Brumation is a physiological state in reptiles and amphibians in the cold winter months that involves a slowing of metabolic processes, reduced activity, and minimal food intake. While often compared to hibernation in mammals, it’s not the same thing.
Examples of Animals That Brumate
Many reptile and amphibian species brumate, especially those living in temperate climates with harsh winters. Common examples include:
- Snakes, such as garter snakes and rattlesnakes
- Lizards, like bearded dragons and blue-tongued skinks
- Tortoises and some species of turtles
- Amphibians, including certain types of frogs and salamanders
Brumation vs. Hibernation and Torpor
While brumation is similar to hibernation and torpor, there are key differences:
- Hibernation occurs in mammals and involves a deep, prolonged state of sleep.
- Torpor is a short-term state of decreased physiological activity, seen in both mammals and birds, often lasting for just a day or night. Fish experience a similar state, but it’s longer-lasting over the winter months rather than short-term daily cycles.
Brumation occurs in cold-blooded or ectothermic vertebrates, while hibernation occurs in warm-blooded or endothermic animals.
Similarities between hibernation and brumation include:
- Changing day length and temperatures stimulate both hibernation and brumation.
- Animals feed heavily and build up fat reserves before hibernation or brumation.
- Animals stop eating during hibernation or brumation.
- Breathing, heart rate, and metabolism slow.
But, there are differences between hibernation and brumation, too:
- Brumating animals tolerate reduced oxygen levels, while hibernating animals need fresh air.
- In addition to fat stores, reptiles also build glycogen stores before brumation.
- Hibernating animals sleep deeply, while brumating animals experience waking and sleeping cycles.
- Ideally, most hibernating animals sleep all winter. Meanwhile, brumation involves periods of activity.
- Brumating animals don’t stop drinking water, while hibernating animals do not wake up to drink.
Why Brumation Occurs
Brumation is a survival mechanism triggered by decreasing temperatures and reduced daylight hours. As cold-blooded animals, reptiles and amphibians rely on external heat sources to regulate their body temperature and metabolic processes. Brumation helps these animals conserve energy, survive on limited food resources, and avoid the dangers of a cold environment.
The Brumation Process and Duration
- Feeding Increases: Many animals increase their food intake to build up fat reserves.
- Seeking Shelter: They start seeking and preparing suitable sheltered spots for brumation, such as burrow, under rocks, or in other protected areas.
- Gradual Slowdown: There’s a noticeable decrease in activity levels as the environment changes.
During brumation, the animal’s heart rate and breathing slow down and they enter a state of minimal activity. They may wake occasionally to drink water or bask in warm weather, but generally do not eat. Feeding a brumating animal harms it, since its metabolism is not high enough to digest the food. The food might spoil and cause illness.
The duration of brumation varies based on species and environmental conditions. It typically lasts from a few weeks to several months. Brumation usually ends as temperatures rise and daylight increases, signaling the arrival of spring.
- Increased Activity: Animals become more active, gradually returning to their regular routines.
- Feeding Resumes: There’s an increased focus on feeding to replenish lost energy reserves.
- Behavioral Changes: Some species display more aggressive or territorial behaviors, especially if the post-brumation period aligns with their breeding season.
Brumation Risks for Young Animals
Brumation is riskier for young animals, particularly for young reptiles. This increased risk is primarily due to their lesser energy reserves and ongoing development needs. Here’s why:
- Energy Reserves: Young reptiles often do not have the same fat and energy reserves as adults, so they might not have sufficient reserves to sustain them.
- Growth and Development: Young animals are in a crucial stage of growth and development. The slowed metabolic processes during brumation sometimes interferes with normal growth patterns.
- Immune Function: The immune system in younger animals is not as robust as in adults. The decreased physiological activity during brumation potentially lowers their immune responses, making them more susceptible to infections or illnesses.
In the wild, the timing of breeding cycles gives young animals the optimal chance of winter survival. For pet reptiles and amphibians, whether or not brumation occurs is a concern worth discussing with a veterinarian.
Role of Brumation in Reproduction
Brumation plays a significant role in the reproductive cycles of many reptiles and amphibians. Here’s how:
- Hormonal Changes: The physiological changes during brumation trigger hormonal responses that are crucial for initiating reproductive activities.
- Synchronization: Brumation helps synchronize mating behaviors. When multiple animals emerge from brumation at the same time, it increases the chances of successful mating encounters.
- Egg Development: Some species require brumation for the development of eggs or to stimulate ovulation after the animals emerge from brumation.
- Breeding Readiness: The post-brumation period often signals increased sexual activity and readiness for breeding.
Brumation in Pet Reptiles
Pet reptiles may not brumate as they do in the wild. However, some may exhibit brumation behaviors if their habitat mimics natural light and temperature cycles. Whether a pet reptile brumates depends on species, individual health, and environmental factors.
Not experiencing brumation usually is not harmful to pets, provided they are kept in a stable, appropriate environment. For some species, however, a period of brumation is beneficial, especially for breeding purposes.
Preparing a Pet for Brumation
If a pet owner decides to allow their reptile to brumate, or if the reptile shows signs of wanting to brumate, certain steps should be taken:
- Veterinary Check: Ensure the reptile is healthy enough for brumation.
- Adjust Environment: Gradually reduce temperature and lighting in the reptile’s habitat to mimic seasonal changes.
- Reduce Feeding: Slowly decrease the frequency of feeding before brumation. Stop feeding when brumation begins, as digestion during this period can be harmful.
- Ensure Hydration: Make sure the reptile has access to water.
- Monitor Regularly: Keep an eye on the reptile’s health and habitat conditions throughout the brumation period.
To prevent brumation, maintain a consistent, warm environment with steady light cycles. This can be especially important for sick or underweight reptiles for whom brumation could be risky.
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- Pet Talk (2021). “Turtle Brumation: The Benefits & Dangers of the Hibernation Cycle.” TAMU Vet Med. VMBS News.