Quick answers
| Question | Answer | Scope | Source | Checked |
|---|---|---|---|---|
| Do tree squirrels hibernate? | No. Both park pages say these tree squirrels do not hibernate; the Texas page says stored food gets them through winter. | Eastern gray squirrel, Big Thicket National Preserve (Texas); Douglas's squirrel, Klamath Network parks (northern California and southern Oregon) | NPS, Big Thicket National Preserve; NPS, Klamath Network | |
| Do ground squirrels hibernate? | Yes. Wyoming ground squirrels go underground in late July or early August and stay there until March or April. | Wyoming ground squirrel, Florissant Fossil Beds (Colorado) | NPS, Florissant Fossil Beds National Monument | |
| What they eat | Acorns, nuts, seeds, fruit, corn, insects and mushrooms, and now and then garbage. | Eastern fox squirrel, Missouri National Recreational River | NPS, Missouri National Recreational River | |
| Eastern gray squirrel diet | Mostly plants: nuts, seeds and vegetation. | Eastern gray squirrel; Big Thicket National Preserve (Texas) | NPS, Big Thicket National Preserve | |
| How long they live | 1 to 6 years on average. | Eastern gray squirrel, Lowell (Massachusetts) | NPS, Lowell National Historical Park | |
| Litters per year | One to two litters a year, depending on how much food there is. | Eastern gray squirrel; Big Thicket National Preserve (Texas) | NPS, Big Thicket National Preserve | |
| Pregnancy and litter size | 5 to 6 weeks of pregnancy, then 4 kits on average, born naked and blind. | Douglas's squirrel; Klamath Network parks (northern California and southern Oregon) | NPS, Klamath Network | |
| How big they get | Up to 37 cm (14 inches) long, tail included. | Douglas's squirrel; Klamath Network parks (northern California and southern Oregon) | NPS, Klamath Network | |
| What eats squirrels | Predatory birds, foxes, coyotes, bobcats, mountain lions, raccoons, domestic cats and snakes. | Eastern gray squirrel; Big Thicket National Preserve (Texas) | NPS, Big Thicket National Preserve; NPS, Klamath Network |
In the sources’ own words
Do tree squirrels hibernate?
National Park Service, Big Thicket National Preserve, Eastern Gray Squirrel“Because they are able to store food, they do not need to hibernate to get through the winter when most of their food sources aren't available.”
National Park Service, Klamath Network, Douglas's Squirrel“In the fall, they busily prepare for the coming winter, since they do not hibernate.”
Scope: Eastern gray squirrel, Big Thicket National Preserve (Texas); Douglas's squirrel, Klamath Network parks (northern California and southern Oregon)
Do ground squirrels hibernate?
National Park Service, Florissant Fossil Beds National Monument, Squirrels“The squirrels enter their burrows in late July or early August and hibernate until the following March or April.”
Scope: Wyoming ground squirrel, Florissant Fossil Beds (Colorado)
What they eat
National Park Service, Missouri National Recreational River, Squirrels“…they eat a wide variety of foods like acorns, nuts, seeds, fruits, corn, insects, mushrooms, and occasionally garbage.”
Scope: Eastern fox squirrel, Missouri National Recreational River
Eastern gray squirrel diet
National Park Service, Big Thicket National Preserve, Eastern Gray Squirrel“Squirrels are mostly herbivorous, living off of nuts, seeds, and vegetation.”
Scope: Eastern gray squirrel; Big Thicket National Preserve (Texas)
How long they live
National Park Service, Lowell National Historical Park, Squirrel“Average Lifespan: 1 - 6 years…”
Scope: Eastern gray squirrel, Lowell (Massachusetts)
Litters per year
National Park Service, Big Thicket National Preserve, Eastern Gray Squirrel“Females will have one to two litters per year, depending on how much food is available.”
Scope: Eastern gray squirrel; Big Thicket National Preserve (Texas)
Pregnancy and litter size
National Park Service, Klamath Network, Douglas's Squirrel“An average of 4 naked and blind kits are born after 5–6 weeks of gestation.”
Scope: Douglas's squirrel; Klamath Network parks (northern California and southern Oregon)
How big they get
National Park Service, Klamath Network, Douglas's Squirrel“The Douglas's squirrel can grow to 37 cm long (14 inches), including its tail.”
Scope: Douglas's squirrel; Klamath Network parks (northern California and southern Oregon)
What eats squirrels
National Park Service, Big Thicket National Preserve, Eastern Gray Squirrel“Predatory birds, foxes, coyotes, bobcats, mountain lions, raccoons, domestic cats, and snakes will all eat squirrels.”
National Park Service, Klamath Network, Douglas's Squirrel“Northern goshawks (Accipiter gentilis) and large owls commonly hunt the Douglas's squirrel, though ground predators, such as bobcats, weasels, and martens, also eat them.”
Scope: Eastern gray squirrel; Big Thicket National Preserve (Texas)
What these sources do not say
- Whether all ground squirrels keep the same dates. The July-to-April timing is for Wyoming ground squirrels at one park.
- A lifespan for fox or Douglas's squirrels. The only figure here is for the eastern gray squirrel.