Eastern Chipmunk
Fast Facts
Where: Wide variety of settings ranging from forests, shrublands, meadows, backyards, and parks
Size: 2-5 oz., 3-4.5 inches long, with a 3-4 inch long tail
Diet: Variety of nuts, seeds, fruits, berries, mushrooms, worms, insects, amphibians, bird eggs, and some baby birds
Active in the Northeast from Spring-Fall; are underground in their burrows throughout the winter.
Live most of their life in underground burrows where they rest and sleep, raise their young, store their food, and overwinter in.
Spend a large amount of their active time above-ground searching for food; much of the food that they collect they store away in their burrows as food for the winter.
Live alone except when female is raising her young.
Female typically has two litters each year; each litter most commonly contains 2-6 young (“pups” or “kits”).
Spend winter in a repeated periods of “torpor” where they enter a type of deep sleep for several days at a time during which their heart rate, body functions, and body temperature drops dramatically. Then they “wake up” briefly to eat, dispose of their waste, and then return back to a torpor state.
They don’t hibernate as they are unable to build-up enough fat to last them through an entire winter.
They can live up to ~8 years in the wild, though most live less than 2-3 years.
Creature Feature
Photo by David Morris
Introduction
The Eastern Chipmunk may be one of the most familiar and recognizable animals in the Northeast. They are often found in people's yards. They are also found in forests, shrubby areas, meadows, and parks (including in cities).
Photo by Scott Knecht
They mainly live alone except for when a female is raising her young (which she does by herself). Chipmunks are active in the Northeast from spring to fall. They stay underground in burrows through the winter where they are in a hibernation-like state called “torpor.” (click here for a comparison of torpor and hibernation).
Photo by Lynn Griffiths
Food, Food, and More Food
Chipmunks spend much of the time they are out of their burrow searching for food. Much of their food is nuts, seeds, berries, and fruits. They also eat mushrooms, worms, insects, amphibians, bird eggs, and sometimes baby birds.
Photo by Jeff Tome
Much of the food they gather they will store away in their burrows for food for winter. By the start of winter, a chipmunk may have a gallon-and-a-half of seeds and nuts stored. This is enough to last them through the winter, and can be as many as 5,000 or more seeds and/or nuts.
Photo by Jeff Tome
Chipmunks will also bury food in different places scattered throughout where they live. They do this mainly so that they have a backup food supply if their collection of food in their burrow is stolen by another chipmunk or some other animal.
Photo by Bill Bunn
A Burrow Lifestyle
When not out-and-about searching for food, chipmunks spend most of their life in their underground burrows. They use these burrows as safe places to: rest, spend the winter in, raise their young, store food, and to escape from bad weather in.
Photo by Bill Bunn
They often construct their burrow systems themselves, many times using old root channels through the soil. Some will live in an existing burrow system that is no longer occupied by the original resident chipmunk.
Illustration by Meg Sodano
Eastern Chipmunk burrows often have two or three levels of connected underground tunnels. One level has a wide room with leaves and grass, which is their "nest." It's where they rest and sleep, and where the female raises her young. The other one or two levels have rooms which is where they store their food (their “hoard”). Additionally, they often dig drainage tunnels. These tunnels go straight down from the lowest tunnel to drain water and keep the burrow dry. The entire burrow system is typically less than three feet below the ground.
They usually use one main entrance to enter and exit their burrow. There are also one or more extra entrances, and that are plugged with leaves and debris. They are a backup if the main tunnel collapses or an alternate escape from predators.
Baby “Chippies”
Female chipmunks usually have two litters of young each year. The first is in spring and the second is in late summer. Each litter has 2 - 6 young, which are called “pups” or “kits.” They are born after an ~ 31-day pregnancy. The young are blind, without fur, and are about the size of a bumblebee at birth. The mother will raise them alone. They will nurse from her and stay in the nest for their entire first month.
Photo by Sherwood Lincoln
The young grow quickly. By 1 month old, their eyes are open and their bodies are covered in fur. At ~6 weeks old they begin to take trips out of the burrow learning to find food. They will travel further and further from their burrows over the next ~2 weeks. At ~8-10 weeks old, their mother makes them leave her burrow. She sends them off to each find or make their own burrow system to live in.
Photo by David Morris
A Year in the Life
Eastern Chipmunks start their aboveground activity each year in early spring when it gets warmer. Males often leave their burrows 1-2 weeks before females. Soon, they focus on finding a female(s) to mate with.
Photo by Ronald Zigler
Chipmunks can breed at ~1 year old. The first of the two breeding seasons in a year often starts within a week after the female emerges in early spring. The second breeding season is in mid-to-late summer.
Photo by Bill Bunn
Adults are very active above-ground from early-spring until ~early-July, primarily feeding and collecting food to store in their burrow. They are only active above-ground during the daytime and remain in their burrows at night and during bad weather.
Photo by David Morris
During mid-summer (~July and August), Eastern Chipmunks reduce surface activity. This is due to hot temperatures, less food, and increased botfly parasitism risk during this time period.
Photo by Scott Knecht
They breed twice a year. The second breeding season is in June – July. It overlaps the period of reduced surface activity. Then, there is another peak in surface activity. It is from the end of summer to early/mid-fall. They are focused on gathering food to last through the winter.
By mid-to-late November in New England, most Eastern Chipmunks have gone into their burrows. They have begun their overwintering “torpor”. This is a hibernation-like condition.
During torpor their heart rate drops to < 10 beats per minute (compared to ~ 350 during the active season). Their body temperature drops to ~ 40-45°F (compared to ~ 94°F during the active season). They “wake-up” briefly every few-to-several days to eat and dispose of their waste, and then return back to their torpor. They can't store enough fat to last a whole winter. This is why they can't truly hibernate.
Observations by Month
The plots above show the number of observations of Eastern Chipmunks for each month for each Northeast State through 2023 (from iNaturalist). You’ll note a general trend of relatively few sightings in Winter, an increasing number of sightings throughout the Spring and early-Summer; a drop in sightings in July and August, followed by another increase in sightings in early-Fall until the beginning of Winter.
How You Can Help Them
Keep cats indoors: If you have cats, keep them entirely indoors or in a wildlife-safe outdoor enclosure; domestic cats are major predators of chipmunks (and of a wide variety of other wildlife species)
Create habitat: Provide woodpiles and/or brush piles in your yard; chipmunks readily use these for cover from predators
Plant wildflower gardens/meadows: Convert part of your yard to native wildflower meadows; among many other benefits of doing this, this creates a source of seeds for chipmunks and provides them cover from predators
Wildlife Out Your Window: Learn more about Chipmunks and ways you can help them in this new book
Podcasts: Here is an interesting podcast about Chipmunks from New Hampshire Fish & Game. And here’s another entertaining one from the Vermont Center for Ecostudies.