavers are known for their gnawing on trees, they tend to strip the bark and eat the green fresh bark underneath, as well as stripping branches and leaves too. Often they’ll use the remainder of the tree as part of their dam activities.

Preparing for winter

During the fall a beaver will be most active as they make preparations around their habitat for winter setting in. They do not hibernate as such, but activity is reduced and as they know food sources will be scarce they do stockpile a certain amount of food to last them over the winter months.

These stockpiles of branches, twigs, and bark will be pinned down with rocks and mud somewhere near to the underside of their lodge, with a subterranean access point so even when the water is frozen over they’ll be able to access their store of food. It will remain there until they need it.

Seasonal activities

Spring is a time for mating and relaxing as an abundance of food means there is plenty to keep them going right the way through summer with only light habitat duties required and focus is also on rearing their offspring.

As the Summer turns to fall they become super active, ensuring all their dams are secured and in place ready for the winter. It’s during fall that you’re most likely to see a beaver out during twilight or even at dawn, so be sure to head out, look for signs of beaver activity, sit quietly and wait for them to appear.

As Winter sets in, the activity will be reduced, but they don’t hibernate. Instead, they will take it slow, holed up in their wam lodges, using up their stockpile of foods and waiting out the winter.

Resources

Continue the fascinating story of beavers in North America, including their history, near extinction, and current comeback and what scientists think of them now.

Leave it to Beavers (DVD)

To conclude

So currently, despite some infringements on daylight hours, we class beavers as being nocturnal, occasionally crossing into diurnal as their activities during the day are mostly around Twilight times and only more so at specific “busy” times of the year.

Is it likely that beavers will ever become active during only daylight hours again? Well unless evolution provides a reason to return to daylight times then that’s probably not likely.

We’d love to hear your comments below, but if you need some further reading or classroom resources then here are some things that will help.

More about Beavers

Michael

A Certified Ecologist and an Entomologist, Michael has been interested in all aspects of Nature for many years. It's only now he's decided, along with his partner Fran, to begin documenting what he knows.

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