Is climate change altering Arctic ground squirrels’ hibernation patterns?

Is climate change altering Arctic ground squirrels’ hibernation patterns?

Subject :Environment

Section: species in news

Context:

A new study (Science) analysed more than 25 years of climate and biological data. The findings include shorter hibernation periods and differences between male and female hibernation periods.

Details of the study:

• Arctic ground squirrels survive harsh Alaska winters by hibernating for over half the year.
• They still must spend energy to generate enough heat from stored fat to keep tissues from freezing.
• They resurface from their burrows more than three feet below the ground each spring, famished and eager to mate.
• The researchers found that females are changing when they end hibernation, emerging earlier every year, but males are not.
• Changes in females match earlier spring thaw.
• The advantage of this phenomenon is that they do not need to use as much stored fat during hibernation and can begin foraging for roots and shoots, berries and seeds sooner in the spring.
• Scientists think this could lead to healthier litters and higher survival rates.

Arctic ground squirrel:

• The Arctic ground squirrel is a species of ground squirrel native to the Arctic and Subarctic of North America and Asia.
• People in Alaska, particularly around the Aleutians, refer to them as “parka” squirrels, most likely because their pelt is good for the ruff on parkas and for clothing.
• Hibernation:
  • The Arctic ground squirrel hibernates over winter from early August to late April in adult females and from late September to early April for adult males, at which time it can reduce its body temperatures from 37 °C (99 °F) to as little as −3 °C (27 °F).
  • During hibernation, its core body temperature reaches temperatures down to −2.9 °C (26.8 °F) and its heart rate drops to about one beat per minute.
  • Peripheral, colonic, and blood temperatures become subzero.
  • The best theory as to why the squirrel’s blood doesn’t freeze is that the animal is able to cleanse their bodies of ice nucleators which are necessary for the development of ice crystals.
  • In the absence of ice nucleators, body fluids can remain liquid while in a supercooled state.
  • This process is being studied with the hope that the mechanism present in arctic ground squirrels may provide a path for better preservation of human organs for transplant.
  • The connections between brain cells also wither away in this state.
  • The damage should have resulted in death, but research on related species shows that these connections regrow after waking up.
  • In the warmer months, the squirrel is active during the day.
• Diet:
  • This squirrel feeds on grasses, sedges, mushrooms, bog rushes, bilberries, willows, roots, stalks, leaves, leaf buds, flowers, catkins, and seeds.
  • They will also eat insects, and occasionally they will even feed on carrion (such as mice, snowshoe hares and caribou).
• IUCN Red List: Least Concern.