In This and the next 2 articles, Rabbi Samuel Waldman will focus on the amazing beaver.
In many ways the Beaver does some amazing feats clearly not possible without Hashem being behind them, as we shall see. But to accomplish those feats their anatomy (their organs and limbs) has to have unique features, rarely, if ever, found in similar creatures. All put together by Hashem in this most uniquely structured animal.
Beavers are large brown furry rodents with small eyes, small rounded ears, large orange teeth, and a large flat, scaly tail. They weigh between 44 to 60 pounds. They are about 3-4 feet long. Beavers live in ponds, lakes, rivers, marshes, and streams all across North America.
Beavers have long, sharp teeth known as incisors that are used for gnawing and chewing and grinding. These teeth are always growing so it is important for the beavers to keep them trim by continuously gnawing on trees and branches. The incisors on beavers can grow as much as 4 feet per year! Beaver teeth are so strong that they are able to chew through large tree trunks. Beavers have tremendous cutting pressure with their teeth because of the unique shape of their skulls and the muscles attached to the jaw. These exert a powerful lever action, at least twice as powerful as the jaw strength of humans. The front surface has very hard enamel that wears down slowly. The backs are of a softer material that wears down a little faster. This somewhat unequal wear and tear gives the teeth a chisel-like edge, great for cutting the bark, and beneath the bark, of trees. The sixteen molars (back teeth) used to grind the beaver’s woody food seldom show any sign of wear. The molars are uniquely shaped to be able to grind the wood into digestible fibers.
Beavers mostly love to eat the bark, and right beneath the bark, and the leaves from the trees that they help knock down by chewing through the tree trunk. At times they’ll also eat plants, grasses, and some aquatic plants as well. However, they don’t eat the actual wood of the trees. With the leftover wood under the bark they build their dams and lodges. (We will talk about this in the next article.) Although they are found in or around water much of the time, they do NOT eat fish. They usually prefer trees between 2-6 inches wide in diameter. A busy beaver can chew through a 5-inch willow tree in 3 minutes! A pair of beavers takes down about 400 trees per year!
The beaver has several special waterproofing devices that go into operation right when it submerges under water. Special valves in the ears and nostrils can be snapped shut to keep out the water. Even though we humans also swim, but we don’t stay underwater for too long. Beavers typically stay under water 3-4 minutes straight and when fleeing from predators they can stay under water for as much as 15 minutes straight therefore they need these extra protection valves! (more about how they can breathe underwater for so long in the last article) They also have special see-through eyelid membranes (called nictitating membranes which is like a third eyelid) that slide over the eyes like goggles to protect their eyes from all the dirt in the water, and it helps their underwater vision. Very few mammals have this special eye protection. (Most birds have this protection, but not mammals.)
They are also able to gnaw and chew underwater without swallowing and chocking on the water because of the specialized design of their mouths. Behind the incisors, their furred lips form a loose flap that is able to close shut behind these teeth, leaving them exposed for use but stopping water from entering the mouth. Another unique breathing feature is the passage from their nose to their throat. This important airway connects directly to the upper lungs, permitting the beaver to chew and swallow, and breath through its nose at the same time. We can’t do that. When we swallow, we can’t breathe at the same time that we swallow.
They also have a very unique digestive system. Although many other kinds of animals can digest the cellulose found in plants, beavers are more dependent on it than most other animals. Beavers are able to digest about 30 to 35 percent of the cellulose contained in the woody material they ingest, (which is a very high percentage) partly because of special digestive secretions in their stomach and partly because of colonies of special digestive bacteria that are found in their gut. They also have an especially long and extended lower digestive system that is thereby able to handle the woody material that passes through it.
The front and back feet of the beaver have 5 digits/fingers which enables then to hold on strongly to branches and other material. The back feet are webbed. They are from the very few mammals that have webbed feet. This enables them to swim much faster and with much more power per movement of their feet.
A unique “feature” that is found on the first two digits of their rear feet is a unique double claw, sometimes called a split nail. Here, a thin second nail lies closely next to a larger main nail, creating a narrow slit. Beavers are able to move these double claws like a clamp and this feature has at least one important function—it gives the beaver added efficiency when combing and grooming its fur. This action also helps spread oil over the fur, which is crucial for helping repel water from their fur.
The two sets of double nails differ slightly in construction. The inner nail is larger and rougher along the edge, forming what beaver experts call a “coarse comb.” The outer nail is smaller and has a finer, minutely serrated edge. This nail is called a “fine comb.” Each has their function in taking care of the grooming needs of the beaver.
Beavers are known for their thick, heavy fur which encases the beaver and it gives it a remarkable advantage in its watery environment. This warm outer blanket also helps it survive in extremely cold weather. Beneath the fur is a thick layer of fat that is crucial for keeping them warm in the winter.
Like many heavily furred mammals, beaver fur consists of two coats. An inner, or undercoat, consists of extremely fine, soft hairs that form a dense pile over the entire body, except for the feet and most of the tail.
Growing through the underfur are longer guard hairs that extend up and beyond the inner layer. In adult beavers, guard hairs are typically about two and one half
inches in length and these hairs are much thicker and coarser than the hairs found in the undercoat.
Beaver’s guard hairs are normally shiny, a condition enhanced by their spreading of their oil onto their fur. The oil is produced in their oil glands. This is not the same fluid that is produced in their castor glands (which have a special unique scent unique to each family, and it’s used as a marker to show that this is their family’s territory). Both sets of glands are found close together under their tail. Because of the oil spread onto the fur, their hair has a slick, smooth feel to it, just the right texture for gliding through a wet environment. If not for their water repellent oil, the waterlogged heavy fur would be a huge drag on their swimming capabilities, so it’s essential for the beaver’s functionality.
Finally, we will discuss its completely unique tail. It is wide and flat and it is basically hairless, and it has a layer of dark, tough skin.
No other creature has anything like it (with the exception of the platypus). The tail is used for a few important functions. Firstly, it acts as a rudder helping it steer the beaver while in water. The tissue in the tail is a fatty substance that is important to the beaver as a source of stored energy in times of food shortage. The densely, concentrated network of blood vessels in the tail also helps the beaver control its body temperature, radiating excess heat when it is too warm and limiting heat loss when the outside temperature is too cold.
On land, the tail forms a sturdy base, creating a stable tripod in conjunction with the two hind legs when beavers are standing up to gnaw on trees, a common activity. Beavers also rely on their tails to create loud slaps on the surface of the water, the standard beaver alarm when sensing danger.
Now, if you were paying attention, you would have noticed that just about every part of the beaver is SPECIAL, it’s unique. How can an accident put together so many uniquely, special parts of this amazing beaver? Review the article and you will see how every step of the way there’s tremendous uniqueness to this animal.
We will see in the next article what amazing things this unique beaver is able to construct with its unique body structure that Hashem gave it.
