How do wildlife celebrate the New Years? Well, it goes something like this….10, 9, 8, 7, 6, 5, 4, 3, 2, 1, zzzzzzz. Yes, that’s right – they’re sleeping!
When it comes to the New Year, we humans have a rather strange way of celebrating. We go out in the freezing cold, party horns in one hand and libations in the other, to wait for a huge ball to drop out of the sky and announce midnight with a big bang and fireworks; meanwhile, the rest of the natural world is hiding away inside cozy dens hibernating and waiting for a more sensible time to celebrate – spring!
In this, the second of our winter wildlife series, we will be exploring the wonders of hibernation. Take our quiz and countdown to becoming a hibernation expert.
So close, try one more time.
#1 Which of the following are not “true” hibernators?
NPS Photo / Kevyn Jalone
Even though bears are the classic icon of hibernation, there is some debate as to whether they are true hibernators because their version of hibernation has some key differences from other mammal hibernators. While bears do show the classic signs of hibernation, including a slowed breath, heart rate, and metabolic rate and a lowered body temperature, their state of hibernation is not as extreme as other hibernators. For example, a hibernating bear’s body temperature is only about 10 degrees lower than normal, while most hibernating mammals have body temperatures close to freezing. Since they don’t have to warm up from such cold temperatures, they can also wake up more quickly. This makes them better adapted to react to danger (winter hikers beware).
#2 During hibernation, a little brown bat’s (Myotis lucifugus) heart rate drops to how many beats per minute?
Hibernating Indiana bats (Myotis sodalis) credit USFWS/Ann Froschauer
As Tricia Dutcher, former educator for the Nevada Department of Wildlife, says, “Bats turn into ‘batsicles.’” While hanging upside down and hibernating, their heart rate goes as low as just 5 beats per minute, which is a big contrast to the 1000 beats per minute that they sport during flight.
#3 Hibernating animals don’t eat or drink.
Most mammalian hibernators slowly elevate their body temperature and wake up at certain intervals during hibernation so that they can move around, eat and use the bathroom (a special separate room in their den). Here’s another classic example of how bears differ from “true” hibernators. Once they’re hibernating, bears don’t eat, drink, defecate or urinate.
#4 Do hibernating animals have dreams?
Bon Elsdale/The Image Bank/Getty Images
Hibernating animals do not reach the REM (rapid eye movement) stage of sleep when dreams occur.
#5 Which of the following animal hibernates in large groups, sometimes numbering up to 1,000?
Diamondback Rattlesnake/NPS Photo
Frightening as it may seem, rattlesnakes do tend to congregate in communal dens when the weather gets cold, and their numbers can reach 1,000 per den. And when it comes to winter roommates, they aren’t super picky. They’ve been known to share their dens with other snakes, turtles, and small mammals. We should also note that reptilian hibernation is technically called brumation.
#6 What is the only bird that hibernates?
The common poorwill (Phalaenoptilus nuttallii) is native to Nevada and the Southwestern United States and Mexico. Although, it does migrate to warmer areas during the winter, it is also able to enter a state of torpor, with a lowered body temperature, heart rate, and breathing for days or weeks at a time. This adaptation helps the poorwill survive the winter months when their main food source, insects, are not very abundant.
#7 Which animal can stop breathing during hibernation and still survive?
A wood frog (Rana sylvatica) in Rocky Mountain National Park/ NPS Photo
Meet the true living dead! Frogs are specially adapted to cold conditions and some can literally freeze and then come back to life. In most cases terrestrial frogs seek out warm places where they can hide out for the winter, usually by digging down below the frost line. But in the case of the wood frog (Rana sylvatica), it’s not such a great digger and may end up in a situation where it will freeze. It accumulates a high concentration of glucose in its vital organs to keep them from freezing, while ice crystals form in other parts of their body, like under the skin and in the bladder. They will even stop breathing! For all intensive purposes, they appear to be dead, but when things warm up, they come back to life and keep on hopping.
#8 Which type of queen bee hibernates in the winter?
First off, who knew there were so many types of bees? Carpenter and leafcutter bees do hibernate, but it is their larvae that hunker down for the winter – not the queens, and honey bees remain active all winter long. So that leaves the bumble bee as the correct bee with a hibernating queen. In the spring she will emerge from her winter home (usually a hole in the ground or stream bank) and start a nest, where she will lay eggs and start a new colony. At the end of the summer, the original queen and all her worker bees will die, but only after a new queen has mated and left the colony to go off and hibernate and start the whole cycle again the following year.
#9 Which of the following insects can produce an internal antifreeze?
Photo by IronChris: https://commons.wikimedia.org/wiki/File:IC_Pyrrharctia_isabella_caterpillar.JPG
Woolly bear caterpillars are the larval form of the Isabella Tiger Moth (Pyrrharctia isabella). They spend the winter months hanging out in leaf litter in a dormant state called quiescence. The leaves act as an insulating blanket keeping them warm, but sometimes temperatures drop below freezing and the blanket isn’t quite sufficient. To deal with this situation, woolly bear caterpillars produce a cryoprotectant that keeps their hemolymph (insect blood) from freezing.
#10 Which of the following common pets hibernates?
Photo by Pogrebnoj-Alexandroff https://commons.wikimedia.org/wiki/File:Butterfly_Goldfish_02.JPG
Gulp! Better think twice before you flush that lethargic goldfish.
When water temperatures get cold, goldfish go into a dormant state where they slow down, quit eating, and hang out at the bottom of the pond/lake. Even when there’s ice on the top of the water, the bottom of the pond will still stay warm enough for the goldfish to survive. This is because water is most dense at 40 degrees Fahrenheit and the denser water sinks to the bottom of the pond.