Chipmunks

Alex Re (00:00): Hello, welcome to On Wildlife. I'm your host Alex Re. On this podcast, we bring the wild to you. We take you on a journey into the life of a different animal every week, and I guarantee you, you're going to come out of here knowing more about your favorite animal than you did before this week. I'm talking about a forest creature that's tiny but has a big impact on its ecosystem. You've probably seen a few of them if you live in North America or Asia, but probably not for long because they're quick to run away if they sense danger. So join me as we head into the forest to talk about chipmunks.

(00:56): There are 25 total species of chipmunks and all 25 species are located in North America, with the exception of one which lives in Asia called the Siberian Chipmunk. Even though they're limited to North America and Asia, their ranges in those areas are pretty large. They can live as far north as Canada and as far south as Mexico. Chipmunks can live in a variety of different habitats depending on their species. Most species are either terrestrial, meaning that they spend their time on the ground or are Boreal spending most of their time in trees, but some species are actually a hybrid of the two. Chipmunks belong to the family Skia day, which also holds some of their closest relatives. Squirrels and woodchucks. They're basically pygmy squirrels and have adapted to gather resources from places where other animals can't, and they get their name from the chip chip sound that they make, and we'll talk about some more of the sounds that they make later on in the episode.

(02:01): These are pretty small animals as they only weigh one to five ounces. Females are typically larger than the males, but it also depends on their species in areas that are more inhospitable. The size difference between males and females is more noticeable, but in less extreme environments, the difference is less defined. The largest and most commonly known species is the eastern ship mon. If you live on the east coast of the United States, this is probably the species that you're used to seeing. This species is brown and has a white stripe surrounded by two black stripes on their back. They're usually found in forested areas. If you live on the west coast, you might be accustomed to seeing the smallest species of chipmunk called the least chipmunk. On average, chipmunks live for about two to three years in the wild, and they're also diurnal, meaning that they're active during the day.

(02:59): Chipmunks prefer a forage for food where there's enough cover to keep them safe from predators. These little guys have a lot of dangerous predators to worry about, like snakes, hawks, weasels, and owls. Luckily for them, they're extremely quick running at around 20 miles per hour, and while you might think of chipmunks as only eating nuts, they're actually omnivores, meaning that they eat both plants and animals. They're predators to insects, but they also eat their fair share of berries, seeds, nuts and fruits. Chipmunks have also been known to eat fungus and carry on, which is an animal that's already died. Some species will even steal eggs from bird's nests for a tasty snack. But what happens when a chipmunk finds a bunch of food that they're not ready to eat yet? Well, they have an interesting adaptation for this. They're able to store food in specialized cheek pouches and carry the food back to their nests. The pouches can expand to three times the size of their head. Before they stuff food in the pouch, they make sure to bite off any sharp edges that could give them a cut, and they can fit at least 75 sunflower seeds in their cheek pouch at one time, and they're able to store around eight pounds of food in their nests. In preparation for winter, you'll hear more about their nests and how they interact with other individuals. Right after the break

(04:39): This week, I want to give a shout out to Carol from Virginia. Her favorite animal is a frog. Did you know that frog's pelvises can slide along their vertebrae, which helps them jump further? If you want me to give you a shout out, send an email to on wildlife dot podcast@gmail.com telling me your name, where you're from, and your favorite animal.

(05:12): Okay, now back to the episode. Chipmunks are mainly solitary creatures and they only come together really to find a mate. They have a gestation period of around 30 days and they reach maturity at about one year old. They're born in the spring or summer in litters of two to eight individuals in areas with longer summers. There can even be two litters, one in early spring and the other in late summer. These baby chipmunks, which are called kits are born hairless and blind, and they're only about the size of a bumblebee. The mom will only care for her young for two months. The dad doesn't help take care of the kits at all, and right around the eight week mark, the mother will become aggressive towards her offspring and eventually completely deny them access to her burrow. Chipmunks can dig pretty complicated burrows that have tunnel systems.

(06:10): They have areas in the burrow for hoarding food for a nest and even to drain out excess water. The burrows also have multiple entrances and exits so that they can make a quick escape from a predator in order to stay unseen. Chipmunks will remove fresh dirt from the mouth of their burrow to give off the appearance of the burrow being uninhabited. Sometimes different chipmunk species will inhabit the same area, and these species do not get along with each other and they'll compete for resources. A few studies have shown that chipmunk species will outcompete each other based on the habitats that they're adapted for. Species that are adapted for a more terrestrial environment will outcompete species in an area with less trees and species that are more adapted to an arboreal lifestyle will outcompete in areas with more trees. Their social structure and aggressiveness also varies based on the species with terrestrial species being much more aggressive and less social than their ar boreal counterparts.

(07:15): A chipmunk has an average home range of about a half an acre, but will only defend a 50 foot radius around their burrow. They're relatively densely populated with around three to four individuals per acre, but it can get up to around 30 individuals per acre. And there have been a few studies that show that just like people chipmunks all have their own personalities with some being curious, shy, aggressive, or cautious because of these different personalities, there also seems to be a level of trust when it comes to chipmunks signaling danger. Some chipmunks seem to be more reliable in reporting danger than others, and it's been found that other chipmunks realize this and only pay attention to certain individuals. Distinguishing between trustworthy individuals and non-trust individuals is really important because a false signal can lead them to spend a lot of unnecessary energy. And how do they communicate with each other Through vocalization?

