Do have rabbits as a pets, do you just love cute little animals and you are curious to know how they stay warm in winter? Well, you are definitely in the right place and I have got some really juicy and fascinating facts for you.
Rabbits are small, unique, and interesting mammals ( having an average weight and length of about 4.2 – 4.7kg and 20–50cm respectively) with short fluffy tails, characteristic long ears (that can grow up to 10cm), and vibrissae ( whiskers). According to the Guinness World Records, the world’s longest rabbit is a Flemish Giant about 4 feet 3 inches ( 129cm) and 49 pounds (22kg).
Various Measures Rabbits Employ To Keep Warm In Low And Freezing Temperatures
To maintain a warm body temperature(homeothermy) rabbits need to conserve heat. Heat is lost to the environment by the skin when the temperature of the environment is lower than the body temperature. If a body’s surface area is large when compared to overall body size, a greater percentage of body heat will be lost.
Conserve Heat Through Their fur
Rabbits are small animals therefore they have large surface areas relative to body size and as a result, would lose a greater percentage of body heat than larger animals would. However, the fur of rabbits traps dead air next to their body surface and this creates an insulating effect.
Also, this air trapped within and between their bod provides thermal insulation for the animal. They achieve this through their ability to make the hairs on their skin stand up. This action is enabled by the tiny muscles, known as erector muscles, attached to their hair follicles. This is an adaptation that helps rabbits reduce heat loss from their body surface.
Consequently, during winter most rabbits develop a winter coat(thick coat of fur), and their fur coat becomes denser. Usually, wild rabbits grow denser fur coats than domestic ones. Rabbits also tend to have coats of lighter colors during this period.
The thermoregulation system in rabbits helps them retain body heat in low-temperature conditions. As we have seen, their fur is very critical in thermoregulation. Thermoregulation is the process that an organism uses to maintain optimum temperature relatively independent of external temperature conditions.
The auricles(pinnae)of rabbits are another very important organ in thermoregulation. Their ears are long and have a large surface area, in cold weather, the ears of a rabbit are folded; to enable reduced exposure to the surrounding temperature. The blood vessels in its highly vascularized ears are constricted; this limits blood flow through the ears hence maintaining optimum body temperature.
To a great extent, the heat generated by the rabbit is mainly gotten by keeping it’s body’s metabolic rate high. The metabolic rate is the speed at which chemical reactions occur in body cells. A high metabolic rate means a faster rate of these chemical reactions resulting in increased production of heat.
Experiments have shown that mitochondria (the cells’ powerhouse) in the body cells are more abundant in Mammals than other animals. The additional mitochondria sufficient energy to keep the metabolic rate in rabbits high. When rabbits are cold they can also generate little spurts of energy by shivering. This occurs when many muscles contract almost simultaneously thereby introducing small amounts of heat.
Food With High Fiber Content
Considering the above, it is clear that during winter months rabbits need an increased food supply; an intake high enough to make up for the extra calories spent due to increased metabolic processes. It is also important to note that rabbits need adequate food to enable them to build up a layer of insulating fat because by burning the fat in their brown adipose tissues heat is generated.
Rabbits are warm-blooded so they require a lot of energy to maintain homothermic . Therefore, they require much more food supply than poikilothermic (cold-blooded) animals of similar size. The energy they require is mostly gotten from what they feed on. Food when digested provides chemical energy in the form of Adenosine Triphosphate (ATP; the only form of energy a cell can utilize).
Also, rabbits eat food materials with high fiber content and the digestion of fiber in the caecum produces considerable heat. Also, feeding on long-stem grass hay helps increase the heat generated by fermentation processes. All these help keep rabbits warm.
Furthermore, they stay in insulated areas during winter and usually go in search of food at dawn or dusk when the temperature of the surroundings is more favorable. Due to the nature of the vegetation during the winter months, they feed on mostly wood-based food sources such as twigs, tree barks, bush buds, etc, as well as woody plants.
They make burrows in places like thick bushes, under thick vegetation, in evergreen trees, hollowed-out stumps, brush piles, and so on.
It is worthy of importance to note that the circulatory system of a rabbit plays a very vital role in homeothermy (maintenance of body temperature). Blood produces very little heat, however, the blood absorbs and distributes heat to all parts of the animal’s body.
Also, when their body temperature gets low, tiny blood vessels near the surface of the skin(capillaries) constrict, this constriction is termed vaso-dilation. This causes decreased blood flow to the skin and consequently less heat is lost in the form of radiation.
Rabbits are not to be confused with the hare which belongs to the same family, Leporidae as the rabbit. Hares have longer ears with markings, and longer hind limbs, lead more solitary lives; live in pairs or singly, make their nests above ground( whereas rabbits make burrows underground), and are generally bigger than rabbits.
Thus, the scientific classification of the rabbit is:
Kingdom — Animalia
Phylum — Chordata
Class — Mammalia
Order — Lagomorpha
Family — Leporidae
Genera — About 8 including Oryctolagus, Poelagus, Remerolagus, Pentalagus, Bunolagus, Brachylagus, Nesolagus, Sylvilagus.
Specie — There are more than 50 species of rabbits. The domesticated ones(European rabbits) are Oryctolagus Cuniculus.
Nevertheless, rabbits and hares are both unique for their long sensitive ears, strong hindlimbs, and sweeping eyesight(each eyeball can make a 360° rotation), all these evolutionary adaptations keep them awake to danger and help them evade their predators.
Some rabbits live in the wild while others are domesticated. Rabbits being Mammals have warm-blooded metabolism, generally, mammals are endomorphs; they use metabolic processes to maintain constant body temperature.
That is why they are referred to as warm-blooded because they regulate and maintain a relatively high and constant internal body temperature independent of the surrounding temperature. That is to say, they keep warm despite the temperature of their immediate surroundings.
Isn’t nature simply amazing? It provides living things with necessary structural, physiological, and behavioral adaptations that’ll promote their survival despite certain unfavorable factors or conditions.
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