Rob Rich

So definitely not hairy. It is more scaly. So the beaver tail is really a fascinating part of their body in a lot of ways.

For one, it's used a little bit as a rudder as they're swimming through the water. And so it can help them steer a little bit. It's also important when they're propping up to chew down a tree or whatnot. And one of the most important functions of it, though, It's a very important alarm system as well.

You've probably either heard yourself or heard of beavers slapping their tail as they get alarmed by predator or potential threat or some other non-related beaver or some other concern in their environment. They will really have this impressive slap.

action on the water, and it is kind of jolting, and that is a warning to other beavers that there might be a threat around, and so they know how to respond to that. But the fourth one that's so important that the tail does is that it's very much a heat or a thermoregulation and heat storage, energy storage organ.

In the winter, that is the part of their body that becomes quite larger than it is in the summer. They have a lot of body fat, but they take on most of that in the winter and store it in their tail.

And so that is really important for one of the ways for them to keep warm in the winter. So the outside is very scaly, always black. And that has also been shown to have a unique signature. You can look at the tail. and tell individual beavers by their tail details, just like we can with a fingerprint on a human.

But then inside of the tail, it's just very thickly layered of white gelatinous kind of fat. And so all that fat is what's really important to further heat storage in the winter.

There is a central node of vertebra extending down through the tail that is in the center of it there, but it's more filled with more capillary like blood vessels. And so there's very lot of blood exchange in there that keeps it from freezing in those times. And again, serving that heat storage purpose. So other than that central area of bone going down the middle, it is entirely fat pretty much.

Sure.

Their teeth are supported by a skull that makes their teeth effective. And so they have a very flat-topped, wide skull with these things we call zygomatic arches, which are what we call cheekbones sometimes.

And so when those are so wide spreading, that allows for a lot of muscle attachment coming down over the top of their cranium, attaching to the outside of those cheekbones, and then going down into their mandible. And so... All that complex muscle attachment does make for a lot of jaw strength.

I can guarantee you it's quite strong to bring down to cottonwood or a large tree that is double the size of their body or something.

But the teeth themselves, like all rodents, they're defined by, you know, ever-growing incisors. And so those are kind of the hallmark front teeth that we see. And then they've got a really robust set of molars as well. And so... The molars are for grinding, masticating all that wood pulp down is important. But the incisors are what do the heavy work of the cutting.

And so on the top ones, they're very orange on the outside. And so if you see a beaver's front teeth, you will see that orange that's enamel. And it's colored that way because of some of the iron and the compounds that they eat in the wood that they're having. But that closes over a wider area on the bottom teeth that is called dentine. And so that wider area is softer. The enamel is harder.

When they rub against each other like that, it's a constantly sharpening chisel. And so the beaver's teeth are extremely sharp and constantly becoming more so. And if they don't have access to wood and don't keep gnawing and working on that, then The teeth will keep growing and can become quite a dental hazard for them. So they do require wood for that purpose as well.

But yeah, hard enamel outside, soft white kind of dentine on the inside for those incisors, and then just a lot of continuous action to keep it sharp.

Great. So they are definitely 100% vegan. No animal fare of note in maybe an insect or something will slip in occasionally, but there's very minimal to no record of of them relying on any animal food in their diet.

And so in the spring and summer and warmer months when the veg is succulent and there's a lot of herbaceous or non-woody plants out there, there's a number of wetland-associated plants that they will eat. They will also use the roots of certain things, like water lily roots are sometimes important for beavers.

And just in the water lily pad leaves, a lot of those succulent plants are not available, certainly year-round. When they cut down a tree or cut down a branch or whatnot, they're not ingesting the entire thing. They're mostly after what we call the cambium, which is this thin layer of sugary cells where the tree is actively growing. And so most of what we call on a tree is actually dead cambium.

cellulose material. It's not something that is nutritious in any way, but they will seek out that cambium layer just below the bark and below before you get into the real kind of deadwood of the tree. And so they will eat first and then use some for building or some they're just used for feeding as well. A little bit of a mixed bag there.