(08:18): The chipmunk's main vocalization is the chipping sound, but they do have a variety of different noises that they can make. Different sounds have different meanings. Trills are typically used when evading predators. Chucks are for when an individual detects an aerial predator and chips are given. When an individual detects a terrestrial predator, studies show that they're more sensitive to chucks than ships possibly because aerial predators pose a slightly larger threat and they're not as easy to spot. So needless to say, sound plays a huge role in their lives. Their hearing is much better than their vision. When a chipmunk detects a predator in addition to the noises it makes, it will also assume an alert position, which is a motionless stance. This could be helpful because their brown fur helps them blend in with their forest habitat. Sometimes they can listen to other species calls for information as well.

(09:18): They've been observed using the mobbing calls of a tit mouse, which is a type of bird in order to figure out if they should be ready to run. Mobbing is when birds swarm a potential predator such as an owl or a hawk. Interestingly, in the same study, it was shown that when audio of hawk calls was played, their behavior was unchanged. This is a case of prey responding more acutely to an indirect source of information than a direct source. Chipmunks also demonstrate very different behaviors if they live in an urban environment as compared to a natural environment. Urban chipmunks are found to be less stressed, less mobile, and an overall better body condition than their natural found counterparts. This could be linked to the absence of predators and easy access to food that comes with being in an urban environment. This is one instance where an animal actually thrives rather than declines because of human activity, but they're in the minority.

(10:20): Chipmunks have also been observed to acclimate to traffic patterns extremely quickly, and they'll even move away and towards the road depending on if a car is coming or not. Something that a lot of animals haven't mastered yet. They can also live in areas where winters can be harsh, and if this happens, they'll go through a process similar to hibernation. Most animals store fat by eating a lot of food, but chipmunks will gradually eat a store of nuts that they've collected in the fall throughout the winter. They do go into a sleep like state called torpor, which is more like an intermittent hibernation, but they'll emerge on unusually warm or sunny days in the winter too. In this state, their heart rate and body temperature will decrease by about 75%. This torpor state is risky for the chipmunks because predators can enter the burrow and attack them without even waking them up, but it's also crucial to surviving the cold weather. Torpor length is dependent on the amount of fat in the food that the chipmunk stored with higher fat foods reducing the length. This makes sense as high fat foods are high in energy and females actually go into torpor for a longer time than males. Okay, we're going to take our last break, but when we get back, we'll talk about the chipmunk's importance to the ecosystem.

(11:57): Time for today's trivia question. What does it mean if an animal is crepuscular? Crepuscular animals are mostly active during twilight, not quite day or night.

(12:20): Okay, we're back. Chipmunks are important to ecosystems for a variety of reasons, from being a food source to spreading seeds throughout the forest. They're an important source of food for all kinds of animals like hawks, snakes, foxes, and owls, just to name a few. And all of these animals play an important role in the environment as well, so their survival is key. They also spread the spores of fungus and seeds from plants. The seeds and spores are excreted through the chipmunk's waste or it can get caught in their fur. Sometimes a chipmunk will hide seeds and nuts that they'll forget about, which basically means that they're planting seeds in the ground. Chipmunks are also great for the soil. When they dig their burrows, they're actually aerating the soil, which makes the soil healthier for plants to grow in. As I just talked about, humans and chipmunks can coexist pretty well except for when it comes to gardens and bird feeders.

(13:20): Gardeners and bird watchers often dislike chipmunks because they can be extremely disruptive to their gardens. They like to eat the flowers, berries, and fruit on plants that people commonly have in their garden, and the types of seeds that are normally found in bird feeders are very attractive to chipmunks, and they often pick the feeders clean. This also puts them in close proximity with birds and their nests, and as I said earlier, they'll go after bird eggs. Chipmunks are not only capable of causing damage to gardens, but they can also create significant structural damage to homes. Their burrowing habits can lead them under porches and sometimes even under the foundations of houses. Many people will get frustrated and resort to using lethal methods to get rid of chipmunks, but there are alternatives that are safe for the environment. You can grow plants that chipmunks hate, like daffodils and grape hyacinth.

(14:18): You can also create your own chipmunk repellent by mixing together garlic cloves, chili peppers, water and vegetable oil, and putting them on your plants. What you don't want to do is catch and relocate them. If they're too far away from their burrows, they could starve. Of course, the most effective way to stop chipmunks from coming into our backyards is to have more forest space and less developed areas. This is not the effort of one single person, but it's important to advocate for reforestation, planting more trees and building back our natural forests. Luckily, chipmunks aren't endangered, so the organizations I'd like you to take a look at this week work to protect forests in places where chipmunks live. You should check out the National Forest Foundation Plant with a Purpose and Trees for the Future. Thank you so much for coming on this adventure with me as we explored the world of Chipmunks. You can find the sources that we use for this podcast and links to organizations that we reference at onwildlife.org. You can also email us with any questions at On Wildlife dot podcast@gmail.com, and you can follow us on Instagram at On Wildlife or on TikTok at wildlife. And don't forget to tune in next Wednesday for another awesome episode, and that's On Wildlife.

Jess Avellino (15:50): You've been listening to On Wildlife with Alex Re. On Wildlife provides general educational information on various topics as a public service, which should not be construed as professional financial, real estate, tax, or legal advice. These are our personal opinions only. Please refer to our full disclaimer policy on our website for full details.